1986 TMS Annual Meeting Housing Form 115th TMS Annual Meeting March 2-6,1986 HOUSING INFORMATION • Submit ONE request per form; photocopy form if additional sheets are needed. • All housing requests should be sent directly to your hotel choice. • All reservation cancellations/changes must be processed through the hotel. • Housing reservation deadline - FEBRUARY 7, 1986.
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~-----------------------------------------------------_. MAIL THIS FORM DIRECTLY TO YOUR HOTEL CHOICE
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62
JOURNAL OF METALS • November 1985
TMS Social Highlights TMS DINNER & AWARDS PRESENTATION The annual TMS Reception and Dinner, Monday March 3, will be highlighted by the TMS Awards Ceremony, installation of the 1986 President, and live entertainment. The evening will begin with a reception in the ballroom oJ the New Orleans Marriott Hotel. Following dinner, TMS will b"estow the 1986 honors and awards to Society members in recognition of their achievements and contributions to the field of metallurgy. Barbara Ann Shorts and The Gospel Soul Children will provide the featured entertainment for the evening. Barbara Shorts is a versatile performer specializing in night club and cabaret singing. Her rich voice and stage pizazz have been entertaining New Orleans audiences for years. Ms. Shorts theater credits include the starring role in the internationally acclaimed musical "One
Mo' Time". She appeared at the 1984 World's Fair and Exposition, the New Orleans Jazz and Heritage Festival, and was a guest soloist with the New Orleans-Cincinnati Ballet Company.
TMS EXTRACTIVE METALLURGY LUNCHEON Tuesday, March 4 12 noon Marriott Hotel Carondelet Room
Speaker: William G. Deeks Executive Vice President Noranda Sales Corporation Topic: "Where is the Light at the End of the Tunnel
for the Mining and Metallurgical Industry?"
In addition to being featured in numerous nightclubs, Ms. Shorts has made three recordings, and an appearance on the hit television show "Give Me a Break". Don't miss this entertaining show, Barbara Ann Shorts is a gospel and blues singer with an exciting style that is a proven crowd pleaser. The Gospel Soul Children are one of New Orleans hottest gospel choirs. Their rousing performances enter tained audiences all over the country when they toured with the New Orleans Philharmonic Symphony Orchestra. The Gospel Soul Children also appeared at an Aretha Franklin concert in the Superdome, and have been featured at the New Orleans Jazz and Heritage Festival. The Gospel Soul Children promise a lively performance with their harmonious vocals and dynamic show.
TMS INSTITUTE OF METALS LECTURE AND ROBERT F. MEHL MEDALIST Wednesday, March 5 11:45 am Marriott Hotel Bissonet Room
Lecturer: Professor Howard K. Birnbaum Department of Metallurgy University of Illinois Topic: Environmentally Related Fracture;
Hydrogen Chimera or Reality?"
TMS EXTRACTIVE METALLURGY LECTURE
TMSLIGHT METALS LUNCHEON
Tuesday, March 4 1:45 pm Marriott Hotel Bissonet Room
Wednesday, March 5 12 noon Sheraton Hotel Grand Ballroom D
Speaker: Noel Jarrett Technical Director for Chemical Engineering R&D Aluminum Company of America
Speaker: Timothy Jones Associate Vice President The Naisbitt Group
Topic: "U.S. Extractive Metallurgy -
Topic: "Let the 2nd Century Beginthe year ahead in the Aluminum Industry."
the 80's and Beyond" JOURNAL OF METALS • November 1985
63
1986 TMS Annual Meeting Advance Registration Form ADVANCE REGISTRATION Photocopy this form if additional forms are needed. No refunds issued after February 21, 1986. First Name
Mail form with payment, by FEBRUARY 14, 1986 to: Annual Meeting, The Metallurgical Society, 420 Commonwealth Dr., Warrendale, PA 15086 Last Name
Middle Initial
h
Badge to Read Employer Address City State and Country Employer's Phone Hotel
ZIP Code
I
If AIME Memb er Number
T I I
I I
TI
I
I I I I I-----'
REGISTRATION FEES (Check One)
AIME MEMBERS: "TMS ISS SME SPE Student Members
_ _ $120 120 120 120 Free
ASM Members Members, Founder Societies Nonmember Author SEG CIM Nonmember Student Nonmember
_ _ $120 120 120 120 120 180 25
·Retlred TMS members receive a 50% discount on registration fees.
Nonmembers must check one area of interest only.
o Mining o Metallurgy
o o
[ron & Steel Petroleum
PUBLICATIONS ORDER (Please note: Prices noted are publication prices) AIME MEMBER
_
LIGHT METALS 1986 (includes volume celebrating Hall-Heroult Centennial)
_
EARL R. PARKER SYMPOSIUM ON STRUCTURE/PROPERTY RELATIONSHIPS
LIST
AIME STUDENT
See December JOM and Advance Mailer for Ordering Information $57
$86
$28
SYMPOSIA ROUNDTABLE LUNCHEONS 12:15·1:45 pm Marriott Hotel Tuesday, March 4 • Exhibit Hall $1 7 each __ Experimental Methods I-X __ Earl R. Parker Symposium __ Interfaces in Composites __ Undercooled Alloy Phases __ Sensors I & II __ Refractory Metals& Alloys in Nuclear Applications Wednesday, March 5· Acadia __ Hydrometallurgical Reactor Design & Kinetics __ Plasmas in Metallurgical Applications __ Lead, Zinc & Tin __ Copper, Nickel, Cobalt & Precious Metals
64
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1
Canadian Postal Code
I I I I I I I I
F*A*c*T SHORT COURSE (Facility for the Analysis of Chemical Thermodynamics) Sunday, March 2 9:00 am _ _ AIME/ASM Members $145 _ _ Nonmembers $175
SOCIAL FUNCTIONS Sunday, March 2 _ Concentration and Dewatering Circuits Symposium Reception/Dinner 6:00 PM Hilton $25.00 Monday, March 3 _ AIME Annual Meeting Luncheon, Noon Hilton $23.00 _SME Dinner 6:30 PM Hilton $30.00 _TMS Dinner 7:00 PM Marriott $35.00 _SPE Dinner 6:00 PM Sheraton $30.00 Tuesday, March 4 _ Scotch Breakfast, 7:30 AM Hilton $18.00 _ Coal Div. Luncheon, Noon Hilton $20.00 ~ Extractive Metallurgy Luncheon, Noon, Marriott $20.00 _Industrial Minerals Div. Luncheon, Noon, Hilton $20.00 _ Mining and Metallurgical Society of America Luncheon, Noon, Sheraton $20.00 _ AIME Annual Banquet 7:00 PM Sheraton (Individual ticket holders may sit where they wish. Only full tables reserved) __ Individual Tickets $40 __ Tables (1 0) $400 Wednesday, March 5 _ SOCiety of Economic Geologists Breakfast 7:30 AM Hilton $15.00 _ Light Metals Luncheon, Noon, Sheraton $23.00 _ ISS/PTD Luncheon, Noon, Sheraton $20.00 _ Mining & Exploration Div. Luncheon, Noon, Hilton $20.00 _ Mineral Processing Div. Luncheon, Noon, Hilton $20.00 _ Arbiter Symposium Rec./Dinner 6:00 PM, Hilton $25.00 Thursday, March 6 _Internationally Traded Minerals Symposium Luncheon Noon, Hilton $20.00
Advance Registration Total
$_-
PAYMENT: D American Express D MasterCard
DVisa D Check/Money Order
Card Number _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ Expiration Date
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JOURNAL OF METALS· November 1985
115th AIME ANNUAL MEETING TECHNICAL SESSIONS The numbers in bold type on the left of each session title indicate the page on which that session is listed in the Annual Meeting Technical Program. Sessions will be in the Marriott Hotel, the Sheraton Hotel, and the Hilton Hotel.
PAGE
Session Title
Day/Room/Hotel
82 . . . . . . . . . . .. Alloy Phases ................................................................................................................................wed. AM, La Galerie 1 (M) 1 . . . . . . . . . . .. Alternate Alloying for Environmental Resistance I: Design & Microstructural Control. ............................................................................................... Mon. AM, Mardi Gras L-M (M) 22 ............ Alternate Alloying for Environmental Resistance II: Sulfidation & Hot Corrosion ......... Mon. PM, Mardi Gras L-M (M) 41 ............ Alternate Alloying for Environmental Resistance III: Aqueous Corrosion ..................... Tues. AM, Mardi Gras L-M (M) 63 . . . . . . . . . . .. Alternate Alloying for Environmental Resistance IV: Oxidation 1 .................................. Tues. PM, Mardi Gras L-M (M) 83 ............ Alternate Alloying for Environmental Resistance V: Oxidation 2 .................................... Wed. AM, Mardi Gras L-M (M) 2 . . . . . . . . . . .. Alumina & Bauxite I .....................................................................................................Mon. AM, Pontchartrain Blrm A (S) 23 ............ Alumina & Bauxite 11. ..................................................................................................... Mon. PM, Ponchartrain Blrm A (S) 42 ............ Alumina & Bauxite III ..................................................................................................Tues. AM, Pontchartrain Blrm A (S) 64 . . . . . . . . . . .. Alumina & Bauxite IV ..................................................................................................Tues. PM. Pontchartrain Blrm A (S) 84 ........... , Alumina & Bauxite V ....................................................................................................wed. AM, Pontchartrain Blrm A (S) 3 ........... , Carbon Technology I ................................................................................................... Mon. AM, Pontchartrain Blrm C (S) 24 ............ Carbon Technology II .................................................................................................. Mon. PM, Pontchartrain Blrm C (S) 43 ............ Carbon Technology III ................................................................................................Tues. AM, Pontchartrain Blrm C (S) 65 . . . . . . . . . . .. Carbon Technology IV ................................................................................................Tues. PM, Pontchartrain Blrm C (S) 85 . . . . . . . . . . .. Carbon Technology V ................................................................................................. .wed. AM, Pontchartrain Blrm C (S) 3 ............ Cast Shop Technology & Recycling I: Keynote Address, Grain Refining & Alloying .................................................................................... Mon. AM, Pontchartrain Blrm B (S) 24 . . . . . . . . . . .. Cast Shop Technology & Recycling II: Skim Processing ......................................... Mon. PM, Pontchartrain Blrm B (S) 44 ............ Cast Shop Technology & Recycling III: Metal Treatment ....................................... Tues. AM, Pontchartrain Blrm B (S) 65 . . . . . . . . . . .. Cast Shop Technology & Recycling IV: Vertical & Continuous Casting ................ Tues. PM, Pontchartrain Blrm B (S) 86 ............ Cast Shop Technology & Recycling V .......................................................................Wed. AM, Pontchartrain Blrm B (S) 102 ............ Chemically Induced Interface Migration I ..............................................................................wed. PM, Mardi Gras K (M) 120 ............ Chemically Induced Interface Migration II ..........................................................................Thurs. AM, Mardi Gras K (M) 4 . . . . . . . . . . .. Controlled Thermomechanical Processing ........................................................................... Mon. AM, Mardi Gras H (M) 5 ............ Copper, Nickel, Cobalt & Precious Metals I: High Intensity Smelting Process .................... Mon. AM, La Galerie 5 (M) 25 ............ Copper, Nickel, Cobalt & Precious Metals II: High Purity Metals .......................................... Mon. PM, La Galerie 5 (M) 45 ........... , Copper, Nickel, Cobalt & Precious Metals III: Innovations in Precious Metals Processes A ...................................................................................Tues. AM, La Galerie 5 (M) 66 ............ Copper, Nickel, Cobalt & Precious Metals IV: Innovations in Precious Metals Processes B .................................................................................Tues. PM, La Galerie 5 (PM) 86 . . . . . . . . . . .. Copper, Nickel, Cobalt & Precious Metals V: Extractive Metallurgy of Cobalt ............. .-...... Wed. AM, La Galerie 5 (M) 103 ............ Corrosion & Oxidation ..........................................................................................................Wed. PM, Mardi Gras L-M (M) 104 ............ Crack Propagation ....................................................................................................................wed. PM, Mardi Gras E (M) 86 . . . . . . . . . . .. Creep & Creep Fatigue Interactions ...................................................................................... .wed. AM, Mardi Gras C (M) 6 ............ Deformation I. ...............................................................................................................................Mon. AM, Carondelet (M) 46 ............ Deformation II .......................................................................................................................Tues. AM, Mardi Gras A-B (M) 120 ............ Deformation III ........................................................................................................................Thurs. AM, Mardi Gras E (M) 88 . . . . . . . . . . .. Deformation Processing ....................................................................................................................wed. AM, Regent (M) 7 . . . . . . . . . . .. Earl R. Parker Symposium on Structure/Property Relationships: Microstructure & Mechanical Properties I ................................................................. Mon. AM, Mardi Gras D (M) 26 . . . . . . . . . . .. Earl R. Parker Symposium on Structure/Property Relationships: Microstructure & Mechanical Properties II ................................................................ Mon. PM, Mardi Gras D (M) 47. . . . . . . . . . .. Earl R. Parker Symposium on Structure/Property Relationships: Microstructure & Mechanical Properties III .............................................................Tues. AM., Mardi Gras D (M) 67 . . . . . . . . . . .. Earl R. Parker Symposium on Structure/Property Relationships: Phase Transformations & Alloy Design .....................................................................Tues. PM, Mardi Gras D (M) 8 . . . . . . . . . . .. Electrical Properties of Organic Materials I. .......................................................................... Mon. AM, Mardi Gras C (M) 27 ............ Electrical Properties of Organic Materials 11. ......................................................................... Mon. PM, Mardi Gras C (M) 89 . . . . . . . . . . .. Electronic & Magnetic Materials ............................................................................................wed. AM, Mardi Gras H (M) 27 . . . . . . . . . . .. Engineering Design in Metallurgical & Materials Engineering Curricula ...................................... Mon. PM, Regent (M) Environmental Control ......................................................................................................Thurs. AM, Grand Salon 5-8 (H) 90 . . . . . . . . . . .. Environmental Control & Health I ..............................................................................wed. AM, Pontchartrain Blrm B (S) 105 ............ Environmental Control & Health II .............................................................................wed. PM, Pontchartrain Blrm B (S) 122 ............ Environmental Control & Health 111. .........................................................................Thurs. AM, Pontchartrain Blrm B (S) 8 ............ Environmental Effects I ........................................................................................................ Mon. AM, Mardi Gras A-B (M) 28 . . . . . . . . . . .. Environmental Effects II ....................................................................................................... Mon. PM, Mardi Gras A-B (M) 9 . . . . . . . . . . .. Experimental Methods-Jt. Session-On Microgravity Materials Science Research & High Temperature Science I ................................................................................. Mon. AM, Mardi Gras F-G (M) 29 . . . . . . . . . . .. Experimental Methods-Jt. Session-On High Temperature Science & Microgravity Materials Science Research 11. .......................................................... Mon. PM, Mardi Gras F-G (M) 48 ............ Experimental Techniques in High Temperature Science 111. .....•..................•.........•......... Tues. AM, Mardi Gras F-G (M) 48 ............ Experimental Methods for Microgravity Materials Science Research 1I1. •......................... Tues. AM, Mardi Gras C (M) 69 ............ Experimental Techniques in High Temperature Science IV .............................................Tues. PM, Mardi Gras F-G (M) 68 ............ Experimental Methods for Microgravity Materials Science Research IV ........................... Tues. PM, Mardi Gras C (M) 90 ............ Experimental Methods for Microgravity Materials Science Research V ........................ .wed. AM, Mardi Gras F-G (M) 106 ............ Experimental Techniques in High Temperature Science V ............................................. .wed. PM, Mardi Gras F-G (M) 122 ............ Experimental Methods for Microgravity Materials Science Research VI ......................... Thurs. AM, Mardi Gras C (M) 123 ............ Experimental Techniques in High Temperature Science VI ...........................................Thurs. AM, Mardi Gras F-G (M) 49 . . . . . . . . . . .. Extractive & Process Metallurgy ..............................................................................................Tues. AM, La Galerie 2 (M) 107 ............ Fatigue .......................................................................................................................................wed. PM, Mardi Gras C (M) 91 ............ Forming of Coated & Clad Materials I .............................................................................................wed. AM, Iberville (M)
PAGE 108 ............ 70 ............ 109 ............ 124 ............ 30 ............ 92 ............ 110 ............ 10 ............ 31 ............ 51 ............
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17. 37.
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Session Title
Day/Room/Hotel
Forming of Coated & Clad Materials II ........................................................................................... .wed. PM, Iberville (M) Fracture Toughness ...........................................................................................................................Tues. PM, Regent (M) General Pyrometallurgy I ...........................................................................................................wed. PM, La Galerie 1 (M) General Pyrometallurgy II ........................................................................................................Thurs. AM, La Galerie 1 (M) Grain Boundaries ......................................................................................................................Mon. PM, Mardi Gras K (M) High Resolution TEM Studies of Electronic Materials I. ..............................................................Wed. AM, Bacchus (M) High Resolution TEM Studies of Electronic Materials II ............................................................ .wed. PM, Bacchus (M) High Temperature Alloys I: Non·Optimum Microstructures in Superalloys ................................. Mon. AM, Acadia(M) High Temperature Alloys II: Advances in Thermal·Mechanical Processing of Superalloys ....................................................................................................... Mon.PM,Acadia (M) High Temperature Alloys III: Alternative Materials to Conventional Ni·Base Superalloys ...............................................................................................................Tues. AM, Acadia (M) High Temperature Alloys IV: Advances in High Temperature Materials ...................................... Tues. PM, Acadia (M) Hydrometallurgical Reactor Design & Kinetics I ..................................................................... Mon. AM, La Galerie 6 (M) Hydrometallurgical Reactor Design & Kinetics II .................................................................... Mon. PM, La Galerie 6 (M) Hydrometallurgical Reactor Design & Kinetics 111. .................................................................Tues. AM, La Galerie 6 (M) Hydrometallurgical Reactor DeSign & Kinetics IV ..................................................................Tues. PM, La Galerie 6 (M) Hydrometallurgical Reactor Design & Kinetics V ...................................................................Wed. AM, La Galerie 6 (M) Hydrometallurgical Reactor Design & Kinetics VI ................................................................. .wed. PM, La Galerie 6 (M) Hydrometallurgy/Chemical Processing: General Hydrometallurgy ............................................. Mon. AM, Melrose (H) Hydrometallurgy/Chemical Processing: Biotechnology ............................................................... Mon. PM, Melrose (H) Hydrometallurgy/Chemical Processing: Gallium & Germanium .................................................. Wed. AM, Melrose (H) Hydrometallurgy/Chemical Processing: Novel Techniques in Precious Metals Recovery I PM, Melrose (H) Hydrometallurgy/Chemical Processing: Novel Techniques in Precious Metals Recovery II .............. . AM, Melrose (H) Innovations and Productivity Increase in Non·Ferrous Pyrometallurgical Plants I AM, La Galerie 2 (M) Innovations and Productivity Increase in Non·Ferrous Pyrometallurgical Plants II ...................................................................... Mon. PM, La Galerie 2 (M) Interfaces in Composites I: Mechanical Behavior ............................................................ Tues. PM, Mardi Gras A·B (M) Interfaces in Composites II: Characterization ...................................................................Wed. AM, Mardi Gras A·B (M) Interfaces in Composites III: Reactions .............................................................................Wed. PM, Mardi Gras A·B (M) Interfaces in Composites IV: Graphite/Aluminum; Magnesium .................................... Thurs. AM, Mardi Gras A·B (M) Lead, Zinc & Tin I: Applications Technology; Facing the Challenges of the Changing Market Place PM, La Galerie 2 (M) Lead, Zinc & Tin II: Coping with the Times; Cost, Productivity and Technology Improvements .....................................................................................Wed. AM, La Galerie 2 (M) Lead, Zinc & Tin III: Processing Technology ............................................................................Wed. PM, La Galerie 2 (M) Microstructure & Properties I ............................................. ,.................................................... Mon. PM, Mardi Gras H (M) Microstructure & Properties II ..........................................................................................................Tues. AM, Regent (M) Modeling in Process Metallurgy I: Fluid Flow Phenomena .................................................. Mon. PM, Mardi Gras N (M) Modeling in Process Metallurgy II: Electromagnetodynamics of Metals .......................... Tues. AM, Mardi Gras N (M) Modeling in Process Metallurgy III: Heat Transfer & Chemical Reactions ......................... Wed. PM, Mardi Gras N (M) Ordered Phases ................................................................................................................................ Mon. AM, Bacchus (M) Other Light Metals ................................................................................................................wed. PM, Pontchartrain C (S) Phase Diagrams for Electronic Materials-Progress & Opportunities I ............................ Wed. PM, Mardi Gras H (M) Phase Diagrams for Electronic Materials- Progress & Opportunities 1I ......................... Thurs. AM, Mardi Gras H (M) Phase Stability & Transformations ...........................................................................................Wed. PM, La Galerie 5 (M) Phase Transformation-Equilibria-Aluminum Alloys ....................................................... Thurs. AM, La Galerie 6 (M) Phase Transformations-Kinetics .........................................................................................Thurs. AM, La Galerie 3 (M) Phase Transformations in Copper Alloys I: A Review of the Phenomena ......................... Tues. PM, Mardi Gras I·J (M) Phase Transformations in Copper Alloys II: Effect of Phase Transformations ................ Wed. AM, Mardi Gras I·J (M) Phase Transformations in Copper Alloys III: New Developments in Copper·Base Alloys .....................................................................................................Wed. PM, Mardi Gras I·J (M) Physical Chemistry I: Reduction Processes .......................................................................... Mon. AM, Mardi Gras N (M) Physical Chemistry II: Heterogeneous Kinetics of Metallurgical Processes .................... Tues. PM, Mardi Gras N (M) Physical Chemistry III: Applied Thermodynamics of Extractive Processes ...................... Wed. AM, Mardi Gras N (M) Plasmas for Metallurgical Applications I: Plasma Modeling & Plasma·Materials Interactions AM, La Galerie 1 (M) Plasmas for Metallurgical Applications II: Plasma Applications in Extractive Metallurgy A PM, La Galerie 1 (M) Plasmas for Metallurgical Applications III: Plasma Applications in Extractive Metallurgy B AM, La Galerie 1 (M) Plasmas for Metallurgical Applications IV: Plasma Applications in Metals Processing .........................................................................................................Tues. PM, La Galerie 1 (M) Powder Metallurgy ...................................................................................................................Tues. AM, Mardi Gras H (M) Pretransformation Behavior Related to Displacive Transformations in Alloys I AM, Mardi Gras I·J (M) Pretransformation Behavior Related to Displacive Transformations in Alloys II PM, Mardi Gras I·J (M) Pretransformation Behavior Related to Displacive Transformations in Alloys III AM, Mardi Gras I·J (M) Process Mineralogy Applications to Precious Metal Deposits .............................................. Mon. AM, Process Mineralogy Applications to Mineral Deposits: Exploration, Predictive Metallurgy ................................................................................ Mon. PM, Process Mineralogy Applications to Mineral Processing ...................................................... Tues. AM, Process Mineralogy Applications to Liberation ......................................................................Tues. PM,
II
La Galerie 3 (M) La Galerie 3 (M) La Galerie 3 (M) La Galerie 3 (M)
PAGE ~
Day/Room/Hotel
Session Title
. . . . . . . . . . . . Process Mineralogy Applications to Metallurgical Products
and Refractories .............................................................................................................wed. AM, La Galerie 3 (M)
117 ........... . Process Mineralogy Applications of Cathodoluminescence Microscopy ............................ Wed. PM, La Galerie 3 (M)
n ........... . Rapid Solidification Technology for Titanium Alloys I: Production ~ ........... .
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81 ........... .
and Processing .............................................................................................................Tues. PM, Mardi Gras H (M) Rapid Solidification Technology for Titanium Alloys II: Alloy Development, General, High Strength, & Low Density ......................................................................Wed. AM, Mardi Gras D (M) Rapid Solidification Technology for Titanium Alloys III: Alloy Development & High Temperature ..............................................................................Wed. PM, Mardi Gras D (M) Rapid Solidification Technology for Titanium Alloys IV: Alloy Development & High Temperature ............................................................................Thurs. AM, Mardi Gras D (M) Reduction Technology I: Historical Review & New Processes ............................... Mon. AM, Pontchartrain Blrm D (S) Reduction Technology II: Inert Anode Technology .................................................. Mon. PM, Pontchartrain Blrm D (S) Reduction Technology III: Energy Consumption-Process Control & Anode Effects ..............................................................................................Tues. AM, Pontchartrain Blrm D (S) Reduction Technology IV: The Anode Effect ...........................................................Tues. PM, Pontchartrain Blrm D (S) Reduction Technology V: Chemistry Part A ............................................................. .wed. AM, Pontchartrain Blrm D (S) Reduction Technology VI: Chemistry Part B ............................................................ .wed. PM, Pontchartrain Blrm D (S) Reduction Technology VII: Current Efficiency & Fluid Dynamics ........................ Thurs. AM, Pontchartrain Blrm D (S) Refractory Metals & Alloys in Nuclear Applications I: Space Power .......................................... Tues. AM, Iberville (M) Refractory Metals & Alloys in Nuclear Applications II: Fusion Energy ...................................... Tues. PM, Iberville, (M) Sensors: Devices, Materials & Processing I: Smart Sensors ....................................................... Mon. AM, Bissonet (M) Sensors: Devices, Materials & Processing II: Pyroelectric, Optical & Gas Sensors .........................................................................................................Mon. PM, Bissonet (M) Solid & Liquid Mixtures I .................................................................................................................Tues. AM, Bacchus (M) Solid & Liquid Mixtures II ................................................................................................................Tues. PM, Bacchus (M) Solidification ................................................................................................................................Wed. AM, Carondelet (M) Stochastic Approaches to Fracture 1.....................................................................................Tues. PM, Mardi Gras K (M) Stochastic Approaches to Fracture II ....................................................................................Wed. AM, Mardi Gras K (M) Stress Corrosion & Embrittlement ..........................................................................................Wed. AM, Mardi Gras E (M) Surfaces & Diffusion ........................................................................................................................Mon. PM, Bacchus (M) TMI·2 Accident: Cleanup Progress & Value to Industry 1............................................................... Mon. AM, Iberville (M) TMI·2 Accident: Cleanup Progress & Value to Industry 11 .............................................................. Mon. PM, Iberville (M) Techniques for Characterization of Metallic & Ceramic Powders and Surfaces .............. Tues. AM, Mardi Gras K (M) Thermodynamics & Phase Stability ............................................................................................... Mon. AM, Bissonet (M) Undercooled Alloy Phases I: (Hume Rothery Symposium) ................................................... Mon. AM, Mardi Gras E (M) Undercooled Alloy Phases II: (Hume Rothery Symposium) .................................................. Mon. PM, Mardi Gras E (M) Undercooled Alloy Phases 1I1 ..................................................................................................Tues. AM, Mardi Gras E (M) Undercooled Alloy Phases IV ..................................................................................................Tues. PM, Mardi Gras E (M)
LECTURES & LUNCHEONS Sheraton Hotel-Grand Ballroom D Speaker: Timothy Jones Associate Vice President, The Naisbitt Group Topic: "Let the 2nd Century Begin-the year ahead in the Aluminum Industry"
• TMS EXTRACTIVE METALLURGY LUNCHEON Tuesday, March 4, 12 noon Marriott Hotel-Carondelet Room Speaker: William G. Deeks Executive Vice President, Noranda Sales Corporation Topic: "Where is the Light at the End of the Tunnel for the Mining and Metallurgical Industry?"
• TMS INSTITUTE OF METALS LECTURE AND ROBERT F. MEHL MEDALIST Wednesday, March 5, 11 :45am Marriott Hotel-Bissonet Room Speaker: Professor Howard K. Birnbaum Department of Metallurgy University of Illinois Topic: "Environmentally Related Fracture; Hydrogen Chimera or Reality?"
• TMS EXTRACTIVE METALLURGY LECTURE Tuesday, March 4, 1:45pm Marriott Hotel-Bissonet Room Speaker: Noel Jarrett Technical Director for Chemical Engineering R&D, Aluminum Company of America Topic: "U.S. Extractive Metallurgy-the 80's and Beyond"
• ISS/PTD LUNCHEON Wednesday, March 5, 12 noon Sheraton Hotel-Bayside Section A
• M & MSA LUNCHEON • TMS LIGHT METALS LUNCHEON
Tuesday, March 4, 11 :30am Sheraton Hotel-Bayside Section A
Wednesday, March 5, 12 noon III
TMS Annual Meeting
1985 AII·lnstitute Programming Committee
DEEPWATER PLATFORMS AND THEIR POTENTIAL APPLICATIONS: L.B. Curtis, Vice President, Production Engineering Services, Conoco, Inc., P.O. Box 2197, Houston, TX 77001
Alan Lawley, Chairman Drexel University Dept. of Materials Engineering 32nd & Chestnut Streets Philadelphia, PA 19104 Tel: 215/895·2326
Steel jacket offshore production platforms have evolved over several decades to result in a design that is extremely efficient for the shallow water depths associated with the continental shelves. As the search for oil moves beyond the shelf and onto the continental slopes, the traditional platform becomes less economic due to the fatigue problems resul ting from the more severe dynamiC loads associated with the deepwater environment. Compliant structures, which move significantly due to the action of wind, wave and current loads, have been conceived and deyeloped as an economic deepwater alternative to the conventional structure. Several types of compliant structures have been proposed and placed in service, including catenary-moored floating vessels, flexible and articulated columns, a guyed tower, and a tension leg platform. Some potential applications of various compliant structures are discussed and the impact on future materials engineering development needs will be outlined.
William H. Mullins (SME) Freeman United Coal Mining Company P.O. Box 100 West Frankfort, IL 62896 Tel: 618/932·2164 William H. Dresher (TMS) INCRA 708 Third Avenue New York, NY 10017 Tel: 212/697·9355
THE DEVELOPMENT AND USE OF IMPROVED ALLOY STEELS FOR SOUR OIL AND GAS ENVIRONMENTS: George M. Waid. Senior Research Metallurgist, The Timken Company, 1835 Dueber Avenue, S.W., Canton, 44706
James W. Robison, Jr. (ISS) Pfizer, Incorporated MPM Division 96 Turnpike Road P.O. Box 5848 Wallingford, CT 06492 Tel: 203/265·7784
Ohio
With the more demanding needs of the oil and gas industry for the drilling and production of deeper and more aggressive oil and gas wells have come the development of improved alloy steels to meet these needs. This paper summarizes the evolution of alloy steels from our first encounters with sour gas production in the early fifties in Western Canada and France to the modern alloy steels and processing now being used in these hydrogen sulfide containing environments.
Noel D. Rietman (SPE) Diamond Shamrock Corporation 410 17th Street, Suite 600 Denver, CO 80202 Tel: 303/575·0256
HIGH ALLOYS FOR THE OIL AND GAS INDUSTRIES, A.I. Asphahani, Cabot Corporation, 1020 West Park Avenue, Kokomo, IN
46901
The oil and gas industries face limitations on the safe, reliable use of structural materials and handling equipment. As new opportunities are pursued in the arctic, the deep offshore and sour gas wells, engineers are challenged by the need for materials with higher strength, improved toughness, and enhanced resistance to corrosion and wear attack. Combinations of demanding design/structural criteria and hostile/corrosive environments introduce doubts about the performance of conventional materials, preViously used in less aggressive applications. High performance iron-, nickel-, and cobalt-base alloys are described in terms of their mechanical/physical properties and of their resistance to corrosion and wear. Production and fabrication issues are also addressed. Limitations facing conventional materials are contrasted with the versatility and uniqueness of the high performance alloys. Applications in the Oil and Gas industries are Cited, illustrating successful usage of high performance alloys to reduce maintenance/operation cost, to increase safety, and to eliminate environmental concerns.
AIME ALL-INSTITUTE SESSIONS ENERGY I - DEVELOPMENTS IN OIL AND GAS Monday, March 3, 1986 Grand Ballroom E Sheraton Hotel 2:30p.m. Chairmen: Alan Lawley, Drexel University, Philadelphia, PA 19104; Noel D. Rietman, Diamond Shamrock Corporation, Denver, CO 80202 The first session on energy covers several aspects of oil and gas exploration and production, beginning with a review of the problems and future of the petroleum industry. In searching for oil on the continental slopes, deepwater platforms must be in the form of a compliant structure. Potential applications of such structures are discussed and the impact on future materials engineering development needs cited. The materials interface is illustrated by presentations on improved alloy steels for sour oil and gas environments, and on specialty high performance stainless steels and super alloys for the oil and gas industries.
THE PE:rROLEUM INDUSTRY: IT'S ProBLEMS AND ITS FUTURE, Michel T. Halbouty, Cha~rman of the Board and Chief Executive Offlcer, M1.chel T. Halbouty Energy Co., 5100 WesthelIl'ler Road, SUlte 500, Houston, Texas 77056
The United States has potential oil and gas reserves that could prOVide a satlsfactory petroleum energy supply wlthin the comlng decades, but our dangerous rellance on lfTlX)rts and the impact of negatlve corp:xate restructurlng, lll1Wlse mergers, and self-takeovers preclude to a great extent our tapplng that vast potentlal withtn the required tllTe. I believe there is defin.ltely a good future for the U.S. petroleum lndustry, but that future wlll be only as good as the p:?slttve efforts we rra.k.e to strengthen 1t.
IV
TMS Annual Meeting with the growth of GNP? Were future constraints on electricity supply to arise, what effects might there be on the nation's ability to achieve high rates of long-term economic growth?
AIME ALL-INSTITUTE SESSIONS ENERGYII-CURRENTISSUES 'Fuesday, March 4, 1986 Grand Ballroom E 9:00a.m. Sheraton Hotel Chairmen: William H. Dresher, International Copper Research Association, New York, NY 10017; James W. Robison, Jr., Pfizer, Incorporated, Wallingford, CT 06492 In the second of the two sessions on energy, recent energy trends are examined and a perspective developed for the next half century. From this, it may be concluded that the U.S. can be a major exporter of energy technologies and refined energy products, provided we take a leadership role in energy Rand D. The importance of coal in the energy future of the U.S. is also discussed in light of new technologies for the cleaning and combustion of coal, and for conversion of coal to liquid or gaseous fuels and chemical feedstocks. Attendant challenges and opportunities for Mining and Metallurgical Engineers are explored. The session concludes with an in-depth analysis of past patterns of electricity usage and the nation's economic growth, future electric growth and the GNP, and possible effects of constraints on electricity supply on long-term economic growth.
AIME ALL-INSTITUTE SESSIONS GENERIC MINERAL TECHNOLOGY RESEARCH CENTERS Tuesday, March 4, 1896 Grand Ballroom E 2:30p.m. Sheraton Hotel Chairmen: William H. Mullins, Freeman United Coal Mining Company, West Frankfort, IL 62896; Ronald A. Munson, U.S. Bureau of Mines, Washington, DC 20241 In response to the need for the technology to profitably process mineral resources, and to facilitate government-industryuniversity cooperative efforts, the federal government is funding thirty-one Mineral Institutes at mineral-oriented universities and has established five Generic Mineral Technology Centers. These are dedicated to in-depth research in comminution, mineral systems design and ground control, mineral and industrial waste treatment and recovery, pyrometallurgy, and respirable dust. This session will cover the goals and objectives of the Generic Center Program, describe facilities and capabilities, and highlight on-going research activities.
ENERGY - THE NEXT HALF CENTURY: T. D. Anderson, Oak Ridge National L,boratory, Post Office Box X, Oak Ridge, TN 37831.
GENERIC CENTERS OF MINERAL TECHNOLOGY: J.D. Morgan. & R.A. Munson. U.S. Bureau of Mines. Washington. D.C. 20241
Recent energy trends have been toward reduced energy use, low all imports, excess world all and gas production capacity, and declining real energy prices. Accompanying these events has been a substantial slackening of interest in energy R&D and in new energy technologies. The Assumption seems to be that recent t't'ends will continue well into the future; this kind of energy future Is highly unlikely. What Is a reasonable perspective on the future? First, there is the reality of world population and ita growth. With our best efforts at fertility control, world
In 1969. the Commiuee of Mineral Science and Technology of the National Academy of Sciences concluded that the counlry was "not running out of mineral resources but oul of the mineral technology needed for their profitable production and processing in world competition." The Committee recommended greatly increased government! industry/university cooperative efforts in research and education. The Committee's recommendations were legislated in Title III of Public Law 95-87 of 1977 and reaffirmed in separate legislation: the State Mining and Mineral Resources Research Institute Program. Pulbic Law 98-409 of 1984. To facilitate governmenllindustry/university cooperative efforts. the Federal government is funding 31 Mineral InstilUtes at mineral-oriented universities and has established five Generic Mineral Technology Centers dedicated 10 in-depth research across the entire mineral sector of the economy. Program details are highlighted.
population will about double in the next 50 years; most of the growth will be in those nations now classed as less developed. Energy use world-wide will grow much faster than population even
if conservation is emphasized. The role of the United States In this energy future can be substantial, if we choose it to be. By virtue of abundant energy resources and industrial capabilities,
PYROMETALLURGY GENERIC MINERAL TECHNOLOGY CENTER
I!: G. _C.:- Roberts_q~. Department of Metallurgical Engineering.
the ·U.8. has the opportunity to become a major exporter of energy technologies and refined energy products; this opportunity will be realized only if we take a leadership role in energy R&D.
University of Missouri-Rolla. Rolla. MO 65401. USA. The
University of Missouri-Rolla is the lead school, Others are the Colorado School of Mines, Massachusetts Institute of Technology. University of Minnesota, Ohio State ~niversity, Purdue University and the University of Utah, Each school is contributing in its own particular area of expertise and together they constitute a significant coordinated resource capable of serving industry and government. The special facilities they offer will be briefly described. pyrometallurgy continues to advance rapidly as a distinct area of applied technology. Some of these advances will be described. and related to the need for continued graduate education and research. The various current research projects will be listed and discussed in relation to the center's objectives. The main accomplishments of the Center have been in the field of graduate education and research, The Service for Pyrometallurgy Information provides access to a wide range of literature through the University of Missouri Library~
TIlE IMPORTANCE OF COAL IN OUR ENERGY FUTURE: R. A. Bradley, Oak Ridge National Laboratory, P. O. Box X, Oak Ridge, TN 37831
Coal, the United States f most abundant fossil fuel, will play an increasingly important role in meeting the nation fS energy needs. Although decreasing world prices of crude oil have diverted public attention from this important energy resource, new technologies that enable coal to be burned more cleanly or converted to liquid or gaseous fuels and to chemical feedstocks continue to be developed and demonstrated. Recently developed processes for cleaning coal and for producing stable coal-water slurries provide new opportunities for the use of coal in an environmentally acceptable manner. Fluidized-bed combustion and coal gasification combined-cycle systems capture or remove sulfur in situ, thus permitting the use of coal without contributing to acid precipitation. Although the synthetic fuels industry has not developed as rapidly as expected, important advances have been made in coal gasification and in indirect liquefaction. These processes will provide a sound basis for the introduction of synthetic fuels when needed to meet our energy needs. This paper will explore challenges and opportunities for mining and metallurgical engineers as we move toward the twenty-first century.
MINERAL INDUSTRY WASTE TREATMENT AND RECOVERY GENERIC MINERAL
TECHNOLOGY CENTER, Ross W. Smith, Department of Chemical and Metallurgical Engineering, University of Nevada, Reno, NV 89557. The overall thrust of the Center is focused upon technology for waste disposal and the recovery of critical materials from waste products. The program emphasizes physical chemical information needed to evaluate the technical and economic viability of these processes. The Center encourages participation from industry, the government and other mining and mineral research organizations. In addition~ it is the goal of the Center to train graduate mineral industry students. A mineral inrlustr) waste treatment and recovery reference center serves as a repository for books, periodicals and reports. Research projects currently active both at the University of Nevada and the Centers's satellites will be described. The satellites include the University of Idaho, Montana College of Mineral Science and Technology, New Mexico Institute of Mining and Technology, and South Dakota School of Mines and Technology. Integration of the projects occurs at several yearly meetings, at one of which graduate students report on their progress.
ELECI'RICITY USE AND THE NATION'S ECONOMIC GRCMTH. Sam H. Schurr, Deputy Director, Energy Study Center, Electric Power Research Institute, P.O. BoX 10412, Palo Alto, California 94303 Growth in national electricity consumption fell sharply during the past decade. After having registered average rates of 7% or more during the 1950s and 1960s, annual growth during the post-1973 decade averaged only about 2%. Factors behind this drastic change include a slowing down in overall economic growth, changes in canposition, econcm.ic activity away from energyintensive manufacturing towards services and other economic sectors; higher prices for electricity and fuels; and the adoption of conservation practices. The past influence of such factors are evaluated and their future implications assessed. Will electricity consumption grCM much more slowly than in earlier decades? How will future electricity growth compare
of
MINE SYSTEMS DESIGN AND GROUND CONTROL GENERIC MINERAL
TECHNOLOGY CENTER, J. Richard Lucas, Department of Mining and
v
TMS Annual Meeting and morphological properties of the coal dust; the breakage and transport characteristics of coal; the relationship of the dust characteristics with the properties of the coal seam and the type of mining system and equipment used to extract the coal; and the interaction of dust and lungs. The paper will present the research activities of the Center.
Minerals Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061 The Center specializes in mine systems design and ground control, and is involved in many projects for improving the technology, design, health, safety and efficiency of the mining and mineral industries. It consists of six charter participating institutions - the Universities of Alabama, Alaska-Fairbanks, Idaho, Kentucky, Nevada-Reno, and VPI & SUo This Generic Mineral Technology Center, now in its third year, has developed a Research Advisory Counsil, a Project Review Committee and a Library Reference Center to house copies of research publications and to develop a uniqut collection of mining literature, relevant to the research effort and mission of the Center. ApprOXimately twenty research projects are active at the six participating universities.
RESPIRABLE DUST GENERIC MINERAL TECHNOLOGY CENTER:
COMMINUTION GENERIC MINERAL TECHNOLOGY CENTER: University of Utah, Salt Lake City, Utah
J.A. Herbst,
84112
Industry expends approximately 33 billion kwh per annum for size reduction operations. This combined with the fact that the energy efficiency of such operations is typically <5% suggests enormouS potential for improvement and energy savings in comminution. The Center's mission is to improve the level of knowledge and the state of comminution technology through interdisciplinary research and education. It consists of a series of specialized laboratories including, fragmentation, automatic control, size separation, corrosion & wear, computation and characterization. A comminution literature reference center has been established to serve as a national repository for books and periodicals. The Center has made significant advances in understanding the fundamentals of particle breakage, mine site fragmentation and steel wear in tumbling mills; and in measurement and prediction of mineral liberation, advanced control methods for crushing and grinding operations, evaluation and design of size separation devices and improvements in scale-up design procedures for large ball mills. These programs will be discussed.
Robert L.
Frantz and Raja V. Ramani, Department of Mineral Engineering, The Pennsylvania State University, University Park, PA 16802 Studying the vpriations in composition and other characteristics of respirable bust is a specific, high. priority recommendation of the National Academy of Sciences Committee on the Measurement and Control of Respirable Dust in Mines because it has .been demonstrated that factors other than concentration significantly affect the incidence of coal mine workers' pneumoconiosis. In recognition of this need the activities of the Respirable Dust Center are investigating the chemical, physical, mineralogical,
Joint TMS/SME-MPD Program MONDAY,MARCH3,AM GENERAL HYDROMETALLURGY (MPD/TMS) 9:30 AM Chairmen: K. C. Liddell, Washington State University, Pullman, WA J. E. Pahlman, Bureau of Mines, Minneapolis, MN Mixed-Metal Carboxylate Complexes Formed During Solvent Extraction: D. Pouillon and F. M. Doyle-Garner, University of Cafifornia, Berkeley, CA, and E. A. Villegas. Universidade Federal de Minas Gerais, Belo Horizonte·MG, Brazil Solvent extraction with carboxylic acids is pH dependent, with Fe(lIl) being extracted at very low pH, ahead of other metals such as Cu. Ni. Zn. Mn. Cd, Co. and Mg. Extraction and coextraction of these metals has been studied with a Gill carboxylic acid at different temperatures, in sulphate, chloride and nitrate solutions at an ioniC strength of 2M. The experimentally observed separation factore for Fe(llI) and some divalent metals, such as Cu and Ni. are lower than the theoretical values, based on the extraction behavior of single-metal solutions. These low separation factors are attributed to the formation of mixed-metal carboxylate complexes. Infrared, UV/visible and mass spectrometry studies have detected such complexes in mixtures containing Fe(llI) with Ni. Co, and Mn. The composition of these complexes has been estimated from the coextraction data by a statistical computer technique.
The Effect of Ionic Strength and Temperature on Dlffuslvlty of Cobalt and Nickel: K. N. Han and T. K. Kang, South Dakota School of Mines & Technol· ogy, Rapid City, SD The diffusivity of cobalt and nickel ions have been measured using a diaphragm cell technique. The effect of anions including chloride, nitrate, and sulfate on the diffusivity of cobalt and nickel was investigated over the concentration range of O.OOS-O.SM. An empirical relationship between diffusivity of these metal ions a'nd can· centration was found to be: 0 = A· c-n; where 0: diffusivity (cmtls); A: 1.48 x 10-·icm:l/s for chloride, 1.37 x 10-~ for nitrate, and 1.21 x 10-·\for sulfate; C: molar concentration of electrolytes; n: -0.0497 for cobalt and -0.0355 for nickel. The effect of temperature on the diffusivity was also studied. Arrhenius activation energy values of 3500-4300 cal/mol have been identified for cobalt and nickel ions.
sented which permit leaching and precipitation reaction paths to be visualized and systematized. With the aid of these diagrams, the concepts of dissolution, precipitation, and selectivity windows are illustrated and typologies of selective leaching and precipitation processes are identified. Applications of these concepts to selected well-known hydrometallurgical systems as well as to novel separation paths are presented.
Lead Production from Galena Concentrates by Oxidative Leaching and Electrowlnning: A. Y. Lee, A. M. Wetherington, and E. R. Cole Jr., Bureau of Mines, Rolla, MO Researchers at the Bureau of Mines Rolla Research Center have developed an effective oxidative leaching-electrowinning method to recover high-purity lead metal and elemental sulfur from galena concentrates. This low-temperature process eliminates sulfur gases and lead emissions, in contrast to the current high-temperature smelting technology. The method consists of 1) oxidative leaching with HtO t • Pb0 2 • and waste fluosilicic acid at 95°C to produce a solution of PbSiF6 and a residue containing elemental sulfur and other metal values; 2) electrowinning of the PbSiF 6 solution at 35°C to produce 99.99 pct lead metal and HzSiF 6 ; and 3) solvent extraction to recover sulfur, leaving a residue containing copper, silver, and other metal values. Spent electrolyte was recycled repeatedly with impurity buildup controlled by controlling the leach parameters.
Hydrometallurgical Segregation-Flotation Processes for Concentrating Metal Values: B. A. Krebs. Oklahoma City, OK, and W. A. Yuill, Glendale, CA Several processes have been developed to concentrate metal values using a hydrometallurgical step followed by beneficiation. The beneficiation step has been flotation but could also be magnetic, gravity or some other beneficiation step. Anaconda Minerals Co. has developed a process to increase copper concentrate grades from 20-25% to about 60% with no appreciable loss of overall recovery. Another process was developed to obtain good recovery of precious metal values from roast-leach residues. This technique has potential for other applications provided certain criteria are met. These criteria are discussed in detail.
Extraction of Gold and Sliver from a Refractory Arsenlferous Pyrite Concentrate: A. Kontopoulos, M. Stefanakis, and D. Demetriades, Aegean Metallurgical Industries, S.A., Athens, Greece In the present paper, experimental results for the extraction of Au and Ag from the Olympias arseniferous pyrite concentrates are presented. The concentrate has an average analysis: Fe 39·41%. S: 41·42%, As: 10-12%, Zn: 0.6-1.15%, Cu: 0.07·0.10%. Pb: 0.5·0.8%. Sb: 0.08-0.15%, Au: 26·30 ppm. Ag: 30-40 ppm. and is refractory in nature, as evidenced by the low Au and Ag recoveries experienced by direct cyanidation treatment. Therefore, an oxidation pretreatment is necessary before the Au and Ag extraction step. The treatment described in the present paper involves: a) A thermal oxidation step. This is either a single-stage oxidizing roasting, or a two-stage magnetizingoxidizing roasting; b) An acid washing step of the cinders (optional), for the removal of As and other non-ferrous impurities; and c} An Au and Ag extraction step from the cinders. This involves either cyanidation or acidic thiourea leaChing.
Hydrometallurglcal Stability Diagrams: Visual Aids for Process Design and Analysis: K. Osseo-Asare, The Pennsylvania State University, Univer· sity Park, PA The successful design of selective hydrometallurgical separation processes is often dependent on the ability to enhance the dissolution (or precipitation) of a given metal while simultaneously suppressing (or enhancing) the solubility of other metals. In this presentAtion. schematic Eh·pH. 10g(M)·pH. and 10g(ligand)·pH diagrams are pre-
VI
TMS Annual Meeting -
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NOVEL TECHNIQUES IN PRECIOUS METALS RECOVERY I
MONDAY, MARCH 3, PM
(MPD/TMS) 2:00 PM
BIOTECHNOLOGY
Chairman: S. Raghavan, University of Arizona, Tucson, AZ
(MPD/TMS)
Thiosulfate Technology for Precious Metal Recovery: D. Zipperian and S. Raghavan, University of Arizona, Tucson, AZ; and J. Wilson, Kerley Indus-
2:30 PM
tries Inc., Sahuarita, AZ
Chairman: J. B. Hiskey, Arizona Bureau of Geology & Mineral Technology, Tucson, AZ
A detailed analysis of a thiosulfate leaching technique for gold and silver recovery from ores will be presented. The presentation will consist of three parts: 1) physical chemistry of thiosulfate-precious metal-water systems with special reference to solution instability problems, 2) optimization of leach conditions, and 3) feasibility of recovery of silver and gold from leach liquors using cementation and resin-ion exchange methods. The eHect of key experimental variables such as ammonium thiosulfate concentration, copper sulface concentration, and pH on leaching and recovery techniques
The Bloaccumulatlon of Metals by Freshwater Green Algae: J. M. Wood, and F. Eng/e, Gray Freshwater Biological Institute, Navarre, MN Green algae have been found to be much more resistant to heavy metals than bluegreen algae. Several mechanisms for resistance to toxicity have been recognized in laboratory strains of Cyanldlum, Chlorella and Chlamydomonas. Cyanldlum and
will be analyzed. A statistical analysis of the leaching results to identify the most important variables in leaching will also be discussed.
ChIarella both grow at low pH in acid mine water. Cyanldlum removes metal ions from solution by precipitation as metal sulfides whereas Chlorella complexes metal ions to
Gold Dissolution In Chloride Solutions: J. W. Langhans and K. P. V. Lei, Bureau of Mines, Reno, NV
the cell surface (I.e. cell wall) and therefore functions as an efficient ion exchange vehib~th the resistance and bioaccumulation of toxic heavy metals.
cle. We have shown that Ca 2 +, Mg2+, K+, and Na+ are of critical importance in
Recovery of Sliver and Gallium from Flue Dust with Acidified Thiourea Solutions: B. Pesic and J. E. Wey, University of Idaho, Moscow, ID
Bacteria In Ore Deposit Genesis and Minerai Exploration: J. R. Watterson, U.S. Geological Survey, Denver, CO
The research on application of thiourea in precious metals hydrometallurgy was extended on treatment of flue dust from phosphate industry. The flue dust from
Microbial Production of a Metal Binding Protein: J. F. Wo/pram, EG&G Idaho, Inc., Idaho Falls, ID Biologically-Aided Heap Leaching of a Sliver Manganese Ore: B. A.
Monsanto, Soda Springs, ID, was treated with thiourea in sulfuric acid medium. The flue dust contained substantial amount of silver and gallium, 16 ozlt and.4 kg/t, respectively. The extraction of silver and gallium was monitored as a function of: thiourea concentration, sulfuric acid concentration, particle "size, and temperature. The
Krebs, OklahOma City, OK, and D. A. Milligan, Kerr-McGee, Oklahoma City,
pretreatment of dust was also examined. It was found that dissolution of Ag was depen-
OK
dent of thiourea concentration. A complete dissolution of silver was achieved with 1 M thiourea within 1 hour. Gallium recovery was about 60% and independent of all parameters except H2S0~.
A number of bacteria/reagent combinations were screened for their ability to re-
duce manganese from silver/manganese ores and leave the sliver amenable to standard leaching practices. The most cost-effective combination found was
thlobacillus/pyrlte/sulfuric acid. In addition, the use of refractory gold-containing pyrite leaves both the gold and sliver in a recoverable form. The results of shaker tests and laboratory column leaches are shown for varying pyrite additions and acid concentrations, in the presence and absence of bacteria.
Preconcentratlon and Pressure Oxidation of Porgera Refractory Gold Ore: D. R. Weir, Sherritt Gordon Mines Ltd., Fort Saskatchewan, Alba., Canada; J. A. King, Placer Development Ltd., Vancouver, BC, Canada; and P. C. Robinson, Renison Goldfields Consolidated Ltd., Sydney, Australia
GALLIUM AND GERMANIUM
The complex mineralogy of the Porgera resource has a pronounced effect on process selection for the recovery of refractory gold and silver. Intimate association of gold with pyrite necessitates a high degree of sulphur preoxidation In order to achieve acceptable levels of gold recovery. Acid pressure oxidation has been demonstrated to be the only commercially proven process capable of achieving the required level of pyrite oxidation. Gangue mineralization dictates preconcentration of the sulphides to limit
(MPD/TMS) 9:00 AM
the acid consuming capacity and carbon dioxide generation during oxidation. However, the relationship between concentrate sulphur grade and gold recovery to concen·
Chairmen: B. A. Krebs, Oklahoma City, OK D. R. Weir, Sherritt Gordon Mines, Ltd., Ft. Saskatchewan, Alba., Canada
trate ultimately governs the optimum degree of sulphide preconcentration. Mlnlpflotlng of the preconcentration and oxidation stages of the Porgera flowsheet are described. The influence of these processes on subsequent recovery of precious metals together with the technical and economic necessity of concentrate pretreatment prior to oxidation are discussed.
Precious Metals Recovery from Pressure Oxidized Porgera Concentrates: D. R. Weir,Sherritt Gordon Mines Ltd., Fort Saskatchewan, Alba., Canada; P. C. Robinson, Renison Goldfields Consolidated Ltd., Sydney, Australia; andJ. A. King, Placer Development Ltd., Vancouver, BC, Canada Preconcentratlon of Porgera ore results in high recoveries of gold into gravity and
Gallium and Germanium Recovery from a Western Ore: J. J. Esser, Electronic Data Systems Corp., Warren, MI; J. C. Judd and J. H. Maysilles, Bureau of Mines, Salt Lake City, UT The Bureau of Mines Is Investigating methods for recovering gallium and germanium from primary sources such as low grade ores. More than 90% of each element was
flotation concentrates. The bulk of the gold is contained in auriferous pyrite flotation concentrate and is not readily recoverable by direct cyanidation. Oxidation in autoclaves at high pressure and temperature produces a residue which contains the gold in recoverable form. Pilot plant treatment of the autoclave residue is described, through
dissolved from a southwestern Utah are by pressure leaching with sulfur dioxide, and 80% or more of each was altered into a volatile form by roasting at 1030 degrees Co under reducing conditions. Multistage leaching procedures to minimize reagent re-
quirements and roast-Ieacn and offgas treatment techniques that make most effective recovery of altered Ga-Ge compounds are being investigated.
washing and jarOSite decomposition stages, to cyanide leaching and recovery of gold and silver by carbon-in-pulp techniques. The problems associated with disposal of
Electrolytic Recovery of Gallium from Dilute Solutions Employing Mlcroelectrodes: G. E. Stoner and G. L. Cahen, Jr., University of Virginia, Charlottesville, VA, and R. C. Paciei, Naval Air Development Center, Warminster, PA
plant effluents are addressed.
Recovery of Gold from Alkaline Cyanide Solutions by Solvation Extraction and Direct Electrolysis: R. Y. Wan and J. D. Miller, University of Utah, Salt Lake City, UT
The recovery of gallium from dilute solutions is known to be slow and ineffiCient due to competing hydrogen evolution and the limitations of mass transport. In the present work, an approach was taken employing microelectrodes to enhance the rate of mass transport and thus to increase the rate of gallium recovery. The effect of plating
Recent research efforts have shown that selective solvation extraction of a gold
cyanide ion pair complex from alkaline cyanide solution is possible with organic phosphorus oxides. These extr.,ctants can selectively load gold to rather high levels, even in excess of10 g/1. However, traditional stripping techniques are not particularly effective.
time was also determined, and the conditions for the optimum recovery of gallium in
In this regard, gold recovery by direct electrolysis of the organic phase has been found to be an Interesting possibility. In batch electrowinning experiments, sheet gold can be
terms of the overall rate as well as the current efficiency were evaluated. It was shown that, with a typical radius of 3-5/-Lm for the individual fibers, considerable enhancement of the rate of recovery of metals from dilute solutions can be expected.
produced at a current density of2 x 10- 3 amp/cm' and a cell voltage of about 2 volts. The current efficiency Is comparable to that obtained in the electrolysis of carbon eluates, and the sheet gold is of high purity.
The Apex Project: Development of a Primary Gallium and Germanium Producer: G. M. Swinkels, North Vancouver, BC, Canada, and J. E. Litz, Hazen Research, Inc., Golden, CO The Apex property originally mined for copper, contains as well, gallium and germanium in iron oxide minerals. In 1982 Musto Explorations Ltd., began an exploration
program to define reserves. A metallurgy was developed and a production decision was reached in late 1983. This paper describes process development, plant construction, and start-up experience.
Some Advanced Uses for Germanium and Gallium: G. H. Laurie andH. C.
Hirsch, Comenco Electronic Matis., Spokane, WA
VII
TMS Annual Meeting
[
THURSDAY, MARCH6,AM
n
I
ENVIRONMENTAL CONTROL (MPD/TMS)
leach with aqueous S02, followed by a neutralization rinse and then by a cyanide leach
of the silver. Silver extractions of 25 to 82% were obtained with this method compared to less than 10% for direct cyanidation. Manganese extractions of 60 to 95% were also obtained.
Direct Recovery of Gold with a Novel Solvent Extraction-Precipitation System: G. P. Demopoulos and S. Kelebek, McGill University, Montreal, PQ, Canada, and G. Pouskouleli, CAN MET, Ottawa, Canada A novel solvent-extraction based process has been developed for the purification of gold from contaminated chloride feed solutions. The process involves (I) fast « 1 min) selective extraction of gold at very high loading from acidic chloride solutions
containing base metals and low concentrations of PGM and (II) direct recovery of gold in a powder form by contacting the loaded organic with hot water (80°C) at a ratio NO'~
9:00 AM
Chairmen: R. A. Malone, Kennecott, Salt Lake City, UT W. P. Bradford, AMAX Environmental Services, Inc., Golden, CO EPA's Mine Waste Working Group - A More Responsive Approach to Mining Waste Issues: R. E. Wal/ine, U.S. Environmental Protection Agency, Denver, CO An update of the current activities of EPA's Mining Wastes Work Group is given.
This includes mining waste Superfund site activities, Superfund reauthorization, the RCRA Mining Waste Report to Congress, and the Groundwater Strategy. Emphasis is placed on how these various regUlatory programs will impact mining waste disposal practices. Future trends in mining waste regulation are discussed along with the mining industry's role in these regulatory developments.
1/10 for 2 to 4 hours. The organic solvent used is composed of a commercial alkylated a-hydroxyquinoline, isodecanol, and diluent. Gold powders produced by this method
are rather coarse (70% + 200 mesh) with carbon being the only impurity due to some organic contrainment. Data on the extraction and precipitation behavior of gold along with quality properties of the gold product and recycling properties of the organic solvent will be presented.
Simultaneous Recovery of Sliver and Manganese from Ag-Mn Ores by Acidified Thiourea: B. Pesic andJ. E. Wey, University of Idaho, Moscow, 10 A novel method for Etxtraction of silver and manganese from manganiferrous*sllver ores was examined. The lixivlant used was thiourea in sulfuriC acid solution. The examined leaching parameters were: thiourea and sulfuric acid concentration, temperature,
and particle size. The standard experimental conditions were: Thiourea 0.05M, H,SO, 0.1 M, T 25"C and particle size -60+80 mesh. It was found that both metals dissolved simultaneously and completely within 90 minutes. The most important parameters were thiourea and H2 S0 4 concentration. The absence of either thiourea or H2 S0 4 caused no dissolution of either metal. Temperature and particle size were not important parameters.
A Critical Review of the Hazard Ranking System (HRS) as Applied to MinIng Sites: R. H. Ramsey and S. B. Johnson, James M. Montgomery, Salt Lake City, UT, and T. M. Sadler, Sharon Steel Corp., Denver, CO
Carbon Adsorption of Sliver from Acidified Thiourea Solutions: B. Pesic and J. E. Wey, University of Idaho, Moscow, 10
The Hazard Ranking System (HRS), developed under the National Contingency Plan (NCP). is a standard protocol for rating uncontrolled hazardous waste sites throughout the US. The HRS was intended to evaluate the potential for releases of haz-
This is an extension of the work on recovery of silver and manganese from Ag~Mn ores. Carbon adsorption was considered as the best method for recovery of sliver from thiourea leach solutions. For this reason, it was decided to examine the characteristics
ardous waste into ground water, surface water, or air and to assess the immediate health risks posed by direct contact, fire, and explosion. The HRS was developed spe-
cifically to rank toxic, chemical waste sites ratherthan high volume, low toxicity mining wastes. Consequently, the use of the HRS model to rank the risk or danger posed by
of adsorption of Ag on activated carbon. Coconut hard shell activated carbon was used for the study. Ag(TU),CI complex was dissolved into thiourea solution to give 5gpl stock solution. The studied parameters were: loading isotherms at 25°C, 35°C, and 45°C, initial kinetics as a function of thiourea concentration, temperature, pH, N2 • O 2 , NaS0 3 ,
mining sites results in exaggerated scores which may cause these sites to be ranked
unrealistically high on the National Priority List (NPL).
and initial presence of some cations.
Modified Potential Flow Modeling of Density Stratified Atmospheric Flows Around Terrain Obstacles: J. Halitsky, R. B. Lantz, and K. Woodward, INTERA Technologies, Austin, TX
Heap Leaching High Grade Ore: D. Mosch, Mosch Mining and Exploration Co., Idaho Springs, CO, and M. Harris, New Mexico Bureau of Mines & Minerai Resources, Socorro, NM
Recent experiments in both physical fluid models and the full scale atmosphere
have validated the low Froude Number (stable atmosphere) theory. This theory indicates that the air flow divides into a lower layer which passes horizontally around the
Heap leaching high grade are was developed to process ores from small depOSits of high value. These deposits, often with productions of less than to tons per day, don't justify the expense of a concentration facility, but rarely have are grades or production capacities to send are directly to a smelter. The process uses small scale heaps and a modified heap leach procedure. The process was tested in the lab as bucket leaching and an operating heap of 10 tons was constructed. Cost analysis, based on field test
terrain obstacle and an upper layer which passes overthe obstacle. This paper presents results from a modified potential flow (MPF) model, originally introduced in 1971, and compares the calculations with these experiments. Computer-generated streaklines to demonstrate the stratified flow layering were compared with the towing tank and atmo-
spheric lull-scale observations. These comparisons show that the MPF model com-
results, show that cost can be as little as one tenth that of conventional milling,
pares well with low Froude Number theory in predicting the critical streamline height for flow separation.
smelting, and transportation costs for such ores. This paper will describe the modified leaching process and present a detailed cost study based on field results.
Radiochemical Dating of a Perched Aquifer and Interpretations RegardIng Infiltration Rates: J. V. Rouse, J. H. Kleinfelder & Associates, Sacramento, CA In an attempt to decide between differing viewpoints on the amount of recharge to a perched aquifer system underlying an isolated mesa, a series of samples were subjected to radiochemical age dating. Results indicate that water around the mesa was relatively young, but water under the mesa rim was ancient. Results of the study have widespread significance, since they indicate that the percentage of preCipitation which infiltrated was negligible, even during previous periods of higher precipitation. These findings have significance in design of reclamation covers.
Western Acid Rain Documentary -
The Copper Smelters' Viewpoint:
J. H. Boyd, Newmont Mining Co., Washington, DC
NOVEL TECHNIQUES IN PRECIOUS METALS RECOVERY II (MPD/TMS) 9:00 AM
Chairmen: K. C. Liddell, Washington State University, Pullman, WA J. P. Pemsler, Castle Technology Corp., Woburn, MA Refractoriness of Certain Gold Ores to Cyanldatlon: Probable Causes and Possible Solutions: M. C. Jha, AM AX Extractive Research & Development, Inc., Golden, CO In this century, cyanidation has established itself as the main process for extracting gold from ores. However, many ores exhibit refractoriness to the standard cyanldation process. The presence of carbon, tellurium, and sulfides (particularly those of antimony, arsenic, and iron) is generally the main cause of the refractoriness. The problem is usually solved by either changing the cyanidation conditions or providing a pretreatment which normally involves oxidation. This paper presents results from studies that help in understanding the causes of refractoriness of various gold ores. This is followed by a discussion of many processes that have been developed to solve the problem such as intensive cyanldation, pressure cyanidation, carbon-in-Ieach cyanidation, and pretreatment processes such as roasting, chlorination, autoclave oxidation, and bacterial mddation.
Dual Leaching Method for Recovery of Sliver and Manganese from Domestic Manganlferrous Sliver Deposlts:J. E. Pahlman, Bureau of Mines, Minneapolis, MN The Bureau of Mines has conducted research on a dual leaching method for economic recovery of the 2 to 7 oz./ton of silver and 2 to 28% manganese contained in do-
mestic manganiferrous silver deposits that occur throughout the western US. The method is an in situ or heap leaching technique that features an initial manganese
VIII
TMS Annual Meeting 1
MONDAY AM
ALTERNATE ALLOYING FOR ENVIRONMENTAL RESISTANCE I: Design and Microstructural Control Sponsored by the TMS/ASM-MSD Corrosion and Environmental Effects Committee Monday, March 3, 1986 Mardi Gras L-M Marriott Hotel 8:30a.m. Session Chairmen: S. K. Banerji, Ferroalloys Division, Foote Mineral Company, Exton, Pennsylvania 19341 and G. R. Smolik, EGG&G Idaho, Inc., Idaho National Engineering Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415.
(8:30 a.m.) THE DESIGN OF SUSTENITIC ALTERNATE ALLOYS FOR STAINLESS STEELS: M. L. Glenn, Albany Research Center, Bureau of Mines, Albany, Oregon 97321.
factory performance. The microstructural stabil i ty ot terrI tIC stainless steels containing 15 to 18 w/o Cr with ternary additions of 3 to 6 w/o Al has been examined over the range 400 to 550C for times up to 4000 hr. The structural changes were monitored by electrical resistance, microhardness measurements and TEM techniques. Ferritic stainless steels are embrittled bv a phase separation reaction into Fe- rich and Cr- rich ferritics when held at temperatures near SOOC; the reaction is conunonly referred to as 47SC embrittlement. While additions of Al increase the stability of these alloys with respect to 47SC embrittlement, the solidsolution strengthening effect of Al along with greatly increased carbo-nitride precipitation lead to other embrittling effects. The kinetics and microstructural changes are discussed.
(10: 10 a.m.) THE PHYSICAL A.'W MECHANICAL PROPERTIES OF THE NEW HIGH ALUMINUM LOW CHROMIUM CONTENT AUSTENITIC STAINLESS STEEL SUPERALLOYS. J. A. McGurty, R. Nekkanti, E. Rosa and J. Moteff.
The new austenitic sta'inless steel superalloys, which have aluminum contents of 4 to 5% and concomitantly lower chromium contents of 5 to 10% have superalloy properties based on B (Ni AI) or modified B (Ni-AI-Ti) precipitations. Data obtained at the University of Cincinnati are presented which define the tensile and yield strength of these alloys in the annealed and heat treated condition as a function of temperature from room temperature to 2200°F. Also presented are thermal expansion data to 2000°F. Density data show that because of their high aluminum content the densities of these alloys are significantly lower than the densities of conventional iron and nickel base alloys. The property data presented are compared with similar data for austenitic stainless steel alloys and iron superalloys.
(ABSTRACT NOT AVAILABLE) (10:35 a.m.) (8:55 a.m.) PHASE TRANSFORMATIONS AND ALLOY STABILITY IN Fe-Hn-Ni-Cr-AI WELD METAL SYSTEM: J.A. Self, B.F. Carpenter, D.L. Olson, and D.K. Matlock, CoJoraoo School of Mines, Center for Welding Research, Golden, CO 80401.
The qualitative and quantitative effects of manganese, nickel, aluminum and chromium on austenitic weld metal microstructure and phase stability have been characterized and analyzed. It has been found that simple, linear equations for the compositional dependence of the martensite start temperature (M ) are inadequate, due to element interactions in higher alloy syste~s. Such equations are de facto assumptions of ideal solution behavior, which are known to be justified only in dilute solution (e.g. < 5% alloy). By applying concepts of regular solution thermodynamics, a predictive Ms equation has been derived which is applicable to reduced-chromium austenitic steels. A constitution diagram has been constructed which illuminates the austenite/martensite stability at various temperatures. Aluminum passivated stainless steel weld metal has been examined and a "Schaeffler-type" constitution diagram has been constructed to predict room temperature microstructure from weld metal composition.
LOW ACTIVATION FERRITIC ALLOYS FOR NUCLEAR FUSION REACTORS D. S. Gelles, Westinghouse Hanford Company, Richland, WA 99352 The fusion power reactor concept has an inherent advantage over fission reactor designs; the radioactivity of the fuel decays rapidly with time. However, this inherent advantage will be lost unless reactor structural materials can be employed which Elemental additions of Nb, Mo, Ni, N have similar advantages. have half lives which will lead to high levels of radioactivity even after 100 years of storage. Therefore, the Office of Fusion Energy, DOE has funded development of low activation alloys, i.e. alloys with very limited additions of Nb, Mo, Ni and N. This paper des cr i bes the des i gn and test i ng of one ser i es of alloys from one of the classes of materials being studied. The alloys are bainitic or martensitic stainless steels which have vanadium and/or tungsten substituted for molybdenum. Alloy selection criterion, production and testing will be described including microstructural examination and mechanical properties testing following irradiation by fast neutrons in a liquid metal cooled fast breeder reactor. The results demonstrate that martensitic stainless steels in the Fe-9 to 12 Cr range appear most promising for fusion reactor structural materials applications.
(11 :00 a.m.) (9:20 a.m.) SOLIDIFICATION MODES IN FE-ME-AL STAINLESS STEEL' Dr. Daryush K. Aidun, Assistant Professor and Mr. Jay Suh, Ph.D. Student, Mechanical and Industrial Engienering Department, Calrkson University, Potsdam, NY 13676
The solidification modes of Fe-Mn-Al stainless steel have been suggested from four heats of base metal (8M) and .ipot weld structures. In addition to optical microscope analysis, EDAX was performed on the samples of the four heats by moving across the duplex BM and the weld composite region for the phase analysis. The suggested solidification modes are 1. L + of => of + YA for 0 < w/o C < 0.2 2. L + of + YA => of + Y + a F for 0.2 < w/o C < 0.4 A 3. L + of => YA + of for 0.4 < w/o C < 2 Hardness and Varestraint test reveal that mode 2 and mode 3 may cause embrittlement due to dispersion hardening, and hot cracking problem, respectively. Further experiments for the mechanical test of different solidification modes and X-ray analysis for the lattice parameter of different phases might help to establish the suggested solidification modes as well as mechanical properties.
(9 :45
a.m.)
MICROSTRUCTURAL STABILITY OF SULFIDATION-RESISTANT FeCrAI STAINLESS STEELS AROUND 500C, W.S. Spear, Boeing Aerospace Co., P.O. Box 3999, Mis 73-09, Seattle, WA 98124, D.H. Polonis, Dept. Mat. Sci. and Engr., University of Washington, Seattle, WA 98195.
The addition of Al to Fe-Cr stainless steels greatly enhances their high temperature sulfidation and oxidation resistance, thereby allowing reduction in the amount of Cr required for satis-
STRUCTURAL CHARACTERISTICS AND FRACTURE MECHANISM UNDER COLD TENSION OF Fe-33Mn-SA1-1.4Si ALLOYS WITH 0.6 AND 0.8%C; Marcus V.C. Arabe, Rua Nlouel, 196, aelo Horizonte, 30000, MG, Brazil. Evando M.P. Silva, EEUFMG-Dept9 Metalurgia, Rua Esplrito Santo 35, 29 andar, Belo Horizonte, 30000, MG, Brazil Structura 1 stabi 1ity of aus teni Ie was studied based on 1iterature on binary phase dia9rams and ternary isotherms of the Fe-Mn-Al system containing C and Si. Ferrite, ~-Mn and (Fe-Mnl3 A1C x carbides are among the reported adjacent phases of the austenitic field. The austenitic phase existence and decomposition in Fe-33 Mn-8Al-1.4Si alloys with 0.6 and 0.8%C were investigated by optical metallography, scanning eletronic microscopy and X-ray diffractometry. Hardness and stress-strain data were also obtained in order to assess some of the alloys mechanical properties at room temperature. Hot forged samples showed austenitic structure after furnace cooling or quenching in liquid nitrogen from 1000C. High strength and ductility values were observed, besides a slow strain hardening until fracture; this may be related to a fine dispersion of precipitates in the matrix, probably "perovskite" carbides in the cooled austenite.
(11 :25 a.m.) COMPRESSIVE CREEP BEHAVIOR OF ALLOYS BASED ON B2 FeAl,* N. Mantravadi and K. Vedula, Department of Metallurgy and Material; Science, Case Western Reserve University, Cleveland, OH 44106 and R. H. Titran, NASA-Lewis Research Center, Cleveland, OH 44135.
Alloys based on FeAl are being investigated structural materials with low strategic metal
as potential content, for
2 TMS Annual Meeting termediate temperature applications. Small amounts of Nb, Ta, Hf, Mo, Zr and B show a great deal of promise as alloying additions. Compressive creep data for several of these alloys, in the temperature range 1000 K to 1200 K and over a wide range of strain rates, will be presented. Mechanisms of deformation and relationships between microstructure and steady state compressive creep rate will be discussed. supported by NASA-Lewis Research Center, Cleveland,
A AND BAUXITE I Sponsored by TMS Light Metals Committee Pontchartrain Ballroom A Sheraton Hotel Chairman: B. J. Foster, Kaiser Aluminum and Corporation, P.O. Box 337, Gramercy, LA 70052
(S:30 a.m.) OUTLOOK FOR THE BAYER PROCESS: Drs. R. O. Friederich/N. Oeberg, Swiss Aluminium Ltd., Feldeggstrasse 4, P.O. Box 495, ch-B034, Zurich, Switzerland A review of historical data on Bayer alumina plants start-ing wi th the turn of the century wi II be presented. Development of process, equipment, product, etc. will be analyzed and explained. Evolution of European and American plants wi II be compared, and the trend of further development of alumina plants will be discussed.
(9: 10 a.m.)
PLANT LAYOUT & PREASSEMSLY CONCEPTS FOR ALUMINA PLANT CONSTRUCTION: A. R. Kjar (General Manager - Technology) and A. J. Crisp (Senior Process Engineer), Coma1co Limited. 'i'i rolHos Street, Melbourne, Austral ia 3000 At the present time. while alumina capacity excl.'t;'c\s demand and selling price is depressed, construction of new plant cannot be justified. The capital charges of a new Hayer plant can be as high as the manufacturing cost. Efforts need to be directed at reducing capital costs so as to justify new plant when demand for alumina improves. The present state of Bayer technology allows good product quality with efficient use of raw materials and conservation of energy. Improvements in plant layout and construction methods, such as preassembly, have been shown to reduce capital costs. Layout concepts have been developed initially around modern Bayer plant technology, later incorporating the influence of site conditions and emerging methods of construction.
between the mills by conveyor belt. An increase in feed moisture content to 16-18% caused blockages at the hammer mill, and led to the expedient of flushing the hammer mill with spent liquor diverted from the wet grinding system. This caused severe housekeeping and maintenance problems. After trials a roll crusher was installed in parallel wi th the hammer mill. This now satisfies plant requirements without the use of spent liquor. The original hammer mill is maintained only for emergency use.
(10:40 a.m.) OPTIONS IN THE H:l PROCESS FOR THE PRODUCTION OF
ALUMINA FROM
CLAY, D. E. Shanks, D. C. Thompson, R. M. Arington, and .J. A.. Eisele, Reno Research Center, Bureau of Mines, U.S. Department of the Interior, Reno, Nevada 89512 U.S.A. The Bureau of Mines has conducted in-depth studies on the recovery of aluminum chloride hexahydrate and alumina from domestic kaolinitic clay. The original goal of the studies was to provide the technology for alumina production from domestic raw rna ter ia1s. Curren t research is focused on process improvemen ts that will make clay-hydrochloric acid leaching more competitive with the Bayer Process. Options under investigation include direct leaching of raw clay, changes in leaching acid concentra ticn and stoich iometry, decreased leaching duration, improved solid-liquid separations, elimination of solvent extraction for iron removal, and formation of aluminum oxychloride instead of aluminum chloride hexahyorate as an intermediate product. Implementation couln decrease energy, equipment, and reagent costs by eliminating the calcination step, substituting filtration for thickening and washing circuits, decreasing corrosion, and combining iron removal with aluminum chloride crystallization.
(11 :10 a.m.) THE INFLUENCE OF ALUMINA PROPERTIES ON ITS DISSOLUTION IN SMELTING ELECTROLYTE: A.N. Bagshaw, Research and Development Department, Alcoa of Australia Ltd, P.O. Box 161, Western Australia, 6167, B.J. Welch, Oepartment of Chemical and Materials Engineering, University of Auckland. New Zealand. The dis so 1ut i on of wi de range of commerc i a 11 y produced a1uminas in modified cryolite bath was studied on a laboratory scale. Most of the aluminas were products of conventional refineries and smelter dry scrubbing systems; a few were pilot fluid bed calciner, enabling greater produced in flexibility in the calcination process and the final properties. The mode of alumina feeding and size of addition approximated to the poi nt-feeder s ituat ion. A1 pha-a 1umi na content, B.E.T. surface area and median particle size had little impact on dissolution behaviour. The volatiles content, expressed as L.O.!', the morphology of the original hydrate and the mode of calcination had the most influence. The flow properties of an alumina affected its overall dissolution. Discrete intermediate oxide phases were identified in all samples; delta-alumina content impacted most on dissolution.
(9:35 a.m.) BEHAVIOR
OF
RADIOACTIVE ELEMENTS (URANIUM AND THORIUM) IN THE
BAYER PROCESS: C. Sato, S. Kazama, A. Sakamoto, K. Hirayanagi Shaua Aluminum IndubtLi.es K.K., 7-13, Shibakoen I-chome, Minatoku, Tokyo, Japan It is essential that alumina used for manufacturing electronic devices should contain an extremely low level of o( -radiation. The principal source ofl,)( -radiation in alumina is uranium, a minor source being thorium. Uranium in bauxite dissolves into the liquor in the digestion process and is fixed to the solid phase side as the desilication reaction progresses. A part of uranium remaining in the liquor precipitates together with alumina trihydrate in the precipitation process. The uranium content of alumina trihydrate becomes lower as the precipitation velOCity per unit surface area of the seed becomes slower. Organic matters in the Bayer liquor has an extremely significant impacts on the uranium content of alumina trihydrate. Alumina trihydrate free of uranium is obtainable from the liquor that does not contain organic matters.
(10:00 a.m.) BREAK
(10: 15 a.m.) USE OF A ROLL-CRUSHER TO SOLVE BAUXITE HANDLING PROBLEMS AT SARAMENHA: M. A. Palmieri/So Kumar, Alcan Aluminio do Brasi I S.A. Saramenha, Duro Preto, MG, Bras i I The Saramenha alumina plant was designed to process raw bauxite through a hammer mi 11 and a wet rod mi 11 in series, wi th transfer
(11 :40 a.m.) SUPERFINES' RECOVERY FROM TAILINGS:
J.C.G. Soares, Mineracao
Rio do Norte S.A., Porto Trombetas, Oriximina, PA, Brasil The Trombetas bauxite beneficiation comprises crushing and washing, whereby the plus 150 mesh size fractions are recoverf':d. The washing plant recovery is 65% related to run-of-mine and the minus 150 mesh size fraction is rejected. At present, the 150 to 400 mesh size fraction is being recovered which represents an 8% increase in the bauxite recovery rate. 411 cyclones and vertical filters are used in the superfines recovery process. This paper provides information about the beneficiation and the quality of the Trombetas superfines recovered from tailings.
TMS Annual Meeting 3
CARBON TECHNOLOGY I Sponsored by the TMS Light Metals Committee Monday, March 3, 1986 Pontchartrain Ballroom C 8:30 a.m. Sheraton Hotel Session Chairman: lean-Paul Huni, Alcan International Limited, P.O. Box 1250, lonquiere, Quebec, Canada G7S 4K8
(8:30 a.m.) CARBON ELECTRODES IN THE HALL-HEROULT CELL: A CENTURY OF PROGRESS, Davi d Bel i tskus, Al coa Laboratori es, Al coa Center, PA 15069 Charles Martin Hall and Paul L. T. Heroult were fortunate in that the development of suitable carbon anode and cathode materials in commercial quantities preceded their independent discoveries in 1886 of a commercially successful electrolytic method for producing aluminum. However, even though suitable carbon materials were available for the early commercial cells, the tremendous increase in cell size, efficiency, and productivity over the past century has required substantial carbon electrode developments. This paper reviews the state-of-thea rt of carbon elect rode technology a centu ry ago and traces developments in raw material processing and in electrode manufacture.
(9:30 a.m.) A LABORATORY STUDY OF THE ANODE CARBON CONSUMPTION DURING ALUMINuM ELECTROLYSIS: T. MOftOoglu l ), J. Thonstad and H.A. 0ye, Institute of Inorganic Chemistry and Institute of Technical Electroche",i stry, :·lorwegi an I nst itute of Technology, Uni versity of Trondhei "', N-7034 TRONDHE 1M-NTH, Norway 1) Permanent adr.: r4et a 1 lurgical Eng. depart~ent, Middle East Techn. Univ., Ankara,Turkey An improved experimental arrangement has been developed for precise determination of anode carbon consumption (excluding airburn) during electrolysis. Carbon consumption is determined from the weight loss of anode and it is also calculated from the total amount of anode gas (C02 + CO) absorbed in conventional manner. The effect of anode properties such as baked density, porosity, permeability and sodium content on carbon consumption is reported. The contributions of carboxy reactivity and disintegration of the anodes (dusting) are discussed.
( 1 0 : 00 a. m. ) ANODIC PROCESS IN ALUMINIUM ELECTROLYSIS (WETTABILITY STUDIES
ON CARBON ANODE): ~, M. Zhang, Northeast Institute of Technology, Shenyang, China We studied the relationship between the electrode potential and the wetting angle of molten electrolyte on carbon anode, and the relationship between the electrode potential and double layer capacitance. The maximum point on the potential -wetting angle curve is just opposite to the miniurn point on the potential -- double layer capacitance curve, at 1. OSV, which is the potential of zero charge.
However, sometimes an excessive airburn on the top of the anodes can be observed by anodes which have sufficient good carboxyreacti vi ty and gas permeabil ity. The present paper descri bes the interdependencies between the air reactivity, the thern;,l conductivity, and pot operating parameters on the ai rburn of the anodes.
(11 :30 a.m.) IMPROVEMENTS IN VS ANODE PASTE FORMULATION IN AVILES: Jose P. Sancho, Empresa Nacional del Aluminio, Apdo. 76, Aviles, Spain, ~Rhedey, Alcan International Limited, Kingston, Ontario, Canada K7L 4Z4, and S. K. Nadkarni, Alcan International Limited, Jonqui ere, Quebec, Canada G7S 4K8. The improvements relate to a straight line granulometry, coke of high bulk density, and modified pitch specifications. The formulation was developed in the laboratory and subsequently tested in Aviles Works. A significant decrease in paste binder requirement was r.ealized, smoother anode operation was observed, and paste consumption was reduced by 3%. There was also a substantial reduction in tar fume emission from the anode tops. Anode paste with the improved formulation has been in use at the Aviles and Valladolid smelters since March 1984 with the predicted favourable results.
CAST SHOP TECHNOLOGY AND RECYCLING I: Keynote Address, Grain Refining and Alloying Sponsored by the TMS Light Metals Committee Monday, March 3, 1986 Pontchartrain Ballroom B 8:30 a.m. Sheraton Hotel Session Chairman: E. L. Rooy, Aluminum Company of America, 1501 Alcoa Building, Pittsburgh, PA 15219
(8:30 a.m.) CAST SHOP TECHNOLOGY AND RECLAMATI ON: 100 YEARS OF PROGRESS: Warren S. Peterson, Consultant, 2113 E.37th Ave., Spokane, WA 99203. A revIew of equipment and proctices for melting & casting aluminum process ingots (as opposed to Foundry), plus observations on the recent explosive growth of aluminum recycling. Major changes since the days of Hall and Heroult are described, and the driving forces for these changes discussed. As a 100 year overview, the treatment of individual subjects is necessarily limited in depth, and in some cases to photographs of facilities or equipment. Also, references to work of a number of important contributors could not be included. Significant technical developments are identified including DC (direct chill) casting, in-line degassing and filtration of molten metal, continuous casting systems, EMC (electromagnetic casting), and avilability of new materials of construction, testing devices, and control techniques for melting and casting operations. The need to observe safe practices in melting and casting molten aluminum and its alloys is discussed briefly. New alloys and new casting systems present new problems.
(10:30 a.m.) CARBON RAW MATERIAL EFFECTS ON ALUMINUM REDUCTION CELL ANODES: P. J. Rhedey, Alcan International Limited, Kingston, Ontario, Canada K7L 4Z4, and S. K. Nadkarni, Alcan International Limited, Jonquiere, Quebec, Canada G7S 4K8. In recent years significant variations have been experienced in carbon anode raw material properties, namely impurities and texture of petroleum coke, and in solvent insoluble contents of coal tar pitch. Impurities increase anode consumption mainly due to increased rates of carbon/gas-phase reactions. High porosity cokes impair the mechanical properties of the anodes; neverthe 1ess they can be ut il i zed either by pregri ndi ng or by a lteri ng the aggregate granul omet ry. Pitches wi th low levels of primary QI can be used with satisfactory results. High levels of primary QI in pitch are normally associated with increased impurity content, thus such a pitch may be objectionable for that reason. The beneficial effect of high pitch softening point was confirmed in benchscale test electrodes with a pitch of 135°C (Mettler) softening point.
(9:30 a.m.) THE EFFECT OF TITANIUM AND BOroN aJNCENTRATIONS ON PERFDRMANCE OF AllJMINUM GRAIN REFINERS: Dr. G.T. ~bell, W. Blvd., Newfield, NJ 08344, S.A. Sutker, W. Blvd., Newfield, NJ 08344. '!he Grain Refining properties of a number of Titanium-BoronAltnninurn alloys were evaluated on three carrrercial altnninurn alloys. The results of this study show that Grain Refining efficiency is significantly affected by the concentractions of Titanium and Boron in the Master Alloy. For the range of Master Alloys studied, it was found that la..Br additions of Titanium and Boron were required to obtain a given degree of Grain Refinerrent with the la..Br concentration Master Alloys. '!he greater efficiency of TiB2 in the 1a..Br concentration Master Alloys suggest that a greater percentage of TiB2 particles are active.
(10:05 a.m.) J. L. Kirby, S. A. Levy, R. W. M:::Carthy, Reynolds ).Etals Carpany, ).Etallurgy Laboratory, P. O. Box 27003, Ricinrond, VA 23261.
GRAIN SIZE 'lEST ME'lHOD
(11 : 00 a. m. ) ,ACTORS INFLUENCING THE CARBOXY - AND AIR - REACTIVITY BEHAVIOUR OF PREBnED ANODES IN HALL - HEROULT CELLS: ILK. Fischer, R. Perruchoud, Swiss Aluminiu", Ltd., R&D Carbon, CH - 3965 Chi ppi s, SWITZERLAND. In a previous paper the relation between carboxy - reactivity, gas permeabi 1 ity and anode pel·fomance was described.
Ccmrercial grain refiner vendors enploy in-house grain size testing to quantify perfonnance of their Al-Ti and Al-Ti-B products. Because ITOst vendors test grain refiners in pure aluminum, a void exists between this testing and the grain refine
4 TMS Annual Meeting curves corrparll1g the KBI ring test, ALCAN test, and the cpH tee test. 'Ib insure that not be biased, the irrpact of rre1 t temperature n and perforITEIlce of a rod grain refiner
FDeezing rates for the grain size samples deternuned, and compared to corrrrercial sheet ingots. the sample to ingot grain size was W1dertaken.
ADVANTAGES OF HIGH QUAL lTY S ILGRAI N IN ALUMI NUM ALLOYS: T. J. Kosto, G. H. Boe and E. Kjerpeseth SILGRAIN is the trade mark of ELKEM chemically produced silicon metal. Typical analysis of this material is 98.5-99.0 % Si, and the material comes in a "sandy" form after processing. HIGH QUALITY SILGRAIN,
(H.Q. SILGRAIN,tm),
is a
standard controlled rolling techniques. Recrystallization controlled rolling, in which grain refinement is accomplished by recrystallization at temperatures just above the recrystallization stop temperature, offers an alternative. The addition of Ti inhibits grain coarsening so that the transformation to ferrite takes place in relatively fine grained austenite. Thus, fine ferrite grain sizes can be produced even though relatively low reductions are applied at finishing temperatures above those of normal controlled rolling. The manufacture of seamless tubing is well suited for these techniques since much of the deformation, about 70% of the total equivalent strain, is applied in the first two piercing operations which are performed at about 1100°C. In this investigation, the operation of the seamless tube mill of The Algoma Steel Corp. was simulated using a high temperature torsion apparatus. The Ti bearing, heavy plate steels studied by Ruddle, Baragar and Crawley were employed. Prior to the simulations, the recrystallization behaviour of the austenite was characterized by means of interrupted compression testing.
further chemical
refinement of the original SILGRAIN material. The analysis of this material is typically in the 99.8 - 99.9 % silicon range. H.Q. $ILGRAIN can, as one use, be applied in silicon-aluminum foundry alloys. Such alloys, with low iron/calcium, are especially used for demanding areas in the automobile- and aerospace industry. ELK EM method of alloying H.Q.SILGRAIN with aluminum is by injection into the alloying furnace. Besides having a refiningeffect on the finished product, the silicon metal yield is 99-100 %, and the procedure is labor- as well as time-saving. The method is well established in Europe, and is currently being introduced into the U.S.A. Results from actual industrial practice in Europe and U.S.A. are given.
(11:25 a.m.) REFINING AND ALLOY OF ALUMINUM BY INJECTION: T. Pedersen, E. Myrbostad, ASV Metallurgical R&D Center, N-6601 Sunndalsoera, Norway. Metallurgical basis for injection of salt fluxes for refining and metal powder for alloying are discussed. Results on hydrogen/sodium removal, removal of incl usions and recovery of metal from the dross are given from trials with salt injection in industrial scale. Both commercial fluxes and a salt flux produced by an ASV receipt are used on several alloys in three different casthouses. Based upon theory and practical trials, it seems possible to get all the wanted effects in one salt flux. Results from industrial trials and ordinary production with injection of silgrain, manganese powder, magnesium granules and zinc powder are given with respect to the injection equi pment, running condition and yields. The injection systems have evolved from manual to programmable controllers to computer control. The automatic feeder together with a total handl ing system of the powder will form the basis of alloying in a new casthouse at Sunndal Verk.
(9: 10 a.m.) EVOLUTION OF TRANSFORMATION PRODUCTS FROM THERMOMECHANICALLY TREATED AUSTENITE: T. E. Geiman and L. J. Cuddy, Dept. of
Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802. The type and distribution of austenite decomposition products can be modified by changing any or all of three parameters: steel composition; the state of the austenite (grain size, degree of deformation); and cooling rate. Combinations of these three variables have produced transformation products that appear to differ from those produced by classical isothermal transformation of recrystallized austenite. The present work describes some transitions in transformation products that result from varying the degree of deformation of the austenite.
(9:30 a.m.) THE PROPERTIES OF QUENCHED AND TEMPERED STEEL SHAPES WITH HIGH
STRENGTH AND GOOD TOUGHNESS: Kozo Fukuda, Nobuo Fukushige, Fukuyama Labs., Fukuyama-city, Hiroshima-pref., Keiji Okamoto, Misao Makinohara, Fukuyama Works, Masahiro Ueda, Tokyo Head Office, NIPPON KOKAN K. K., Japan Quenching and tempering process, which can heat-treat homogeneously several kinds of large steel shapes, e.q. L 2s0mm x 2s0mm x 3smm, was developed by reconstructing the conventional type continuous heat treating furnace specialized for anneal ing of steel shapes. Main considerations for reconstructing are, securing cooling starting temperature in quench by curtain burner, and unifying cooling rate at various positions by mist. Using this furnace, T.S. 60kgf/mm 2 (ASTM A537-CI.2-Modify) and 80kgf/mm' (ASTM 514-B) grade steel shapes, and Q-T type 9% Ni (ASTM A553) steel shapes were tested and the
well satisfied results obtained, meeting the requirements of ASTM and having high homogeneity.
CONTROLLED THERMOMECHANICAL PROCESSING TMS-AIME General Abstract Session Monday, March 3,1986 Mardi Gras H 8:30 a.m. Marriott Hotel Session Chairman: L. J. Cuddy, Department of Materials Science & Engrg., The Pennsylvania State University, University Park, PA 16802
(8:30 a.m.) CONTROL ROLLINr, OF MICROALLOYED COPPER STEELS:
J. C. Reed, Jr.
and L. J. Cuddy. Dept. of Materials Science and Engineering. The Pennsylvania State University, University Park. PA 16802. To modify the strength and toughness of copper-bearing steels. the size and distribution of the copper precipitates must be controlled. This can be achieved by combinations of control rolling and accelerated cooling that modify the austenite decomposition products. The present study describes the determination of the proper reheating temperatures, the recrystallization-stop temperatures, and the ferrite-start temperatures of the austenites of two copper-bearing steels. These parameters are needed to design effective control rolling schedules.
(8: 50 a.m.) RECRYSTALLIZATION CONTROLLED ROLLING TECHNIQUES FOR THE PRODUCS. Yue*, P.J. Hunt t and J.J. TION OF LINE PIPE SEAMLESS TUBING:
Jonas*, *McGill University, Montreal, Canada, tThe Algoma Steel Corporation, Ltd., Sault Ste. Marie, Canada. In the production of heavy plate, the limited reductions applied in the finishing range of temperatures prevent the application of
(9:50 a.m.) IMPROVED TECHNIQUE OF THE SOUND HEAVY GAUGE PLATE BY ROLLING
PROCESS: Sadakazu Masuda, Takeshi Hirasawa, Seishi Tsuyama, Hisatoshi Tagawa, Fukuyama Research Laboratories, Technical Research Center, Nippon Kokan K. K., Fukuyama, Japan The authors invest igated the trethod to get the sound heavy gauge plates only by rolling process, and developed the Low-sp.:!ed Heavy Reduction Rolling process, the purpose of which was to secure the necessary temperature, time and compressive stress for e 1 iminat ing micro porosi ties. Futhermore, taking not ice that most micro porosities are distributed in about 50-60% of the mid-width region of ingots, they have developed the Center-portion Heavy Reduction Rolling process which reduces only the area with a high density of micro porosities, partially by the low speed and heavy reduction rolling. In such a partial rolling, the compressive stress in midthickness increases notably as a result of the binding force caused by the un-rolled edge parts and an increase in the reduction amount per pass. It would be possible to manufacture sound heavy gauge plates stably from the conventional ingots by the application of this developed rolling process.
(10: 10 a.m.) INFLUENCE OF PROCESS VARIAHLES ON THE STRUCTURE-PROPERTY RELATIONSHIP OF AISl 1015 AND MICROALLOYED DUAL PHASE STEELS: P • Deb •
Materials Science Group, Naval Postgraduate School, Montere-y-,California 93943, USA, and M. C. Chatarvedi, The University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada The influence of process variables on the microstructure and mechanical properties of AISI 1015 and microalloyed HSLA steels has been studied. Both the steels were deformed 33% (i.e., 8 roll passes) and 66% (Le., 12 roll passes) at 1023 and 1073 K
respectively, followed by quenching in iced-brine solution. It was found that by the proposed thermomechanical processing (IMP) it was possible to improve the mechanical properties of both the
TMS Annual Meeting 5 steels (dual phase) as compared to the as-received (ferrite-pearlite) mechanical properties. These specimens (dual phase) were further tempered at 723, 823, and 923 K respectively tor 1 hour. It is also seen that further tempering at 823 K exhibited better mechanical properties as compared to the specimens intercritically annealed and deformed followed by quenching in iced-brine solution. An attempt has been made to characterize the microstructure and the corresponding mechanical properties of these thermomechanically treated specimens.
( 10:30 a.m.)
COPPER, NICKEL, COBALT & PRECIOUS METALS I: HIGH INTENSITY SMELTING PROCESSES Sponsored by the TMS Copper, Nickel, Cobalt and Precious Metals Committee Monday, March 3, 1986 La Galerie 5 8:30 a.m. Marriott Hotel
Session Chairman: V. Kudryk, ASARCO Incorporated, 901 Oak Tree Road, South Plainfield, NJ 07080
MECHANICAL PROPERTIES OF NEAR BETA TYPE TITANIUM ALLOY Ti-9V-3Mo
-3Al: Y. Mae, T. Oka and A. Hirano, Central Research Institute, Mitsubishi Metal Corp., Ohmiya, Japan 330 In Ti-9V-3Mo-3A1 alloy beta transus is under 800°C, the phase ratio between alpha and beta phase is 1: 1 at 700°C. Thus this alloy can be hot rolled at as low as 700°C and cold rolled over 70% reduction without intermediate annealing. When this alloy is cooled in air or water from 750°C, it shows such low proof stress as 30kgf/nun 2 , which is considered to be caused by transformation induced plasticity. It is advantageous for cold working. After direct aging between 300 and 400°C for severalhours maximum Vickers hardness over 400kgf /mm 2 is obtained. After dir~ct aging at 520"C for 4 hours proof stress over 110kgf/mm 2 is still gained. These results show that this alloy is a high strength heat treatable alloy with good formability.
(10:50 a.m.)
(8:30 a.m.) KINETICS OF SULFIDE EVAPORATION IN HIGH TEMPERAWRE SMELTIN:; PRCCESSES, 1. Barin, M. l.errF!rle, M. M:x:ligell, KHD Humboldt \'iedag kJ, Res. & Dev. ,5000 Cologne 91, Frg.West Germany; A. Knapp, H. Wilhelmi, Technische Hochschule Aachen, Institut Fuer Industrieofenbau und Waenretechnik Irn Huettenwesen, 5100 Aachen,Frg. West Germany. The kinetics of dissociative evaporation of metal sulfides followed by oxidation reactions in the gas phase play an important role in metallurgical high temperature ,;melting processes such as cyclone or flash smelting. For a better understanding of
these phenomena, investigations have been carried out on a small laboratory scale using znS as an example. Sintered znS ccmpacts ""re exposed to plasma heated argon and Ar-02 mixtures with temJO€ratures be~ 1800 and 2200 K. These results canbined with
theoretical calculations are used for the description of the rate phenomena in the cyclone smelting process.
DEVELOPMENT OF IMPROVED PM 2124 AL ALLOY PLATE AND SHEET
MATERIALS·: D. J. Chellman. Lockheed-California Co .• Burbank,CA 91520 The present investigation addresses the fabrication and evaluation of-PM 2124 Al alloy flat rolled materials in accordance with NASA program g'oals for damage tolerance and fatigue resistance. Previous research has demonstrated the outstanding strength - toughness combinations available with PM 2124 Al - Zr mOdified alloy compositions in extruded product forms. The PM composition based on AI-3.70Cu-1.85Mg-0.20Mn with 0.60 wt. pet. Zr was selected for this study. Flat rolled materials consisting of 0.250 in. thick plate and 0.070 in. thick sheet were fabricated using suitable thermal mechanical treatments (TMT). The schedule of TMT variables were designed to yield the extreme conditions of grain structure normally encountered in the fabrication of flat rolled products, specifically recrystallized and uncrystallized. Isothermal aging responses as a function of temperature and time were conducted to identify candidate heat treatment tempers. The PM Al alloy plate and sheet materials exhibited improved strength properties at thin gages compared to 1M Al alloys, as a consequence of their enhanced ability to inhibit recrystallization and grain growth. In addition, the PM 2124 Al alloys offer much better combinations of strength and toughness over equivalent 1M AI. The alloy microstructures were examined by optical metallog-raphy and crystallographic texture methods in order to establish the metallurgical basis for these significant property improvements. .Research sponsored by NASA-LaRe prcgram on High Temperature Al alloys.
(9:00 a.m.) A MATHEMATICAL MJDEL OF TIJE PARTICULATE FlASH OXIDATICN SYSTEM. Y.H. Kim, D:x::torate Fellav,Heruy Krumb Schcol of Mines, COIUiiiIJ1a University, NY,NY 10027; N.J. Themelis,Professor of Mineral Engineering and Chainnan,Henry Krumb School of Mines, Columbia University, NY ,NY 10027. The chalcopyrite oxidation system as practiced in the OUtokumpu flash srrelting process, was mcx:lelled in the direction of stream flav. The merlel was developed on the basis of reaction kinetics and the equations of conservation of mass, m:rrentum and thermal energy; it consists of eight differential equations which are integrated by computer to yield information on the phenomena occurring in particulate flash oxidation systems.
(9: 30 a.m.) IGNITICN TESTING Of' MATERIAlS FRa1
TIJE
KALGCORLIE NICKEL FI1\SH
SMELTER, F .ReA. Jorgensen, CSlRO, Division of Mineral Chemistry, Port Melbourne, Victoria 3207, Australia. (11: 10 a.m.)
METALLURGICAL CHARACTERIZATION OF WARM WORKED AS EXTRUDED AND SOLUTION TREATED WATER QUENCHED DU-3/4% TI: C. V. Zabielski,
U. S. J~nny Nat.eria.ls & ~jechanics Res-ear.::.11 Centei~, i'~etals Rt~-earch Division, Watertown, MA 02172
Metallurgical characterization studies were conducted of U-3/4% Ti in the following conditions; as extruded, extruded and warm worked, and solution treated, water quenched and warm worked. These include metallographic examination, fracture toughness (KQ), and mechanical properties.
(11 :30 a.m.) THEORETICAL PREDICTION OF THE FORMING LIMIT OF ALUMINUM ALLOY SHEET USING COOF MEASUREMENTS: F. Barlat, M. A. Przystupa, D. J. Lege and R. E. Sanders, Alcoa Laboratories, Alcoa Center, PA 15069 The importance of the yield surface shape on the stretchabil ity of sheet material will be discussed and a new model based on the M-K assumption on the existence of an imperfection will be proposed. This new model allows for the use of any constitutive model with isotropic work-hardening and requires knowledge of yield loci as an input. In particular it is possible to use this model with the yield loci obtained from crystallite orientati on di s tri buti on funct i on (COOF) for textured sheets and Taylor analysis. The results of an application of this polycrystalline model to various aluminum sheet alloys will be presented and rel ati onshi ps between crystall ographi c texture, yield surface shape and forming limit curves for these alloys will also be discussed . .
Three nickel concentrates were burnt at the rate of 450 g/min in
a suspension-type burner. Oxygen concentrations of the atmosphere ranged fran 21-35% 02. The ignition terrperature in air varied fran 520-580 C and depended upon the mineralogical composition. Increasing oxygen concentrations in the atmosphere decreased the ignition terrperature while addition of inert materials such as flash furnace flux and boiler dust caused an
increase.
(10:00 a.m.) CXJTOKUMPU FlASH SMELTING--AN UPDATE AND REI'ROFIT CONSIDERATIONS, D.W. Rodolff,Manager,Nonfe=ous Metallurgy, llitoklnnpu Eng.lnc., P.O. Box l6573,Denver, Colorado 80216; M.V. Haani,Manager, Engineering Group; K.A. Helne,Project Manager,Smelter Projects; B.T. Anderson, Consulting Metallurgist,OUtokU!1pl Engineering Division,P.O.B. 27,0220l,Espoo 20, Finland. Continued research and develO!:ments coupled with the experience gained fran the increasing number of operating OUtokumpu flash smelters have resulted in IIDre efficient and reliable operations. Both oJO€rating and capital costs have been reduced and are significantly lower than some independent studies have indicated.
(10:30 a.m.) IMProvEMENTS IN HIGH INTENSITY OPERATION OF TIJE MITSUBISHI PRCCESS AT NAOSHIMA SMELTER, M. Goto, Metallurgy Depart:Irent, Mitsubishi Metal Cbrp. ,No. 5-2,Ohte-Machi, I-chore, Chiycx:la-Ku, Tokyo 100,Japan; S. Kawakita, N.Kikumoto & O. Iida, Naosh:iroa Smelter,Mitsubishi Metal Corp.,Naoshima-cho,Kagawa-Gun, Kagawa-Pref. ,Japan. The Mitsubishi process at the Naoshima Smelter of Mitsubishi Metal Corp. has gradually expanded the production cap3.city since its start-up in 1974. The feed rate of copper concentrates IIDre than 50 mt/hr was operationally tested successfully in June 1985. This p3.per will deal with the high prcx:luctivi ty of the Mitsubishi process in various aspects including kinetic con-
siderations for smelting and converting copper concentrates.
6 TMS Annual Meeting (11 :00 a.m.) EXPANSION OF THE KIDD CREEK CCPPER SMELTER, C. J. NewPan, A. G. Storey and K. Molnar, Copper S!relter and Reflilery, Kldd Creek
~
Mines, Timnins, Q1t. ,Canada.
C")
This paper will cover the results of the current expansion of the Kidd Creek Copper S!relter from the original design of 59,000 tonnes of copper a year to 90,000 tonnes. The Kidd Creek smelter uses the Mitsubishi continuous smelting process.
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II
TION I TMS-AIME General Abstract Session
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Carondelet Marriott Hotel
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Chairman: K. Ted Hartwig, Applied SuperconductiviCenter, University of Wisconsin-Madison, 1500 Johnson t . , Madison, WI 53706
(8:30 a.m.) TWINNING MECHANISM IN METASHBLE ELEVATED TEMPERATURE DEFORMATION,
Anil K.
Sachdev
and
Michael
M.
Fe-Ni-C
AUSTENITE
Shea, Metallurgy Department,
General Motors Research Laboratories, Warren, MI Twinning
observed
in
an
Fe-15
DURING
Ni-O.8
C
48090-9056
alloy
deformed at
elevated temperatures is a direct consequence of dynamic strain aging caused by carbon interacting with dislocations. Serrated flow and periodic increases in stress are observed as a result of this interaction and each increment in stress is believed to raise the overall stress to that necessary for twinning. Twinning, instead of the normally observed additional dislocation generation, provides the stress relief after each periodic stress rise, and becomes an alternate mode of deformation once slip becomes difficult. The presence of carbon appears to be necessary to indirectly promote the twinning process. An enhanced ductility is associated with the twinning process.
(8:50 a.m.) MICROSTRUCTURE AND HIGH TEMPERATURE PROPERTIES OF A MAGNESIUM20.0 WT% GADOLINIUM ALLOY: F.C. Grensing and H.L. Fraser, Univ. of III inoi s, Urbana, IL 61801. Rare earth alloy additions have been shown to increase the useable upper temperature 1 imit for magnesium alloys without i ncreas i ng the alloy den s ity to unacceptable 1 eve 1 s. The elevated temperature tensile properties of a magnesium-20.Owt% gadolinium alloy have heen examined. Microstructural characterization using analytical electron microscopy techniques were conducted on all specimens to determine the structure and any changes that occurred during heat treating and testing.
(9: 10 a.m.) EFFECTS OF COBALT AND ORIENTATION ON YIELDING IN A SINGLE CRYSTAL SUPERALLOY: G. E. Bobeck, Un i vers ity of Idaho. l~oscow, I D 83843; f!ASA Lewi s Research Center, Cl evel and, OH 44135.
~ine!:.>
Compressive yield stress has been studied as a function of crystal orientation in aNi-base superalloy similar tl' Mar-M247 with either 5 or 10 Co (w/o). r~icrostructure was only sl ightly affected by Co concentration. Noticable was that the 5 Co alloy contained slightly more y' than the 10 Co alloy. In both alloys, Co partitioned about 2.8:1 to the y matrix. At 760"C, where some superalloys exhibit complicated yielding behavior, Schmid's LaVi was Vlell obeyed, and the CRSS for primary octahedral sl ip was about 10% higher for the 5 Co alloy than the for 10 Co alloy. The CRSS for cube sl ip in spec imens with axes near
was 1 ittle affected by Co level. Thus, the CRSS for octahedral sl ip increased relative to that far cube sl ip ~Iith decreasing Co concentration. It is also shown that data on other Ni-base superallays and y' in the 1 iterature appear to show the same trend. Results are discussed in terms of recent theories of yielding of single phase y' and nickel-base superalloys.
(9:30 a.m.) HOT DEFORMATION AND TEXTURE IN NEODYMIUM-I RON-BORON PERMANENT MAGNETS: R. K. Mishra and R. W. Lee, Physics Department, General
Motors Research Labora tor ies, Warren, MI
melt-spun, Nd-Fe-B ribbons. Transmission electron microscopy study of fully dense magnets shows that the microstructure of these magnets consists of parallel platelets of defect-free Nd Fe 4B grains wi th their c-axes normal to the platelet surface. 2 These 1 grains are surrounded by a small amount of an intergranular phase of approximate composition Nd Fe • It is established that 7 during hot deformation, (uniaxial 3 c6mpression at -700°C) (a) material flows radially from the center of the sample to the periphery; (b) each of the grains in the sample, both at the center and at the periphery, are flattened; and (c) these grains are rotated so as to have their c-axes parallel to the press direction. Flattening of the grains and their rotation occur due to motion of glide dislocations on (001) planes. Formation of a Nd-rich liquid phase during hot deformation assists in mass transport and material flow.
(9:50 a.m.) MICROSTRUCTURAL INVESTIGATION OF COLD-WORKED Cu-Nb in situ COMPOSITES:* A. R. Pelton, F. C. Laabs, C.-C. Cheng, E. D. Gibson and J. D. Verhoeven, Ames Laboratory-USDOE, Iowa,State University, Ames, rA •
The microstructures of cold-worked Cu-20 wt.% Nb in situ composites were studied by scanning and transmission electron microscopy. Selective etching techniques allowed extraction of Nb filaments from wire and sheet material after various stages of deformation. These filaments contain regions with low dislocation densities which are separated by grain boundaries. The boundaries are aligned with the fiber axis and have relative misorientation angles of < 2 0 to 35 0 with a predominant tilt component. Examination of transverse sections of composite wires reveals that the Cu matrix also has a surprisingly low dislocation density. These results suggest that these composites recover dynamically above a critical level of deformation. The ramifications of these findings on the mechanical properties of these alloys will be discussed. *Work was supported by USI)OE, Office of Basic Energy Sciences, Div. of Materials Sciences, under contract No. W-7405-Eng-82.
(10: 10 a.m.) Subgrain Growth in Al-0.2 Mg Alloy During Recovery: Karen P. Martin and S.K. Varma, Department of Metallurgical Engineering, The University of Texas at El Paso, El Paso, Texas 79968. The cold drawn wires of Al-0.2 Mg alloy with true wire drawing strains of 0.55 and 1.47 were subjected to recovery process during static annealing at two different temperatures, 250 and 300't. The subgra ingrowth cha racteri st i cs duri ng recovery has been stUdied. The mechanism of subgrain growth, as revealed by plotti ng squa re of the subgra ins i ze as a function of ti me of annea ling at a given temperature, has been compared with the results obtained earlier on pure aluminum and Al-0.6 Fe alloy. The subgrain growth mechanism will be discussed in terms of coalescence and boundary migration.
(10:30 a.m.) CONSTANT SUBSTRUCTURE CREEP OF METALS: J. C. Gibeling, Division of Materials Science and Engineering, Department of Mechanical Engineering, University of California, Davis, California 95616. Data obtained primarily from stress reduction experiments are used to describe the creep behavior of metals under conditions of constant dislocation substructure. The materials which were investigated include AI, Cu and Fe. It is demonstrated that these constant substructure data are best described by an exponential dependence of strain rate on stress. This finding is in contrast to the roore common description of such measurements based on a power law with a stress exponent of 7 or B. These results suggest that the constant substructure behavi or can be interpreted in terms of a k i net i claw for thermally activated rootion of dislocations through a fixed obstacle structure. The activation enthalpy for this process
is computed for several testing conditions.
(10:50 a.m.) EVOLUTiON OF DISLOCATiON STRUCTURES DUR[NG HIGH TEMPHA'lUKE L. L. Lisiecki and J. R. Weertman, Dept. of Mat. Sci. & Engr. and Mat. Res. Ctr., Northwestern University, Evanston, 1L 60201 FATIGUE OF COPPER SINGLE CRYSTALS:""
The evolution of dislocation structures formed during high
temperature plastic strain-controlled fatigue of copper single crystals will be examined by TEM on varioub crystal planes. Effects of temperature and plastic strain amplitude will be discussed. Dislocation structure evolution will also be correlated with the observed mechanical behaviorH of hardening, softening and saLuration.
48090-9055.
Hot-pressing and hot deformation (die-upsetting) are necessary steps in preparing fully dense aligned magnets from amorphOUS,
-:
Owens-Corning fiberglas fellowship.
TMS Annual Meeting 7 (11: 10 a.m.) MICROSTRUCTURAL STUDY OF M-\.CROSCOPIC SHEAR BANDS FORMED DURING PLANE STRAIN THINNING OF AL·MG SHEET, J.E. Bird, K. E. Newman, J. M. Carlson, and K. Narasimhan, School of Materials Engineering, Purdue University, W. Lafayette, IN 47907. AI-4.4'CMg-0.4"OMn alloy sheet fails in plane strain thinning by the loealizat.ion of plastic flow into shear bands which grow across thousands of grains. The purpose of this investigation was to determine experimentally, from observed microstructural changes, how macroscopic sl,ear bands develop during plastic flow of a commercially produced aluminum alloy. Through-thickness necking precedes macroscopic shearing when alloy 5182-0 undergoes plane strain stretching. During necking the microstructure rotates and gradients of shear strain develop as a geometric consequence of necking itself. Macroscopic shear bands initiate in surface grains at. sites within the neck where rotation of microstructure and shear strain are large. As necking continues macroscopic shear bands grow into the sheet interior. Much of the thinning that takes place within a. localized JlPck is produced by macroscopic shearing. Geometric softening, due to loss of CfOSS sectional area on one side of the shear band, i('ads to a gradient of st ress and to motion of the zone of shearing.
(9:30 a.m.) THE EFFECTS OF MICROSTRUCTURAL VARIABLES ON THE WORK HARDENING AND THE DUCTILITY OF DUAL-PHASE STEELS, W. S, Owen, Massachusetts
Institute of Technology, Cambridge, Massachusetts Recent work has demonstrated the profotfnd effects on mechanical properties which can be produced by changing the microstructure of dual-phase steels. Three microstructures are of special interest - those produced by intercritical annealing ferritepearlite, or lath martensite, or austenite - and the discussion will be confined to these. A model which, it is believed, provides a satisfactory explanation of the unusually high work
hardening rate at small deformations will be outlined.
This
model incorporates two phenomena: long-range internal back stresses and heterogeneous, extrinsic transformation deformation of the ferrite. Finally, ways in which the known structureproperty relationships in dual-phase steels can be used to design steels for specific applications will be considered.
(10:00 a .m,) DESIGN AND PROCESSING OF HICROALLOYED HSLA STEELS:
(11 :30 a.m.) INITIATION AND GROWTH OF MACROSCOPIC SHEAR BANDS. DUHl:'-iG PLANE STRAIN THINNING OF AUSTENITE-FERRITE SHEET, J.M. Carlson and J.E. Bird, School of Materials Engineering, Purdue University, W. Lafayette, IN 47907. This is a quantitative, experimental study of shear flow that develops during through-thickness necking while sheet thins under plane strain conditions. r..-1easurements are reported of rotation of miC'rostructure due to through-thickness necking 0, shear strain throughout the neck 1, and von Mises effective strain, within the neck. Gradients of shear strain develop within the neck as a geometric consequence of necking. Macroscopic' (sample-scale) shear bands initiate in surface grains at sites within the neck wherE' rotation of mi(,fostrurture () and shear strain 1 are Jargpst; and not where effecti\'C strain, is highest. Growth of macroscopic shear bands into the sheet interior is constrained by the need for accommodating deformation in other parts of the neck. Catastrophic sheet failure develops onr(' now throughout the sheet localizes into one (;r more shear bands that collectively penetrate from one sheet surface to the other.
EARL R. PARKER SYMPOSIUM ON STRUCTURE/PROPERTY RELATIONSHIPS: MICROSTRUCTURE AND MECHANICAL PROPERTIES I Sponsored by The Mechanical Metallurgy, Structural Materials and Physical Metallurgy Committees of TMS-AIME Monday, March 3,1986 Mardi Gras D 8:30a.m. Marriott Hot~1 Session Chairmen: Stephen D. Antolovich, Fracture and Fatigue Research Laboratory, Georgia Institute of Technology, Atlanta, Georgia 30332-0100, Robert o. Ritchie, Department of Materials Science and Mineral Engineering, University of California, Berkeley, California 94720
PoL. Hangonon,
Mechanical Engineering Department. Florida Institute of Techno logy, Melbourne, FL. Micro-a lloyed HSLA stee Is derive their favorab Ie propert ies from ferrite grain size refinement, precipitation hardening and from their inherent ly low carbon content between 0.05 and 0.10% C. The microalloying elements are usually niobium (columbium), vanadium and titanium but one may add to these boron. Although good properties are obtained by sing Ie additions of the elements, opti.naJm properties are obtained by adding two or more elements. For example, boron can only be used effectively with titanium. In addition to control of composition, careful control of thenoo-mechanical processing during hot-rolling plays a significant role in attaining the desired properties.
(10:30 a.m.) FRACTURE TOUGHNESS OF ELECTROSLAG WELDMENTS IN STRUCTURAL STEELS: William E. Wood, Professor and Chairman, Dept. at Matis. Sci. and Eng., Oregon Grad. etr., 19600 N.W. Von Neumann Dr., Beaverton, OR 97006-1999 The electroslag process as applied to thick section weldments presents unique challenges to Materials Scientists, Welding Engineers, and Design Engineers alike. This paper presents results on an ongoing program to improve the tracture toughness and fatigue properties at 2 and 3 inch thick A36 and A588 electroslag weldments by moditying both chemistry and process parameters. Alloy modifications include Ni, Cr, Mo and Mn. Process modifications are utilized to intluence the solidification rate and process by limiting heat input and altering the solidification behavior. Process control modifications are designed to minimize the formation at defects such as lack of fusion, slag entrapment, and ferrite vein cracking. Fracture toughness evaluation is being ccrried out by both Charpy impact and plane strain fracture toughness testing. Full scale 24 foot long I-beams are being tested to evaluate the fatigue behavior of the weldments. The results are analyzed with respect to alloy chemistry, microstructure, and process parameters.
(11 :00 a.m.) THE MICROMECHANISMS OF DUCTILE FRACTURE AND THE DESIGN OF ULTRA
HIGH STRENGTH STEELS: W. M. Garrison, Jr.. Carnegie-Mellon Uni versity, Pit tsburgh, PA.
(8:30 a.m.) PROF. EARL R. PARKER: IN RETROSPECT: V. F. lackay, President, Materials and Methods, 1014 West Rd., New Canaan, CT 06840 Science technology and engineering have been enriched by the contributions at Prot. Earl Randall Parker, his students and his colleagues. Ferrous and non-terrous metals, superolloys, precious metals and physical ceramics-all have been the subject of investigations characterized by his intuitive grasp of physical laws and phenomena and by simple but elegant experiments designed to define and illustrate them. The dimensional spectrum of his work ranges from the atomistics of dislocations to the multi-micron level of metallic and non-metallic microstructures and, perhaps unexpectedly, to the macro-dimensions of full-scale ship hatches. A partial but representative listing of the specific materials investigated by Prof. Parker, at either the General Electric Laboratory or the University at California, Berkeley, might include, tor example, single crystal high purity ceramics, transition metal-interstitial element superconducting compounds, spinodal binary precious metal alloys, superalloys and ultra high strength steels. These few examples suggest a rich diversity, a challenging complexity and the implicit rejection of subjective "pure vs. applied" science boundaries. In this paper, a chronological review (five decades) of Prof. Parker's contributions to materials science will be attempted.
The approach taken here in describing ductile fracture of steels is that voids grow initially at sulfide inclusions and that fracture occurs when these voids coalesce through processes of void sheet coalescence or strain localization or both. For conditions ahead of an initially sharp crack, this approach leads to a prediction that the critical crack tip opening displacement at fracture, 0IC' will scale as Xo(Rv/Rr), where Xo is the average sulfide spacing and (Rv/Rr) is an average of the radius of a void (RV) nucleated by a sulfide divided by the radius of the sulfide (Rr) nucleating the void. The data indicate that" (~/Rr) is determined by the yield strength and fine scale microstructure but is not a function of Xo' This suggests to improve toughness two distinct alloy design methodologies are possible - one to increase Xo and the other to control the fine scale microstructure to maximize (Rv/Rr). Examples of both methodologies will be presented and ongoing efforts in these areas will be discussed.
(11 :30 a.m,) THE DESIGN OF LOW ACTIVATION MARTENSITIC STEELS FOR FUSION ENERGY
APPLICATIONS: * T. Lechtenberg I Materials and Chemist ry Division, GA Technologies Inc., PO Box 85608, San Diego, CA 92138
(9:00 a.m.) UNDERSTANDING AND CONTROLLING THE DUCTILE-BRITTLE TRANSITION IN STEELS: J_ W. Morris, Jr., Department of Materials Science and Mineral Engineering, University of California 94720. ABSTRACT NOT AVAILABLE
Structural materials used in fusion reactors will be exposed to an intense flux of 14MeV neutrons so they must be highly radiation damage resistant. The Cr-Mo steels are one promising class being considered. To achieve fusions' full attractive environmental potential, the residual activation of structural materials must be minimized and elements used in the Cr-Mo steels for elevated temp-
8 TMS Annual Meeting erature strength (eg. Mo and Nb) are proscribed in order to reduce the long-term activation. Because W behaves similarly to Mo in equal atomic fractions, a series of steels containing 9-11% Cr have been melted substituting 2.5%W for l%Mo. For a fully martensitic structure and to prevent weld cracking, 0.15% C was added. Small additions of V (to O.3wt%) and Ti (to O.lwt%) were used to enhance the microstructural stability. Several of these steels
have been irradiated at 693, 773 and 873 K.
Microstructural obser-
vations and the alloy development optimization plan are discussed.
*Research is supported by DOE under contract DE-AT03/84ER53158.
(11: 00 a.m.) GROUP IIIB HALOMETALLOPHTHALOCYANINES AND RELATED MACROCYCLES, David C. Weber and Lissante LoBianco, Chemistry Division (Code 6137), Naval Research Laboratory, Washington, DC 20375-5000 Compounds of the type PcMX where Pc = phthalocyanine and M = AI, Ga, In h ave shown high conduct i vit i es when doped with appropriate oxidizers. The fluorides have exhibited higher conductivities than the corresponding chlorides. This is a result of the results of the crystal structures wi 11 be discussed to explain conduct i vity differences. Recent work has concentrated on formi ng ana logou s compounds with an extended organi c ring sys tern. Results of our synthetic work as well as electrical characterization of the materials will be presented.
PROPERTIES OF ORGANIC I:
Mardi GrasC Marriott Hotel F. E. Stafford, National Science FoundaDivision of Materials Research, Rm. 404, Washington, DC 20550
(8:30 a.m.) CHEMI CAL ARCH ITECTURE OF ORGAN IC CONDUCTORS ,Dwai ne 0 .. Cowan, Dept. of Chemistry, Johns Hopkins University, Balt1more, MD 21218 A descri pt i on wi 11 be presented of how donor and acceptor structural variations affect the electrical conductivity and Tc of organ i c metals and superconductors.
(9:00 a.m.) NOVEL SULFUR-BASED ORGANIC SUPERCONDUCTORS*, Jack M. Williams, Chemistry and Materials Science and Technology D1v1s10ns, Argonne Nat ional Laboratory, Argonne, IL 60439 Although elemental sulfur is an electrical insulator, a new class of S-containing organic compounds based on BEDT-TTF, Fig. I, form novel organic conductors and superconductors. The chemistry, electrical properties, and physical properties of these systems will be discussed.
~XS1S>=
SS
S
S
H
ENVIRONMENTAL EFFECTS I TMS-AIME General Abstract Session Monday, March 3,1986 Mardi Gras A·B 8:30 a.m. Marriott Hotel Session Chairman: M. J. Kaufman, National Bureau of Standards, Gaithersburg, MD 20899
(8:30 a.m.) FRACTURE AND FATIGUE CRACK PROPAGATION BEHAVIOR IN 3Cr-ll;;Mo-INi PRESSURE VESSEL STEEL WELDMENTS EXPOSED TO HIGH TEMPERATURE/HIGH PRESSURE GASEOUS HYDROGEN:* R. H. Dauskardt, E. R. Parker and R. O. Ritchie, Department of Materials Science and Mineral Engineering, University of California, Berkeley, CA 94720. A new series of 3Cr-Mo-Ni thick-section pressure vessel steels, to replace 2~Cr-lMo, has been developed with superior strength, toughness and resistance to hydrogen attack. In the present work, fracture toughness (JR(6a) curves) and resistance to fat i gue crack growth are exami ned in thi ck -sect i on we 1dments of a 3Cr-ll;;Mo-INi composition following prolonged exposure to high pressure/high temperature gaseous hydrogen. Specifically, behavior in the highly susceptible regions of the heat-affectedzone and in the less susceptible weld metal are compared with prior data in parent plate material, with a view to isolating the microstructural features which are responsible for promoting envi ronmenta 1 damage. *Sponsored by the Department of Energy, Advanced Research and Development Fossil Energy Materials Program.
(8:50 a.m.) THE INFLUENCE OF INCLUSION MORPHOLOGY IN HYDROGEN RELATED PROBLEMS IN LOW SULFUR CLEAN STEEL: s. Protasio and G.R. St.Pierre, Dept.
of Metallurgical Eng., Ohio State Univ., 116 W 19th Avo, Columbus
Figure 1 BEDT - TTF
*Research performed under the auspices of the Office of Basic Energy Sciences, Div. of Materials Sciences, US DoE.
(9:30 a.m.) MAGNETICALLY lNDUCED PHASE TRANSITIONS IN CHARGE TRANSFER SALTS Paul M. Chaikin, Dept. of Physics, University of Pennsylvania, Philadelph1a, PA 19104
OH 43210 Hydrogen embrittlement(HE), hydrogen induced cracking and other hydrogen related problems can occur in low sulfur clean steel. For this case, the mechanisms are not well understood but steelmakers have accumulated considerable practical evidence that an increase in the sulfur content, under certain conditions, can reduce the detrimental effects of hydrogen. It has been postulated that, in clean steel, decreased void volume and inclusion/matrix interfacial area can create a severe localized hydrogen accumulation and effective pressure at critical sites. To study the influence of inclusion morphology on HE and HIe, tensile samples of low sulfur corrunerclal steels were charged with hydrogen at high pressure and temperature or through fused salts. For each sample, the chemical composition, morphology and size distribution of inclusions were studied by means of scanning and transmission microscopy and stereo logy operations in a Videoplan system. The samples were mechanically tested and the fracture surfaces were studied by scanning microscopy to observe the development of cracks around inclusions. Mechanisms of failure are postulated.
(Abstract not available) (9: 10 a.m.)
(10:00 a.m.)
BREAK
(10:30 a.m.) PRESSURE IN THE STUDY OF ORGANIC SUPERCONDUCTIVITY, J.E. Schirber, L.J. Azevedo, J.F. Kwak, E.L. Venturini, P.C.W. Leung, M.A. Beno, H.H·. Wang, and J.M. Williams, P.O. Box 5800, Sandia National Laboratories, Al burquerque, NM 87185 Pressure has been an important parameter in the study of organic superconductivity. In many of the compounds found to date, pressure is required to suppress metal-insulator transitions to low enough temperatures to allow superconductivity. Recent 1y, we have shown that the high T (8K) superconduct i ng state of e-(BBDT-TTF)213 is formed by a combination of shear and hydrostatic pressure and cannot be accessed by pressure alone. Structural models consistent wilth these findings are evolving.
EFFECT OF SULFUR CONTENT ON HYDROGEN EMBRITTLEMENT IN LOW ALLOY STEEL: Lisa DuVernay, and G.R. St.Pierre, Dept. of Metallurgical Engineering, Ohio State Univ., 116 W.19th Ave., Columbus,OH 43210 With increased emphasis on the production of cleaner, low sulfur steels, hydrogen embrittlement has become a problem of considerable concern. The tendency of selected low sulfur steels to form hairline cracks, or fisheyes, and become irreversibly embrittled when charged with hydrogen has been examined. Two steels with different sulfur contents, 0.003%S and 0.024%S, were charged in hydrogen gas at different temperatures and different hydrogen pressures. The tensile properties were measured directly after charging, after selected incubation periods, and again after extended holding times up to 120 hours. Preliminary results show that the tensile properties of both steels after charging are equally degraded, but after holding for 120 hours the higher sulfur steel returns to its pre-hydrogen·charged mechanical properties, while the ·low sulfur steel does not regain its original ductility. In view of the new experimental evidence, possible mechanisms for the irreversible damage are proposed and discussed.
TMS Annual Meeting 9 (9:30 a.m.) HYDROGEN EMBRITTLEMENT IN Ni AND Ni/Cu ALLOYS*: S. M. Field, W. K. Blanchard and L. A. Heldt, Department of Metallurgical Engineering, Michigan Technological University, Houghton, MI 4'3931
Hydrogen embrittlement (liE) of pure nickel and nickcl-cOIJJ'cr alloys has been investigated using in-situ cathodic charging during slow strain rate testing. Subsequent x-ray diffraction was employed to analyze the reSUlting structurE' of the alloys after W1derqoing hydrogen charqing. The results of mechanica 1 testing and diffractometry were correlated to elucidate the effects of copper on the kinetics and thermodynamics of HE.
*Research sponsored by Department of Energy_
(9:50 a.m.) HYDROGEN EFFECTS ON STRAIN LOCALIZATION IN SPHEROIDIZED STEELS: I.-C. Park and A.W. Thompson, Dept. of Hetallurgical Engineering and Materials Science, Carnegie-Mellon University. Pittsburgh, PA 15213.
Measurements during the microvoid coalescence stage of ductile fracture of tensile and notched bend specimens of spheroidized 1520 steel have shown that hydrogen-induced accelerations in void growth and in strain localization contribute to losses in ductility. These results are consistent with other recent studies showing that hydrogen effects can be predominantly on local plastic phenomena during fracture. This research was supported by NSF grant DHR 81-19540.
(10: 10 a.m.) Hydrogen Induced Fracture Mode Changes in a Nickel Base Super alloy Single Crystal, J. Chene*, l. M. Bernstein, and J. C. ~~illiams. Dept. of Met~. and Matls. Science, CarnegieMellon University, Pgh, PA, *now at the Univ. of Paris-Sud. Orsay France.
:11: 10 a.m.) THERMODYNAMIC AND KINETIC MODELING OF SENSITIZATION IN AUSTENITIC STAINLESS STEELS:* T.Arul Mozhi, W.A.T. Clark, B.E. Wilde, Dept. of Met. Eng., Ohio State Oniv., Columbus, Ohio 43210. Theoretical models used to calculate: 1) time-temperature-sensitization (rrS) diagrams, 2)i chromium concentration at the carbide-austenite interface (x Cr)' and 3) chromium concentration profiles in the vicinity of carbides, as a function of alloy composition and sensitizing temperature and time for AISI 304 and 316 stainless steels, show that sensitization is retarded with decreasing carbon and increasing nitrogen levels. The calculated and experimental TTS diagrams obtained using the electrochemical potentiokinetic reactivation (EPR) tests and the modified Stra~ss test are compared, as are calculated and experimental x and chromium concentration profiles obtained using the analyfrcal electron microscope (AEM). The calculations and AEM results are correlated with the corrosion behavior of the alloys. *Thi s work was supported partly by the Dept. of Energy under Contract IDE -AG02-81ER10972, and the Lawrence L1 vermore Na ti ona 1 Labora tory.
(11 :30 a.m.) ELLIPSOMETRIC STUDY OF THIN FILM OXIDATION OF POLYCRYSTALLINc
AND SINGLE CRYSTAL IRON: S. T. Rosinski, Sandia National Labs, Div. 7263, P.O. Box 5800, Albuquerue, NM 87185, w. N. Weins & D. L. Johnson, Dept. of Mech. Engr., UniverSity of Nebraska, Lincoln, NE
68588-0525
The early stages of oxidation of high purity polycrystalline and single crystal iron in air at 25°C was studied using ellipsometry. Polycrystalline iron was found to obey a logarithmic rate law for the growth of the oxide identified as Fe 0 with a 3 4 mean film thickness of 16 A after approximately 5 hrs. An iron single crystal of (Ill) orientation, grown by the strain-anneal method, was found to follow a parabolic growth rate law with a maximum film thickness of 6.3 A after 5 hrs. This crystal exhi bi ted a faster rate of oxidation and the data suggest that the oxide is a mixture of Fe 0 and Fe 0 - Optical properties 2 3 3 4 for the substrate and oxide of both samples were also measured_
The introduction of hydrogen has been shown to degrade the tensile and fatigue properties of the nickel base superalloy single crystal alloy CMSX-2. The degree of embrittlement scales with the depth of the hydrogenated layer and this depth is controllable by the charging conditions and specimen geometry.
Accompanying
~he
embrittlement is a change in fracture mode in
<]01> oriented crystals from a fracture path parallel to (111) planes to one parallel to (100). These results will be descrihed in terms of hydrogen partitioning among various internal traps, in particular the -yIY' interface, and the affect of hydrogen on dislocation behavior.
(10:30 a.m.) THE EFFECT OF HYDROGEN ON FRACTURE TOUGHNESS OF
SUPERALLOY: ~ational
AN IRON BASED
N. R. Moody, R. E. Stoltz and M. W. Perra, Sandia
Laboratories, Livermore CA 94550
Fracture toughness was determined in the Fe-Ni-Co super alloy I~903 as a function of hydrogen concentration and grain size. Tests using precharged, precracked three point bend samples 1/2 showed that fracture toughness decreased from 100 to 50 MPa-ffi as hydrogen concentration increased from zero to 5000 appm. Tests on samples with 5000 appro also showed that fracture toughness was independent of grain size. In all samples, fracture initiated at the matrix carbides which resulted in welldefined slip band fracture in samples with hydrogen concentrations greater than 500 appm. The effect of hydrogen on fracture toughness will be explained by the relationship between the microstructure, slip band formation and the effect of hydrogen on slip band fracture. Work supported by DOE.
(10:50 a.m.) EFFECTS OF TRAPPING ON HYDROGEN EVOLUTION FRml
IRON*: K. Hashimoto a.nd M. rleshii, l'1aterials ResE'arch Center (-lnd Depart=ment of rlaterials Science anel. Engineering, NorthvJestern Universi ty, Evanston, IL 60201 USA
It has been shown in our pn"vious report that the evolution of trapped hydrogen occurs at a temperature considerably higher than that of free hydrogen. The trapped hydrogen, therefore, can be studied by examining the high temperature peak of hydrogen evolut ion in iron. The t rapping of quenched-in hydrog0n by grain boundaries was examined as a function of quenching temperature, i.e. hydrogen concentration. It was found that the amount of trapped hydrogen increased rapidly with hydrogen concentration oJ::x:we the critical concentration. The hydrogen tra,rr ping was more pronounced when the charging was carried out electrochemically even in single crystals. The trapped hydrogen increased significantly with charging current. The nature of the traps and the implication of the present observation on earlier works will be discussed. *Sup[X)rted by the NSF-tlRL program through the tlaterials Research Center of Northwestern University (Grant No. EllR82-l6972)
EXPERIMENTAL METHODS-JOINT SESSION-ON MICROGRA VITY MATERIALS SCIENCE RESEARCH AND HIGH TEMPERATURE SCIENCE I Sponsored by the ASMIMSD Thermodynamic Data Committee Monday, March 3, 1986 Mardi-Gras F-G 8:30a.m. Marriott Hotel Chairman: R. A. Schiffman, Midwest Research Institute, Kansas City, Missouri 64110 Session Chair: F. Kohl, NASA-Lewis Research Center, Cleveland, Ohio 44135
(R:l0 a.m.) EXPERIMENTAL TECHNIQUES AND METHODS IN HIGH TEMPERATURE SCIENCE FOR MICROGRAVITY MATERIALS SCIENCE RESEARCH After th~ evocation of the rirst instrumen-;:; generation (Gradient lJeating Facili ty - said GHF) developped for Spacelab programs we give new tendancy on space hardware developments linked with french and european scientific projects in the field of material SClence like the growth from the melt bath or from vapour phase. We discuss recent improvements developped at the occasion of scientific projects such as MEPHISTO, the french programme on directional sol idification stabi 1 i ty study under micrograv (CEA/CNES/NASA cooperation) and ESA programmes concerned such IML/D2/ Advanced GHF or EURECA for long duration experiments 1 ike vapor phase gro'w·th experiments. Design and performances in Bridgman-Stockbarger directional sol i di fica ti on are gi ven in terms, of high thermal gradi ents achievables, thermal gradient stabili ty, back-melting mastering, quenching ca~abilities, heat sources thermal field using heat pipes. In-5i tu measurements (Seebeck marking are also evoked.
(9:00 a.m.) LASER INDUCED VAPORIZATION MASS SPECTROMETRY OF REFRACTORY
MATERIALS:* P.K. Schenck, D.W. Bonnell, and J.W. Hastie, Inorganic Materials Division, National Bureau of Standards, Gaithersburg, MD 20899 A Laser Induced Vapori zation Mass Spectrometer has been developed by coupling a high power pulsed Nd/YAG laser to a
10 TMS Annual Meeting hi gh pressure sampl ing - mass spectraneter. The pul sed laser heats the sample surface, and the vaporized species expand into the differentially pumped vacuum of the mass spectrometer forming a molecular beam, The molecular beam is ionized by electron impact and mass analyzed using a quadrupole mass ctrometer. Mul ti pIe pulses of the laser are used for cessive heating experiments and the Signals are averaged to provide time-resel ved data on each of the individual species resulting from the vaporization process. This technique has wide potential for high temperature studies of refractory materials since troublesome container-sample reactions are a voi ded. The techni que has been demonstrated on boron ni tr i de H:~999~2_~,!9_6r!,p!:,g~ (T-4000K) samples. This work supported in part by DNA and AFOSR
A SYSTEM FOR CONTROL AND MANIPULATION OF REDOX CONDITIONS IN MICROGRAVITY EXPERIMENTS: R. J. Williams, NASA-JSC, Houston, TX; G. D. Jolly, A. B. Lanier, and W. I. Carter, Lockheed Engineering and Management Servi ces Co., Hous ton, TX Hi gh- tempera ture s tudi es of. many gl ass and cerami c sys tems require control of the oxygen fugacity, but reduced-gravity experiments on such systems are diffi cult since conventional techniques (e.g., gas mixing) are not easily adaptable to use in space. A system employing solid-ceramic electrolyte cells 'to control, measure, and manipulate redox conditions has been designed, built, and tested; it should be adapted easily to Shuttle or Space Station use because it is small and totally recyc 1es a 11 gases. The redox condit ions a re produced and maintained by using the ceramic cell to electrolyze the gas in contact with the experiment. The system operates well between 770K and 1120K at oxygen fugacities between those of the NiNiO and Fe-FeD reactions. Control of temperature, oxygen fugac ity, and ra te of change of these va ri ab 1es with time is provided; accuracies are similar to those obtained with conventional systems.
(11:25 a.m.) GROWTH OF SYNMETALS UNDER MICROGRAVITY USING OPPOSITE ORIENTED DIFFUSION: K.F. Nielsen and * M.D. Lind, Technical University of Denmark. In connection with a basic research program on synthetic metals (organic crystals with low dimensional metallic conductivity) a European Space lab experiment aimed at crystal growth of TTF-TCNQ was sporsored by the Danish Space Board. The method investigated was opposite oriented diffusion (OOD) at low temperature (40 0 C). This method was previously tried successfully with non-synmetal crystals as part of the Apollo-Soyuz Test Project. For various reasons the Space lab experiment failed to produce synmetals, but the OOD-method again showed potential for being an efficient method for producing highly perfect crystals of this type. We shall report on growth experiments with TTF-TCNQ, PbS, and CaC0 3 performed on the Long Duration Exposure Facility, launched in April, 1984. Further experiments with TTF-TCNQ and related compounds are planned for the European Retrievable Carrier. * On leave from Rockwell Int. Science Cetlter, Ca.
HIGH TEMPERATURE ALLOYS I: Non-Optimum Microstructures in Superalloys Sponsored by the TMS High Temperature Alloys Committee Monday, March 3,1986 Acadia 8:30 a.m. Marriott Hotel Session Chairmen: D. L. Anton, United Technologies Research Center, East Hartford, CT 06108; K. A. Green, Allison Gas Turbine Division, Indianapolis, IN 46206
(9:50 a.m.) A MODULATED FAST FLOW, THERMIONIC EMISSION TECHNIQUE FOR HIGH TEMPERATURE SURFACE REACTIONS: B.L. Halpern, Department of Chemical Engineering, Yale University, Box 2159 Y.S., New Haven, CT. A modulated fast flow method employing an oscillating needle gas source has been developed for measuring the rates of fast surface reactions in a transient mode at p....., 1 torr or greater. The technique has been used to study the rate of deposition of cheu,.isorbed carbon on hot platinum (T""" 1000Q C) by decomposing organic molecules. The rate of carbon coverage increase is measured by following the thermionic emission of electrons; a monolayer of carbon enhances emission one-thousandfold. Rates of deposition were determined for straight chain alkanes from methane through octane, and were found to increase sharply with the number of atoms in the carbon chain. The oscillating needle gas source and modulated fast flow technique will be described and the advantages of the method will be discussed.
(10:15 a.m.)
(8:30 a.m.) THE CONTINUING BATTLE AGAINST DEFECTS IN NICKEL-BASE SUPERALLOYS: Robert L. Dreshfield, NASA Lewis Research Center, Cleveland, OH 44135. In the six decades since the identification of age nardenable nickel-base superalloys their compositions and microstructures have changed markedly. Current alloys are tailored for specific applications. Thus their microstructures are defined for that application. This paper will briefly review the evolution of superalloy microstructures and comment on the appearance and i mpl i cati ons of mi cros tructura 1 defects in high performance superalloys. It is seen that new alloys and processes have generated new types of defects. Thus as the industry continues to develop new alloys and processes it must remain vigilant toward the identification and control of new types of defects.
BREAK (9:10 a.m.)
(10:35 a.m.) LABORATORY IN SPACE, HOW CLOSE WE ARE: Wubbo J. Ockels, c/o DFVLR, I inder Hohe, 5000 Koln 90, West Germany Tne author lS involved in the SpacelaB program since 1977 and has flown with the Spacelab 0-1 Mission. Presented are results concerning ,4-gravity material science experiments performed on SL-l and 0-1. Lessons learned from these Spacelab flights and guidelines for future space laboratories, e.g. Space Station, are discussed.
(11 :00 a.m.) HTFFR EXPERIMENTS ON METAL ATOM AND RADICAL OXIDATION REACTIONS OVER WIDE TEMPERATURE RANGES: .Arthur Fontijn, Department of Chemical Engineering & Environmental Engineering, Rensselaer Polytechnic Institute, Troy, NY 12180-3590. The development and use of the HTFFR (high-temperature fast-flow reactor) technique is described. It is leading to an experimental data base for homogeneous gas-phase oxidation reactions of refractory species. Measurements of rate coefficients k(T) in the 300-1900 K range for reactions of metal atoms and metal monoxides and halides are reported. A variety of k(T) dependences on Tare observed. These include normal Arrhenius k(T) = A exp( -EA/RT) behavior, temperature independent rate coefficients and reactions with a slight negat..ive activation energy. In addition, reactions have been found, tHe rate of which is primarily determined by the thermal equilibrium population of excited states of the reactants. Several of the observations discussed are a posteriori understandable, but were not predictable and in several instances were unexpected.
Work supported by the Air Force Office of Scientific Research under grant AFOSR 82-0073
THE INFLUENCE OF COOLING RATE AND y' PRECIPITATION ON THE CREEP AND STRESS-RUPTURE PROPERTIES OF RENE' 95: P. R. Showal, E. L. Raymond, Cameron Iron Works, Inc., Houston, TX 77251. The pre-age solution treatment of Rene' 95 involves variables that strongly influence the creep and stress-rupture properties. The role of these variables recognized as solution temperature, transfer time from solution to quench media and the associated cooling rates was examined by correlating the thin foil TEM microstructure and the creep and stress-rupture resistance. A fast kinetics of y' precipitation rendered the nature of the cooling y' (i.e., the y' precipitated during transfer time) strongly dependent on solution temperature and cooling rate. The evolved variability in cooling y' along with a relatively less important second effect arising from its influence on the aging y' precipitation potential were cons i dered to alter s i gnifi cantly the creep and stress-rupture resistance. The monotonic properties were not affected in any important manner. These inter-relationships among solution parameters, mi crostructures and properti es were di scussed and certain structure-property correlations were established.
(9:35 a.m.) THE KINETICS AND MECHANISMS OF HIP CONSOLIDATION OF A NICKEL-BASE
SUPERALLOY:* J.C. Borofka, S.V. Nair, and J.K. Tien, Center for StrategiC MaterIals, HKSM, Columbia Univ., New York, NY 10027 In thIS study, the kInetICS and mechanIsms of deformation during HIP consolIdation were examIned at HIP conditions of lower pressures and temperatures than normally reported for nickel-base superalloys. The goal was to promote slower deformation mechanisms such as power law creep and superplastic flow. Two series of HIP runs of three different ini tial powder size distributions (monosized, bimodal, and fullsize distributions) were conducted at HIP conditions of 1000 C at 10.3 MP~ and 900 C
at 103 MPa for hold times ranging from 5 minutes to 1 ~o minutes. Kinetics of densification will be reported and discussed wi th respect to prior hia:her temperature and pressure data. The
~~i~~~~ti~~og~ ~ri ~~~tr~1~;: e~~~~rs~~~iaCi~~darge~~~et~i~~O~~~~ prior
particle
boundaries
(PPS)
in
the
fully
consolidated
material with a resultant rise in mechanical properties. "This
work
was sponsored by the Air Force under contract AFOSR-
82-0352, monitored Caplan.
by
Dr.
Alan
TMS Annual Meeting 11 homogeneity and reduced scatter of properties. The interactions of prior structure, homogenization practise, aging temperature, and aging t:ime have been studied to develop a basis for a microstructural test that can lead to a new criterion for homogeneity in billet material. The new test utilizes the dependence of the precipitation of the OCT Y" upon the distribution of niobium.
H. Rosenstein and Dr. Ivan F.
(11 :40 a.m.) (10:00 a.m.) POROSITY IN SUPERALLOY SINGLE CRYSTALS PROCESSED UNDER HIGH THERMAL GRADIENTS: D. D. Pearson, D. L. Anton, A. F. Giamei, United Technologies Research Center, East Hartford, CT 06108 Single, [OOn-oriented crystals of a nickel based superalloy were processed in a laboratory high-gradient furnace. The furnace employs a graphite resistance heated element, a radiation baffle, and a watercooled radiation trap below the baffle. Crystals were grown in vacuum and under argon at atmospheric pressure. The element is constructed with a variable cross section that is tapered just above the baffle to maximize heat input and the thermal gradient at the liquidus of the alloy. A maximum melt temperature of 1600°C was used. A thermal gradient of 130°C/cm was recorded at 1370°C just above the liquidus of the alloy. Crystal bars 14.4 mm in diameter were grown in alumina/silica shell molds similar to those used for producing gas turbine hardware. Each crystal was started from a 1.6 mm pencil seed at a rate of 76 mm/hr and slowly accelerated to rates up to 200 mm/hr under computer control. Volume percent porosity and average pore size were measured as functions of distance In representative bars. The effect of various solidification parameters on porosity and its influence on LCF behav'ior will be discussed.
(10:25 a.m.) THE INFLUENCE OF MICROSTRUCTURE ON HYDROGEN ENVIRONMENT EMBRITTLEMENT AND FATIGUE RESPONSE OF A SINGLE CRYSTAL NICKEL BASE SUPERALLOY, Leslie G. Fritzemeier, Rocketdyne Division, Rockwell International, 6633 Canoga Avenue, AC29, Canoga Park, CA 91307 Turbine blade materials are utilized in liquid 02/H2 fueled rocket engine turbopump turbines such as the space shuttle main engines under significantly different conditions than those for which they were developed. High mean stress high cycle fatigue, extreme thermal fatigue and Hydrogen Envi ronment Embrittl ement (HEE) resistance are of primary concern. Consequently, microstructural optimization to provide improved fatigue and HEE resistance in candidate SSME single crystal nickel base superalloys has been undertaken. Varied gamma prime sizes and morphologies, including duplex and rafted structures, have been produced through heat treatment adjustments and stress coarsening and have been evaluated through high pressure hydrogen tensile testing and cyclic loading. Both fatigue and HEE response are influenced by the degree of slip dispersal afforded by the strengthening microstructure. Fractographic and TEM analysis of slip character will be presented.
(10: 50 a.m.) ON THE STABILITY OF STRESS-ANNEALED y-y' STRUCTURES: M. V. Nathal, and R. A. MacKay, NASA Lewis Research Center,-----"CIeVeTand, OH 44135. In nickel-base superalloys subjected to an applied stress at elevated temperatures, the initially cuboidal or spherical y' particles coalesce into lamellae ("rafts") perpendicular to a tensile stress and parallel to a compressive stress. Although this directional coarsening can proceed at very rapid rates, the lamellar structure becomes quite stable once it is formed, and only sl ight thickening of the lamellae is observed after prolonged creep exposure. This lamellar thickening appears to be significant, as it has been linked to the onset of tertiary creep in some alloys. The purpose of this study is to investigate the 1 imits of stabil ity of such 1 amell ar structulies. Three single crystal alloys were stress-annealed at 1000 C to form the y-y' 1 amell ae, and were subsequently gi yen vari ous thermal exposures. The infl uence of alloy composition on raft stability will be discussed.
(11 :15 a.m.) A MICROSTRUCTURAL 'fEST FOR CHEMICAL HOMOGENEITY IN INCONEL 718 BILlET: J. F. Radavich, Materials Engineering Dept., Purdue Univ. W. Lafayette, IN. 47907,W. Couts, R&D. Dept., Wyman-Gordon Co., N. Grafton, MA. 01536, J. A. Corrado, Materials Engineering General Electric Co., Cincinnati, O. 45215
H.
In the past, Inconel 718 has been judged "homogeneous" if the Laves phase vas not present. New specifications for forged Inconel 718 :impose stricter limits upon strength and grain size uniformity. It is believed that a greater degree of chemical homogeneity in the billet will result in :improved microstructural
mE INFLUENCE OF (]!ROMIUM OONTENT a; mE FATIGUE IlIACI PROPAGATION IN 718 AlLOYS KI 810· I: I. -!. Chan., Me tall urgy Laboratory. Corporate Research and Development. General Electric Company, Schenectady, NY 12301 A series of 718 alloy compositions with a systematic variation of chromium content hal beon prepared to explore the role that chromium. plays in providing oxidation resistance in super.lloya. FCP behavior has boen evaluated at 810 0 K in air using different frequencies, 'waveforms. and R-ratios. At. slow frequency, a low chromiUIII content resulted in an accelerated crack srowth rate. while a hiSh chromium content showed 8 negligible frequency dependence. Fractoaraphy revealed a consistent correlation between the transition frOli transgranular to interIranular fracture and the acceleration of crack growth rate. The relul ts sUllest that the mechanism of time-dependent FCP in 718 alloys at 810 0 ( is simply enviro_entally assisted crack Irowth. akin to stress corrosion cracking, and that the high chromium addition can effectively suppress the frequency dependonco of FCP.
HYDROMET ALLURGICAL REACTOR DESIGN & KINETICS - I Sponsored by TMS-AIME Hydrometaflurgy, Physical Chemistry, and Electrolytic Processes, and SME-AIME Chemical Processing Committees Monday, March 3,1986 La Galerie 6 Marriott Hotel 8:30 a.m. Session Chairpersons: Renato G. Bautista, Chemical and Metallurgical Engineering Department, Mackay School of Mines, University of Nevada Reno, Reno, Nevada 89557; G. P. Demopoulos, Metallurgical Engineering Department, McGill University, Montreal, Quebec H3A 2A7, Canada
(8:30 a.m.) KINETICS OF FERRIC CHLORIDE LEACHING OF SILVER, ANTIMONIAN SILVER AND SILVER CHLORIDE: J. E. Dutrizac, CANMET, 555 Booth Street, Ottawa, Canada KIA OGle The kinetics of dissolution of disks of pure Silver, 5% Sb-silver and silver chloride have been determined in FeC1 -NaCl-HCl media 3 over the temperature range 25-95°C. Silver and antimonian silver are rapidly attacked by ferric chloride with the formation of Agel which accumula tes on the surface of the metal. The ra te is controlled by the outward diffusion of the Agel reaction product through the liquid boundary layer into the bulk solution, and the rate is a function of the disk rotation speed. Also, the leaching rate increases with increasing temperature and total chloride concentration which enhance the solubility of Agel; the rate decreases wi th increas ing Agel concen tra tions, which lower the AgCl diffusion gradient. As expected, the dissolution of AgCl is virtually identical to that of metallic silver or the 5% Sbsilver alloy, and linear kinetics are observed for all three systems.
(9:00 a.m.)
LEACHING OF ILMENITE BY HYDROCHLORIC ACID: R. J. Orth and K. C. Liddell, Department of Chemical Engineering, Washington Sta~ University, Pullman, WA 99164-2710. Studies on the dissolution of ilmenite (FeTi0 3 ) were conducted at hydrochloric acid concentrations of 3, 4, 5 and 6 M, and at temperatures of 58, 67, 72, 87, and 95°C. Both titanium and iron dissolution rates showed approximately a hdlf-order dependence on hydrogen ion activity. Values for the apparent activation energies of iron and titanium were found to be 66.0 kJ/mol and 54.3 kJ/mol respectively. In addition, a small increase in the dissolution rates of both titanium and iron was observed when varying concentrations of sodium chloride were added to 3 M hydrochloric acid. This was apparently due to the increase in hydrogen ion activity upon addition of sodium chloride. A partial equilibrium model was then developed by combi ni ng the experimentally determi ned di sso 1 uti on rate expressions for titanium and iron with calculated thermodynamic equilibrium constants for the various species in solution.
12TMSAnnuai Meeting (3:30 a.m.)
MATHEMATICAL MODEL rOR THE LEACHING KINETICS OF ZINC OXIDE IN ACID SOLUTIONS: N. Ranjan, F.M. Doyle-Garner, University of California, Berkeley, E. Peters, University of British Columbia A mathematical model is developed to describe the leaching kin-
etics of zinc oxide in dilute acids. The model assumes that the leaching rate is controlled by mass transport, and considers the contributions of diffusion, convection and electrical migration to mass transport. Diffusion and convection are combined into a single mass transfer coefficient, using Sherwood's semi theoretical correlation. The model is simplified by assuming steady state conditions, a uniform electric field in the boundary layer and charge neutrality. The boundary conditions used to solve the flux equations are the bulk concentrations of the individual species, obtained by assuming thermodynamic equilibrium, the surface concentrations, derived by assuming that the dissolution reaction is at chemical equilibrium, and the stoichianetric tionship between the fluxes of individual species. The . cle radius, and hence the fraction reacted, is then found function of time fran the fluxes. The leaching rates cted by this model are compared wi th experimental rates. -nZ',j{
(10:30 a.m.) MODELLING THE RATE OF LEACHING OF CHALCOPYRITE BY FERRIC
facilities at the Ashio Smelter in 1956. Since then, many moditications and developments have been done in the flash smelting furnace and other fac il it i es. Those techn i ques were app 1 i ed in the 1arger scale smelting plant which was installed in 1962. This flash smelting plant was the origination of the "Furukawa Type Flash Smelting Process" which has been adapted by several smelters in and outside Japan. All of these smelting plants (total of eight furnaces) have been successfully operated. BaSically, the energy consumption in the flash smelting furnace is smaller than that in the reverberatory furnace. For further reduction of fossil energy consumption at the Ashio smelter, a 2600 Nm'/h oxygen plant was installed in 1978 and expanded up to 3000 Nm'/h in 1979. Product of the oxygen plant has been utilized both in the flash smelting furnace at the rate of 2650 Nm'/h and in the converter furnace. The oxygen enri ched prQcP« "i r of the fl ash smelt i ng furnace since 1978 to 1983 averaged 40 %, and that of the converter furnace (only during slag blow) averaged 23 % respectively. !.doption of the oxygen enrichment process ~as brought us a lot of "'-ofit such as energy saving, increase if. I,roduction capacity and further elimination of environmental problems . F<.ecently, the shortage of imported copper concentrates has fo~ced ;s to operate at copper production rate of 80 % of full capacl ty. The lower feed ra te of the fl ash sme lt i ng furnace has 1ed us to the commercially pure oxygen flash smelting operation for a long time since May, 1984. This paper introduces several modifications on the smelting facil ities for the cornnercially pure oxygen flash smelting operation, countermeasures with SO, in the waste gas, and the elimination of impurities such as As, Sb and Bi in the flash smelting furnace.
CHLORIlJt. Ot{ CUPRIC ChLORIlJE: H. L. O'Malley, K. c. Liddell, Department of Chemical Engineering, Washington State University,
Pullman, WA
99164-2710.
(8: 55 a.m.) Particulate chalcopyrite was
leached in a solution containing varying amounts of He!, NaC!, and oxidant, FeCI or CuGl? The concentration range studied was from O.05M ~o 3.0M for 50th oxidants. The Hel concentration was varied between
O.4tt and 4.5M, and the NaCl concentration from 0.0 to 4.5M.
The
initial solid/oxidant molar ratio in each batch leach was chosen
to produce measureable changes in the copper and iron solution component concentrations. Rate laws were generated for both FeCI and Cuel leaching. Effects of surface area, temperature, hydrogen ion, choloride and oxidant concentrations are discussed for both lixiviants.
(11:00 a.m.) T.L. LEACHING PROCESS: A PHENOMENOLOGICAL MODEL FOR OXIDE COPPER ORES TREATMENT: J. R. Rauld, R. Montealegre, P. A. Schmidt and E. M. Domic, Sociedad Minera Pudahuel Ltda. y Cia. C.P.A., Av. Lyon 527, Santiago - 9 - CHILE This paper provides a theoretical explanation of the unique characteristics of the T.L. process by means of a phenomenological model. As T.L. is a nonconventional leaching process, its hydrodynamic properties are also very distinctive. The first model's target is to describe T.L. leaching fluid-flow pattern through the ore-bed particles by using the conservation equations. The validi ty of the assumptions made is demons tra ted by a series of chemical tracer tests. Next, a kinetic description of the main leaching reactions is given by using a topochemical approach that matches with experimental results. A practical example on the application of the model to a real are is given. The model predicts the effect of the independent variables on the main system responses: me tal recovery and acid consump tion. By us ing some other experimentally determined parameters, the model permits to obtain the optimum economical operating conditions for applying T.L. leaching to a new are.
INNOV A nONS AND PRODUCTIVITY INCREASE IN NO~-FERROUS PYROMET ALLURGICAL PLANTS I Sponsored by the TMS Pyrometallurgical Committee Monday, March 3, 2986 La Galerie 2 Marriott Hotel 8:30 a.m. Session Chairmen: C. Landolt, Superintendent of Process Technology, Copper Cliff Smelter lnco Ltd, Copper Cliff, Ontaria, Canada; Juho Makinen, Plant Metallurgist, Outokumpu Oy, Harjavalta Smelter, 29200 Harjavalta, Finland
(8:30 a.m.)
. LASH SMELTING WITH COMMERCIAL! Y PURE OXYGEN AT ASHIO SMELTER 0samu fUJii, General Manager, and \ asushi Watanabe, Meta 11 urgi st, Ashi 0 Smelter, Furukawa Company, Ltd., Japan Furukawa Company introduced the Flash Smelting Process from Outokumpu Oy of Finland in 1954, and installed the flash smelting
CURRENT INNOVATIONS AT CALETONES SMELTER: R.Espinosa, B.Hornicki,C.Queirolo,El Teniente Division - Code leo Chile Supported on its own technological developments, E1 Teniente Division is presently running a modernization program for the Caletones Smelter to increase capacity, lower operating costs and improve working conditions. The main current projects include the modification of the converter aisle, the substitution of the present Teniente Modified Converters by larger units and a new gas handling system. The converter aisle modification considered ralslng 5.5 meters the crane rails and roof and substi tution of nearly 60~ of the building to permit the installation of new Teniente Modified Converters and gas handling system. The new Teniente Modified Converters (5 m ~ x 21 mL) to be installed during 1987 will increase 30% of the concentrate smelting capacity and lower 34~ the specific fuel consumption, besides other benefits. The converter aisle modification and the process performance projected for the Caletones Smelter are presented in this paper.
(9:20 a.m.)
RECENT INNOVATIONS AT THE HUELVA SMELTER: D. de la Villa, Metallurgical Manager, F. Cevallos, Maintenance Superintendent, P. Barrios, Superintendent of Metallurgical Department, Rio Tinto Minera, Huelva, Spain. Since 1975 Rio Tinto Minera is operating with an Outokumpu designed flash furnace. An env i ronmenta 1 comp 1 i ance programme was developed to renew and improve the existing process gas collecting and handling systems for the converters and anodes furnaces, by install ing new evaporative spray cool ing systems. Reduction of the secondary emissions was achieved by computerised converter movements and the design of a new system to feed the scraps while the converter is at the blowing position. Due to the increasing cost of energy, in 1981 oxygen enriched operation was adopted, by using 2000 Nm'/h pure oxygen. During late 1984 a 300 tonnes per day oxygen plant was erected by SEO which supp 1 i es oxygen to RTM over the fence. Thi s supp ly permits an oxygen enrichment of air of 35 - 40 %. A restructuring plan was started, planning and programming procedures were adopted to achieve a higher productivity with lower operational costs. Recent innovations including the shortening of the furnace reaction shaft, installation of a central jet type concentrate burner, waste gas boiler recirculation and various energy savings, are also described.
(9:45 a.m.)
RECENT IMPROVEMENT OF FSFE OPERATION AT TAMANO SMELTER: Takaaki Shibata, Deputy General Manager, Tsuneo Maruyama, Assistant Superintendent, and Mitsura Uekawa, Assistant Superintendent, Hibi Kyodo Smelting Company, Ltd., Japan Tamano Smelter started operation in 1972 adopting FSFE (Flash Smelting Furnace with Furnace Electrodes) process with an initial product i on capac i ty of 84, 000 MTPY of new anode.
TMSAnnual Meeting 13 At present, Tamano has increased its annual production capacity to 168,000 MT which is twice the initial capacity. In the process of expansion, FSFE in the Tamano Smelter has conducted severa 1 measures to improve the opera ti on effi c i ency of the furnace, to increase the productivity and to lesson the energy consumption and cost. To mention some, these measures are oxygen enrichment of air blown into furnace, fuel conversion to coke, etc. and modifying the water cooled up-take to make it a boiler. Further, Tamano FSFE has recently achieved a great success in decreasing copper loss in the slag and also decreasing electric power consumption of furnace electrodes by controll ing the Co concentration in the FSFE when charging the powder coke. The recent improvement of FSFE operation in the Tamano Smelter is outlined in this paper.
(10:20 a.m.) PRODUCTI VITY INCREASE AND PLANT OPTIMI ZATION: EXAMPLES FOR DETERMINATION OF BASIC CRITERIA: Dr. Gunter Fleischer, Kabe1meta1, Prof. Dr. Ing Dr.h.c. Roland Kamme1, Institut fUr Metallurgie-Metallhuttenkunde - Technische Universitat Berlin, Dip1 .-Ing Uwe Lembke, Berliner Kupferraffinerie GmbH The development of a model that describes the efficient recovery of valuable metals from the operation of multi-stage metallurgical processes is presented. An example is gi ven for us i ng th is model for the pyrometallurgica1 recovery of tin, lead, zinc, nickel and silver from the operation of a secondary copper plant which uses copper scrap and copper containing waste materials. The model uses a mass balance analysis to calculate the distribution and output of the process cons t i tuents for each process stage and to determine the reclamation efficiency of each stage. The model can also be used to make decisions for the optimum plant operation. The util ity of this model for a converter and blast furnace process is shown.
(10:45 a.m.) TODAY'S OPERATION OF THE ONAHAMA SMELTER: Hiroshi Kono, Manager of Operations, Yukio Miyamoto, Superintendent of Smelter, Haruhiko Asao, Superintendent of Research and Development, Toshihiko Igarashi, Assistant Superintendent of Research and Development, and Michio Nishiwaki, Senior Metallurgist of Smelter, Onahama Smelting and Refining Company, Ltd, Onahama, Japan The Onahama Smelting and Refining Co., Ltd., which depends on oversea supplies for a major part of its copper concentrates, has been forced to reduce its production volume due to the world-wide trend towards reduci ng concentrate supplies. Under these conditions, the Onahama Smelter has changed the operating procedures for (1) cost reduction, especially for the converters and acid plant operations, (2) utilization of newly developed energy conversation innovations. This paper presents the current operation of the Onahama Smelter.
years without major alterations to the basic process or existing eqUipment. A brief description is given of the measures taken during the first five of the past six years to improve the continuity of the sinter plant operation. The emphasis of the paper, however, is wi th the approaches used during the last year including maintenance p/m and planning strategies, personnel and manning changes, and specific operational and equipment modifications made to improve productivity.
ORDERED PHASES TMS-AIME General Abstract Session Monday, MArch 3, 1986 8:30a.m. Session Chairman: Jeff Perkins, Materials Science Naval Postgraduate School, Monterey. CA 93943
(8:30 a.m.) ELEVATED TEMPERATURE DEFORMATION MECHANISMS IN CoAl: D.L. Yaney,
and W.O. Nix, Dept. of Materials Science and Engineering, Stanford University, Stanford, CA 94305 and A.R. Pelton, Dept. of Metallurgy and Ceramics, Ames Laboratory, Ames, Iowa 50011. The mechanisms controlling elevated temperature deformation in CoAl were investigated. Transmission electron microscopy was used to identify the slip systems operating during extrusion of po1ycrystalline Co-49.3 at.%A1 at 1505 K.
{llO),
<001>{100} as well as {lIO} slip was observed indicating that sufficient slip systems exist in CoAl to allow for general plasticity in the absence of diffusional mechanisms. Additional information regardine the elevated temperature deformation behavior of near-stoichiometric CoAl was obtained from strain rate change tests. High speed data acquisition techniques were used to collect data immediately following a strain rate change, thus allowing detailed information concerning the deformation transients to be obtained.
(8:50 a.m.) DISTRIBUTION OF BORON AND OTHER SOLUTES IN POLY CRYSTALLINE Ni3Al :
S.S. Brenner, H.C. Burke and D.O. Sieloff, Department of Metallurgical and Materials Engineering, University of Pittsburgh, Pittsburgh, PA
15261.
The ductility and high-temperature strength of polycrystalline Ni3Al can be markedly changed by additions of boron and such alloying additions as hafnium and iron. Initial results of an atom-probe study to determine the distribution and state of aggregation of boron and various solutes in the matrix and at grain-boundaries in Ni3Al of different compositions are described. The lattice-site occupation probabilities of the solutes in the ordered intermetallic have been determined by observing the sequence of field evaporat ion of atoms from the {OOI} superlattice planes.
(11 :10 a.m.) EXPANSION OF SOFTENING CAPACITY FOR LEAD BULLION: J. V. Haop, P. G. Wiltshire, and G. T. Leske, Broken Hill Associated Smelters (BHAS), 8roken Hill, Austral ia. Expected changes in feed ma teri a 1 s to the Port Pi ri e works of the Broken Hill Associated Smelters Pty. Ltd would have exceeded capacity of the existing continuous softening/ antimonial alloy circuit. A variety of options for plant upgrading were considered: retaining existing technology and replacing furnaces with larger units; conversion from continuous cocurrent to countercurrent softening; installation of conventional batch Harries techo10gy; batch dry drossing with caustic soda; and a novel continuous Harris process. Measurement campaigns and modell ing studies on existing plant were used to project the performance of co- and counter-current softening units, and assess the impact on the antimonial alloy operations. Kinetics and chemical studies on Harris technology were used to develop specifications for standard or dry drossing techniques to remove arsenic selectively from Bullion. A novel continuous Harris concept was developed to pilot scale and is the subject of a detailed engineering study as the preferred option.
(11 :35 a.m.) INNOVATIVE AND CONVENTIONAL APPROACHES USED TO IMPROVE PRODUCTIVITY AT THE ASARCO EL PASO LEAD SMELTER: Smelter
Staff, Asarco, El Paso
(9: 10 a.m.) SITE OCCUPANCY OF TERNARY ADDITIONS TO Ni3Al BY AXIAL ELECTRON CHANNELING MlCROANALYSIS.· J. Bentley, Metals and Ceramics
Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 Lattice site location of ternary additions to L12 ordered N13Al is of interest for alloy development. Although no lattice planes contain only Al atoms, certain zone axes (including <001> and
(9:30 a.m.) EFFECT OF BORON AND ALUMINUM CCNTENT ON SURFACE SEGREGATION IN Ni 3 Al:' C. L. White, C. T. Liu and R. A. Padgett, Metals and
Ceramics DiviSion, oak Ridge National Laboratory, Oak Ridge, TN
By the application of many simultaneous approaches, the
37831
AsarcQ El Paso Lead Smelter has been able to significantly improve the productivity of the plant over the past six
The propensity for intergranular failure in the. intermetallic compound Ni3AI is strongly influenced by small boron additions
14 TMS Annual Meeting 500 wt ppm) and small variations (. . . . 1 at. %) in aluminum content. studies indicate that the beneficial effects of boron in • % Al result from its tendency to segregate to grain es but not to free surfaces. This unusual segregation is in qualitative agreement with Rice I 5 classical thermotreatment of rapid grain boundary separation. Comparison segregation with grain boundary segregation will be Ni3A1 alloys without boron; and to boron doped alloys 25 at. % Al, where the boron is not very beneficial. It'rellmlnary results indicate that boron does not have a strong to segregate to free surfaces of the alloys with IOOre at. % Al. *Research sponsored by the Division of Materials Sciences, Department of Energy under Contract No. DE-ACOs-840R21400 th Martin Marietta Energy Systems, Inc.
environment, with much lower ductilities observed in air than in vacuum. The loss in ductility is accompanied by a change in fracture mode from transgranular to intergranular. The severity of this environmental effect on elevated temperature ductility was found to be affected by preoxidation in air as well as by the aluminum content of the aluminide. The embrittlement due to oxygen becomes less severe with a decrease in aluminum concentration from 24 to 21 at. %. All the results strongly suggest that the aluminide alloys tested in oxidizing environments are embrittled by a dynamic effect involving decohesion of atomic bonds across grain boundaries as a result of oxygen adsorption/absorption at the crack tip. *Research sponsored by the Division of Materials Sciences, U.S. Department of Energy, under contract DE-ACOs-840R21400 with Martin Marietta Energy Systems, Inc.
(11: 10 a.m.)
9:50 a.m.) HE EFFECT OF COOLING RATE ON THE FRACTURE MORPHOLOGY AND
STRUCTURAL STUDIES OF MODIFIED IRON ALUMINIDES: H. P. Longworth
*
NTERGRANULAR SEGREGATION OF BORON IN Ni 3Al: Ashok Choudhury, t R. Brooks t , and C. L. White, Metals and Ceramics Division, Ridge National Laboratory, Oak Ridge, TN 37831 is known that microalloying the L12 ordered intermetallic compound Ni 3Al with boron reduces its susceptibility to intergranular fracture. The fracture morphology of boron doped (500 ppm) Ni3Al of substoichiometric composition (24 at.% AI) is found to be rather sensitive to the cooling rate subsequent to high temperature annealing. Preliminary results indicate that higher cooling rates promote intergranular fracture. The level of boron segregated to the grain boundaries exposed by tensile fracture will be studied by Auger Electron Spectroscopy. Attention is also focussed on the reversibility of such intergranular segregation. The technical significance of such information is discussed. *Research sponsored by the Division of Materials Sciences, U. S. Department of Energy under Contract No. DE-ACOs-840R2l400 with Martin Marietta Energy Systems, Inc. tThe University of Tennessee, Materials Science and Engineering, Knoxville, TN 37996.
and D. E. Mikkola, Department of Metallurgical Engineering, Michigan Technological University, Houghton, MI 49931. Transmission electron microscopy has been used to examine the microstructural changes effected by additions of Mo and Ti to various iron aluminides near Fe3Al. As-cast structures range from lamellar-type mixtures of the disordered and D03 phases to single phase 003 depending on alloy additions and aluminum content. A variety of phase transformation mechanisms are involved in developing the microstructures with the kinetics of the transformations and the APB types and morphologies dependent on chemical composition. An important observation is the change in the 003 phase slip vector from <111> to <110> on alloying.
(11 :30 a.m.) EFFECTS OF Mo AND Ti ADDITIONS ON THE OO3+B2 TRANSITION TEMPER-
ATURE FOR IRON ALUMINIDES NEAR Fe3Al: R. T. Fortnum and D. E. Mikkola, Department of Metallurgical Engineering, Michigan Technological University, Houghton, MI 49931.
(10: 10 a.m.) HOT DUCTILITY AND MICROSTRUCTURAL CHARACTERISTICS OF DUCTILE NICKEL ALUMINIDES:' M. C. Maguire, G. R. Edwards, Colorado School of Mines, Dept. of Metallurgical Engineering, Golden, CO 80401, M. L. Santella and S. A. David, Oak Ridge National Laboratory, P.O. Box X, Oak Ridge, TN 37831 Boron doped Ni3Al and Ni 3Al-type alloys in the polycrystalline form have been shown to have room temperature ductilities exceeding 50%. However their hot ductility has been found to be poor leading to problems associated with hot workability and welding. One alloy, designated IC-50, was investigated to determine factors controlling the hot ductility. IC-50 specimens contained by atomic percent: 23.5 Al-O.s Hf-O.l B, bal Ni. This alloy was produced by two different techniques: (1) arc melt, cast and cold-worked into sheet, and (2) hot extrusion of canned powder compact. The paper will describe the differences in hot ductility and microstructural characteristics of the materials produced by these two methods. *Research sponsored by the U.S Department of Energy under DOE/FE AA 15 10 00 0, Advanced Research and Technology Development ~~:~!~t EC§M~l.~terials Program, Work Breakdown Structure
(10:30 a.m.) AN INVESTIGATION OF GRAIN BOUNDARIES IN BORON-DOPED Ni 3Al BY ATOM PROBE AND TEM:* J. A. Horton and M. K. Miller, Metals and Ceramics DiviSion, Oak Ridge National Laboratory, Oak Ridge, TN 37831.
Boron additions to Ni3Al improve the mechanical properties by preventing the inherently weak grain boundaries from failing. The atom probe field ion microscope is well suited to characteri ze the st ructu re and chemi s try of unembri ttl ed bounda ri es since the technique does not require the boundaries to be exposed by a fracture process. Specimens of Ni-24 Al-0.2 at. % B were prepared from normally cast and from rapidly sol idified material. The boron had a similar beneficial effect on the rapidly solidified material. Results from an atom probe and TEM characterization of the boron distribution will be presented. *Resea rch sponsored by the Di vi s i on of Materi a 1s Sci ences, U. S. Department of Energy, under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.
(10:50 a.m.) DYNAMIC EMBRITTLEMENT OF BORON-DOPED Ni3Al ALLOYS AT 600°C: c. T. Liu and C. L. White, Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
*
Boron-doped Ni3Al alloys, with and without 0.5 at. % Hf, were tensile tested in vacuum and in oxidizing environments at 600°C. Tensile ductility was found to be a strong function of test
The 003-+82 transition occurs at 540°C in Fe3Al. This transition temperature can be increased by at least 250°C by various alloying additions, thereby making it possible to exploit the desirable high temperature properties of the D03 phase. The effects of Mo and Ti additions on the transition temperature have been determined wi th x-ray diffraction and site occupancies have been inferred from diffracted intensities. The results have been related to 650°C stress-rupture tests on the alloys.
PHYSICAL CHEMISTRY I: REDUCTION PROCESSES Sponsored by the TMS Physical Chemistry Committee and the ISS/PTD Monday, March 3, 1986 Mardi Gras N Marriott Hotel 8:30a.m. Session Chairmen: J. P. Hager, Colorado School of Mines, Dept. of Metallurgical Engineering, Golden, CO 80401; S. E. Khalafalla, U. S. Bureau of Mines, Twin Cities Research Center, 5629 Minnehaha Ave. South, Twin Cities, MN 55417
(8:30 a.m.) THERMOCHEMICAL MODELING OF DIRECT REDUCTION IRONMAKING; D.V. Vlachossotiros. M. Moinpour, and Y.K. Rao, Department of Materials Science and Engineering, University of Washington. Seattle, WA. The direct reduction ironmaking process lof the Midrex variety J was modeled utilizing the method of staged-equilibrium. The transfer of oxygen from the solid oxides to the reducing gas-phase was effected progressively in a number of stages. Each stage differed from the previous by a set temperature interval (say 1OOC J • The heat effects associated with gas cooling. solids preheating. and reaction enthalpy changes were determined for any given stage and then for the process as a whole. Reduction is assumed to occur successively, viz., Fe 0 l +Fe l 0 4 , 2 Fe 0 +FeO. and FeO+Fe with due allowance made for ciil"rboi'l 3 4 deposition. The operational results from an industrial unit were analyzed by this method and the net excess enthalpy, consistent with the attainment of equilibrium in the reducing gas-phase, was derived for the operation.
TMSAnnual Meeting 15 (9:00 a.m.) KINETICS OF REDUCTION OF FERRIC OXIDE IN SLAG BY CARBON IN IRON: K. Upadhya, Assistant Professor of Metallurgical Engineering, Department of Civil Engineering, Mechanics and Metallurgy, University of Illinois at Chicago, P.O. Box 4348, Chicago, Illinois, 60680. Measurement of the rate of reduction of ferric oxide in a dilute solution in CaO-AI203-Si02 slag by carbon was investigated using a composite crucible as a container so as to exclude graphite from the system. The experimental variables studied to elucidate the reaction mechanism(s) were pressure inside the crucible, carbon content of metal, ferric oxide concentration and slag composition. The results obtained are explained by postulating the existence of a gas film at the slag-metal interface. It is suggested that the rate controll ing step during the initial fast reduction stage lies at the gas/slag interface, and it changes to the gas/metal interface during the relatively slower second stage of reduction. It is also postulated that in the first stage of reduction, ferric oxide is reduced to FeO through an exchange reaction between ferric oxide and elemental iron, without CO evolution.
(9:30 a.m.) THE REDUCTION OF IRON OXIDE BY CO GAS FRor~ SYNTHETIC LIQUID SLAGS: G. Granzdiirffer and H. Alan Fine, Department of Metallurgical Engineering and 11aterials Science, University of Kentucky, Lexington, KY 40502-0046; D. Meyer, D. Janke and H.-J. Engell, Metallurgie Abteilung, Max-Planck-Institut fiir Eisenforschung, Dusseldorf, ,I. Germany. The rate of reduction by CO gas of iron oxide from liquid synthetic CaO-MgO-Si02-FexO slags rich in iron oxide and similar to those which may be found in direct smelting and conventional iron and steelmaking processes is studied. The slags are contained in iron or MgO crucibles and the rate of reaction detemined from measurements of the rate of evolution of C02 using an infrared gas ana lyzer. The influence of CO partial pressure, temperature, slag basisicity, sulfur content of the slag and crucible material is examined. Empirical rate equations are developed and the ratecontrolling mechanisms are discussed.
ating variables. With rising temperature, the chlorination of the same mineral necessitated the use of ever-larger quantities of carbon in the charge. The energy consumption of the chlorination process was at first determined employing ordinary material and energy balances. By using the more restrictive stagedequilibrium approach, the net excess (deficit I enthalpy requirement of the process was evaluated. The potential benefits of the present kind of analyses to the industrial manufacturers of TiCI are critically examined. 4
(11 :30 a.m.) SOLUBILITY OF NITROGEN IN POTASSIUM-CARBON-OXYGEN-NITROGEN MELTS: M. Alam and T. DebRoy. Department of Materials Science and Engineering, Metallurgy Program, The Pennsylvania State University, University Park, PA 16802. The reaction between molten KeN contained in graphite crucibles and CO/N 2 gas mixtures waS studied to understand the reaction behaviour of KeN in the blast furnace. It was found that KCNU) absorbed oxygen from the gas phase and a melt containing K, C, N and 0 was formed which on cooling resulted in the formation of KeN, KoeN and K C0 , KCN(i!..) was reacted with various CO/N Z 3 Z mixtures and the nitrogen content of the melt was determined as a function of reaction time. The variables studied were partial pressures of CO and N and temperature.
Z
PLASMAS FOR METALLURGICAL APPLICATIONS I: Plasma Modelling and Plasma-Materials Interactions Sponsored by the TMS Physical Chemistry Committee Monday, March 3, 1986 La Galerie 1 8:30 a.m. Marriott Hotel Session Chairmen: K. J. Reid, Mineral Resources Research Center, 56 East River Road, Minneapolis, MN 55455; I. D. Sommerville, Dept. of Metallurgy and Materials Science, University of Toronto, Toronto, Ontario, M5S lA4, Canada
(10:00 a.m.)
CATALYSIS OF BOUDOUARD REACTION: A.A. Adjorlolo and Y. K. Rao, FB-l0, University of Washington, Seattle, WA The kinetics and mechanism of alkali-carbonate-catalyzed Boudouard (C-CO ) reaction were investigated in the range o BOBoC to 96S C. The catalysts studied included Li7CO~, Cs 2 C0 , 3 K C0 and Na CO. Ultra high purity graphite pelletS" confain3 2 2 ing 1 mol% cation 6f the alkali carbonate were reacted with CO 2 bearing gases under isothermal conditions and the reaction rates were monitored on a thermogravimetric unit. The influence of gas composition on the rate of Li 7 C0 -catalyzed reaction was ex3 amined in detail. It appears thar the CO -partial pressure has 2 negligible effect on the reaction rate whereas CO tends to inhibit the reaction. The rate-inhibition by CO is especially marked at lower temperatures. A catalysis mechanism involving alkali graphitic-oxide (AGO) surface complexes as active intermediates has been proposed and a rate equation deduced therefrom gives a satisfactory representation of the measured rate data for the Li C0 -catalyzed reaction. 2 3
(10:30 a.m.) KINETICS OF CARBOTHERMIC REDUCTION OF ALUMINA, l800-2000 0 C: R. A. Frank, C. W. Finn and J. F. Elliott, Dept. of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 The physico-chemical path by which it may be possible to carry out the carbothermic reduction of alumina at temperatures between 1800 and 2000 0 C has been investigated. The smelting reaction of alumina with carbon to form CO and aluminum dissolved in a solvent metal can be carried out in the desired temperature range as a result of a lowered activity of aluminum and evolution of CO at pressures in the range of 0.1 atm. abs. The kinetics of the reaction and the influence of tin and copper as solvent metals are reported. Methods for separating aluminum from these solvent metals by solidification processing have also been studied, and are reported.
(11 :00 a.m.)
CHLORINATION OF TITANIA: B.K. Chadwick and Y.K. Rao. FB-l0. University of Washington, Seattle, Washington The chemistry of the chlorination process is examined in detail and equilibrium gas compositions were computed for several different· operational conditions. The Icarbon requirement' of the chlorination per se was found for each set of oper-
(8:30 a.m.) PLASMACHROME PROCESS FOR FERROCHROME PRODUCTION: THERMOCHEMICAL MODELLING AND APPLICATION TO PILOT PLANT DATA: N. S. Srinivasan,
Dept. Theoretical Met., Royal lnst. Technol., 1 o()lf~-; StockhofrTi; Sweden, S. Santen, SKF Steel Engineering AB, 183 00 Hofors, Sweden, L.-I. Staffansson, Dept. Theoretical Met., Royal lnst. Technol., 100 44 Stockholm, Sweden. In this paper, a theoretical analysis of the plasmachrome process has been conSidered. A thermochemical model has been developed for the process based on a heat and mass balance for the smelting and shaft zones of the reactor. For a gi ven set of operating condi tions, the model calculates the maximum grade of ferrochrome that can be produced. The model has been applied to pilot plant data on ferrochrome/charge chrome production. In general, model predictions are in reasonably good agreement wi th observed data. The plasmachrome process has the flexi bili ty to accept different types of raw material addi tions. The model has been used to evaluate the effect of such changes in practice. The paper discusses these aspects and the physical chemistry of the process. Impact assessments of raw material qual i ty, alloy grade and operating cond1 tions on process performance are also presented.
(9:00 a.m.) MODELING OF COBALTITE REDUCTION IN A THERMAL PLASMA:
L. S. Richardson, D. J. Varacalle, Jr., R. L. Miller, Idaho National Eng. Lab., EG&G Idaho, Inc., P.O. Box 1625, Idaho Falls, ID
83415
As part of a program to evaluat.e the uses of thermal plasmas in materials processing, the feasibility of reducing a domestiC cobalt ore to metal was examined. The spatial distribution of temperature. veloci ty, and speci es con centra ti ons in the plume of an inductively coupled plasma (Iep) torch were estimated, using a variety of computer codes, for the addition of cobaltite to an argon plasma. Plasma condi tions were predicted wi th three different computer codes while another code was used to predict thermochemistry. Comparison with experimental measurements will be shown. Parametric studies were made for carbon-oxygen and carbon-water systems and compared wi th known resul ts. The methodology of these studies then was used to examine the cobalt-arsenic-sulfur system. Separation of cobalt as liquid from both arsenic and sulfur as gases appears to be feasi ble. lni tial experiments on cobal t oxide confirm the trend of predicted results, with some significant deviations.
6 TMS Annual Meeting -:.r:.)
PARTICLE RESIDENCE TIME DISTRIBUTIONS IN A NON-TRANSFERED ARC PLASMA TORCH: K. A. Prisbrey, P. R. Taylor, University of Idaho, Moscow, ID 83843.
High temperature plasma reactors offer a1 ternati ve methods for the treatment of cert::1.in mineral concentrates. The particles may be introduced into the plasma by a variety of methods, but the configurations all generate a distri bution of particle residence times. One method of characterizing these RIDs is to inject particles that undergo a certain amount of surface melting that may be characterized by digitized shape analysis.
The amount of surface modification is then related to the timetemperature distri bution of the particle. Resul ts usi ng a garnet sand in a Plasma Energy Corporation Torch system are presented.
10: 15 a.m.) APPLICATION OF A RADIALLY COALESCED PLASMA TO EXTRACTION
METALLURGY: M. C. L. Patterson, J. A. Charles, D. J. Fray, Dept. of Metallurgy and Materials Science, U. of Cambridge, Cambridge C82 3Q2, UK.
Although plasmas offer the opportuni ty for metallurgical reactions occurring rapidly at high temperatures, one of the major problems is that the residence time of the particles in the plasma is relati vely short. There have been several attempts at expanding plasmas. In this research, a 50 kW d.c. coalesced plasma formed from 12 radial electrodes is used to produce a large area of plasma. A very stable plasma is created, which totally f ills the vol urne between the electrodes. A high gas flow is passed up through the plasma, extending it and the large tail flame into a steep-sided conical region which acts as a fluidised bed container where particles may be reacted with desired residence times. The characteristics of the plasma are described and the application of this novel plasma reactor to the processing of minerals is outlined.
PRETRANSFORMA TION DEHA VIOR RELATED TO DlSPLACIVE TRANSFORMATIONS IN ALLOYS I Sponsored by the ASM-MSD Structures Committee Monday, March 3,1986 Mardi Gras I-J Marriott Hotel 8:30 a.m. Session Chairmen: W. A. Soffa, University of Pittsbugh, Pittsburgh, PA 15261; J. M. Sanchez, Columbia University, New York, NY 10027
Anderson(l984) have argued that properties of strong-coupling sU'perconductors, such as A15 compounds, imply a breakdown (If Migdal '5 theorem (the adiabatic, or Born-OppenlH-'imer approxi~ mation for separation of electrons and phonons) in these systems. The electron--phonon coupling is so strong that it must be incorporated already in zeroth order. This is the basis for 10cal phonon models. in which the electron-phonon coupling provides dn effective double well potential for a localized group of atoms. The Yu~Anderson model and an analogous local Jahn~Teller model (Abell, 1983) are reviewed in connection with displacive trans~ formations in strong-coupling alloys.
(9:30 a.m.) TWEED: THE MICROSTRUCTURE OF THE PRETRANSFORt4ATION STATE L. E. Tanner, Lawrence Livermore National Lab., Livermore, CA 94550; R. Gronsky, Lawrence Berkeley Lab., Berkeley, CA 94720; and A. R. Pelton, JIroes Lab., JIroes, IA 50011. Tweed is an interwoven, striated electron image contrast common to a wide variety of metallic (and non-metallic) cubic phases IYhich undergo displacive transformations upon cooling. This fi ne scal e, diffuse mi crostructure and associ ated diffuse diffraction streaking is due to a dense array of 11101<110> transverse lattice distortions. Tweed exhibits composition and temperature dependencies similar to those of other pretransformation effects (e.g., variations in C' = 1/2(Cll-C-12) and Ill01TA phonon anomolies, etc.), and is believed to have a primary relationship to the formation of the displacive product phase. As such, tweed is variously described as a structural short-range order, a short-range orderi ng of stra ins, s tra i n or martensitic embryos, order parameter fluctuations "dressed in strain", solitons, etc. We will describe tweed, its contrast origins, review the systems in which it appears and discuss the various models for its role in displacive transformations.
(10: 00 a. m. ) COMPUTER STUDY OF TWEED AS A PRECURSOR TO A MARTENSITIC TRANSFORMATION OF A BCC LATTICE*: P. C. Clapp, J. Rifkin, J. Kenyon, Inst. of Mat. Sci., Univ. of Conn., Storrs, CT and L. E. Tanner, LLNL, Livermore, CA. Using molecular dynamics computer simulations we have studied a BCC crystal with an interatomic potential having a second derivative which passes through zero near second neighbor distances. This causes an inherent tetragonal instability which manifests itself as random dynamic tetragonal distortions at high temperature ("dynamic tweed"), quasi-static and somewhat spatially correlated tetragonal distortions at intermediate temperatures ("static tweed") and an apparent martensitic transformation to a close-packed structure at low temperatures. The effect of simple defects (vacancies, and interstitials) on the development and spatia 1 1 oca 1 i zation of the pretransformation structure (tweed) and the subsequent martensitic transformation will also be discussed. * Supported by NSF-DMR and DOE
(8:30 a.m.) SYMMETRY ASPECTS OF PRETRANSFORMATION BEHAVIOR IN METALLIC ALLOYS J Desmond C McConnell SchlumIJerger Cambridge Research, PO Box 153 Cambridge, England A review of pretransformation behavior in metallic alloys is presented and comparisons made with simi lar phenomena in inorganic materials and minerals. Symmetry arguments are then used to develop a group-theoretical approach to pretransformation behavior in general. This treatment is particularly concerned with the analysis of short-range effects as observed, for example, in tweed textures; and space group representation theory is used to analyse both the characterist ics of short-range effects and the significance of intensity streaks. seen in diffraction mode, along high symmetry directions in k-space, as observed in premonitory transformation behavior. The symmetry principles developed are used to analyse a number of specific examples of pretransformation behavior. The general relationships between the new theory and that used in discussing incommensurate structures are discussed.
(10:30 a.m.)
BREAK
(10:40 a.m.) SOLITON-LIKE MODELS OF TRANSFORMATION PRECURSORS IN MARTENSITES: G.R. Barsch, Penn State University, University Park, PA 16802, and J.A. Krumhansl, Cornell Univ., Ithaca, NY 14853. Based on a previously developed Ginzburg-Landau theory we have studied various forms for the elastic potential (as a function of strain and strain gradients) in one, two, and three dimensions for martensites with cubic parent phase with the aim of describing the habit plane interface and transformation precursors. The heuristic value and the limitations of l-d models will be described. The available solutions and the nature and physical implications of the mathematical difficultie< associated with higher than l-d models will be discussed and some pertinent unsolved problems that require further experimental and theoretical work will be identified.
(g: 00 a.m.)
(11: 10a.m.)
ELECTRON-PHONON BASED LOCAL MODE DESCRIPTIONS OF DISPLACIVE
THE MARTENSITIC TRANSFORMATION - A CONOENSATION PROCESS OF SOLITONS T. Suzuki, Institute of Applied Physics, Tsukuba University, Sokura, Ibaraki, 305 Japan; C-Y Lei and M. Wuttig, Metallurgy Department, University of Missouri-Rolla, Rolla, MO 65401. The Martensite transformation can be viewed as a condensation process of sol itons. The sol iton associated with this structural phase transformation would simply be the boundary between the martens ite vari ants. Wh i 1e the martens it ic phase
TRANSFORMATIONS: G. "C. Abell, Monsanto Research Corporation, Miamisburg, OH 45342 As a general approach to the problem of precursive behavior in alloys that undergo a displacive transformation, defect theories are becoming increasingly popular. However. the microscopic origin of the proposed defects is usually not considered. Yu and
TMS Annual Meeting 17
corresponds to the condensed state of solitons, the austenitic phase corresponds to the molten state. The austenitic phase may be viewed as a dynamic average over the martensitic variants. Experimental support for this model is offered through internal friction studies of In-Tl single crystal reeds performed at finite amplitudes of oscillation in the temperature range Ms < T<: Ms + 70°C. These studies revealed a pronounced peak at these temperatures and at frequenc i es of 10H z <: f <: 180Hz. This peak is characterized by an activation energy of 1.2 eV/atom. Its nonlinear characteristics suggest that it is a boundary peak, i.e. that it represents the energy loss due to the motion of the solitons in the austenite.
(11 :40 a.m.) PRE TRANSFORMATION PHENOMENA AS REVEALED BY ELASTIC WAVES T. R. Finlayson, Dept. of Physics, Monash Univ., Clayton, Vlctona, Australia 3168. There ex is t s a number of examp 1es of ev i dence for the approaching onset of a structural phase transformation in a crystalline solid in studies of the dependence of sound velocity on a thermodynamic variable (commonly temperature). Such evidence is an anomalous temperature dependence for the velocity of a particular sound wave (and hence a specific elastic constant for single crystal data), which in some cases has aided our understanding of the phase transformation mechanism. Attenuation anomalies which are occasionally reported in conjunction with velocity anomalies are not so well understood. Several examples to illustrate pretransformation phenomena in both metallic and non-metallic systems will be reviewed.
PROCESS MINERALOGY APPLICATIONS TO PRECIOUS METAL DEPOSITS Sponsored by the TMS-SME Process Mineralogy Committee Monday, March 3,1985 La Galerie3 8:30 a.m. Marriott Hotel Session Chairmen: Donald M. Hausen, Newmont Exploration Limited, P.O. Box 310, Danbury, Connecticut 06810; Brenton M. Hamil, Mining and Geological Engineering Department, School of Mineral Engineering, University of AlaskaFairbanks, Fairbanks, Alaska 99775-1190
(9:30 a.m.) ORIGIN AND EXTENT OF THE GOLD, SILVER, ANTIMONY AND TUNGSTEN MINERALIZATION IN THE FAIRBANKS MINING DISTRICT, ALASKA: P.A. Metz and B.M. Hamil, Hineral Industry Research Laboratory D~Pt-. of Hining & Geol. Eng., Univ. of Alaska, Fairbanks, Alaska
and-
The Fairbanks Mining District in Central Alaska was discovered in 1902. Approximately 7.5 million troy oz. of placer gold, 250,000 troy oz. of lode gold, and several thousand short tons of antimony and tungsten have been produced from an area of about 400 square miles. Five main types of mineralization were recognized: 1) conformable, stratabound volcanogenic zinc, antimony, lead and copper sulfides in metavolcanics in places containing gold and tungsten; 2) complex precious metal-bearing lead sulfosalt-quartz veins in Cretaceous granitic intrusives; 3) tungsten skarns adjacent to granitic intrusives; 4) gold-bearing polymetallic sulfide-quartz veins crosscutting metavolcanics; and 5) antimonybearing gash veins along axial plane shears in metavolcanics. Fluid invlusions and isotopic data suggest different sources for each type of deposit, with a major metamorphic fluid content for all mineralization. Detailed description and evaluation of these occurrences are in progress.
(10:00 a.m.)
THE CASTROVIRREYNA DISTRICT,PERU: A SILVER-BEARING GEOTHERMAL SYSTEM: D.C.Poh1 American Museum of Natural History, Central Par~ New York, NY 10024 The po1ymeta11 ic silver depOSits of the Castrovirreyna district produce 1800 tpd ore gradin9 8-12oz Ag/t, 2% Pb and Zn with minor copper and gold from zoned crustified quartz-barite veins. Recent mapping has shown the veins to be part of an extensive fossil geothermal system in a late Miocene volcanic complex. Grades as well as ore and gangue minerals are strongly vertically zoned relative to the pa1eosurface as defined by relict silica sinters. Sinters, the immediately underlying collapse breccias and uppermost veins are relatively barren. Grade decreases with depth through the native silver, "ruby" silver, "black" silver zones to the tetr~ hedrite/enargite zone at which point it remains relatively constant. The upper silver-rich zones are frequently separated from the tetrahedrite zone by a 20-50m barren quartz zone. Recognition of a particular zone is a powerful aid to exploration strategies and planning.
(10:30 a.m.)
DRILL EVALUATION
COl.D ASSOCIATIONS I'r'! Ci\RLIN-TYPE CARBONACEOUS oP.[S:
OF NEWMONT
MINING CORPORATION'S RAIN
g~~ni !~,s;~~O N~8~~~i' E~~~~~~i i or,. E1~~;.~.. ~~~~ o;~80?: D.
(8:30 a.m.) D.M. Hausen,
J.W. Ahlrichs, H. Mueller, Newmont Exploration Ltd., 44 Briar Ridge Road, Danbury, CT 06810, H.C. Park, Technology Center, Cities Service Company, P.O. Box 3908, Tulsa, OK 74102
The exact mineralogic associations of gold in Carlin-type carbonaceous gold ores have been the object of considerable research in recent years, involving the use of various instrumental methods, Le., SEM, TEM, Electron Microprobe, Auger. etc., as well as the light microscope. Gold in primary unoxidized ores has been reported to occur submicroscopically in pyrite and organic carbon, as well as microscopically in quartz, carbonates and clays, and as free gold that probably ranges from several micrometers down into submicroscopic (colloidal) sizes. These varjous associations have been investigated in select carbonaceous ore samples, and described [rom the standpOint of relative abundance and metallurgical significance.
(9:00 a.m.)
~i!~e~in:t~~OQ~?g d~~~~lte~~~~~~da!io~~d!~e~ii~~~!~g
deposits
of
that includes the Carlin and Gold Quarry Mineralization is hosted in the Mississippian Webb Formation siltstone, which overlies the Devonian Devils Gate Limestone. Conventional and reverse-circulation percussion drilling methods were evaluated and compa""'ed in terms of thel"" relative ability to yield representative samples when drilling either wet or dry. Sample collection and splitting required great care because qold is bimodially concentrated in the coarsest and in the finest fractions of the drill cuttings. mines~
~~~nledrr~te~~~ty~rillin2ev~~~~~~ir~~~a~t~~lem:r~t~in~~
bet fer sample quality when drilling wet, especially iYI unstable ground, by minimizing wall-rock contamination. Wet samples were collected by passing the cuttings
~~~~~~t I~!7~~_~~~~~~~da c~g~~i1~~ai~1 i :~~r t~~r:ht~O'Jg~r~
samples were reduced in size by passing them through a Gilson Sample Splitter.
(11:00 a.m.)
SCANNING AUCER ~IICROPROBE ANALYSIS OF SUBMICRON FEATURES IN GOLD ORE FRON THE CARLIN ~lINE, NEVADA: H.S. liochella, B. Bakken, H.T. Einaudi. D.I\I. Harris, A.M. Turner, St~fo~-d~'U-~i-';ersity, Stanford, California 94305.
PLACER GOLD A.~D SILVER, S:;AKC RIVeR, SOUT:1EASTERN IDAnO George A. Desborough, William H. Raymond and Ralph P. Christian U.S. Geo!. Survey, Box 25046 HS 90S, Denver, CO 80225
I./e have used scanning Auger microscopy (SA."O as an ul tra-high resolution microprobe to study the mineralogically complex, goldbearing carbonate strata of the Roberts Hountain formation near Carlin, Nevada. SAH has the ability to perform near-surface semiquantitative chemical analysis with spatial resolution far better than the electron microprobe. Both the unoxidized and oxidized Carlin ores have been examined. The primary points of interest in the unoxidized ore, a carbonaceous silty limestone, are the pyrite surfaces, where the gold may be concentrated. Sl\l'1 depth profile analysis has sho\fIl that the iron oxide and sulfate passivation layers on the pyrite surfaces are between 200 and 400 angstroms thick. As of this time, we have not detected gold on these surfaces. (The 511.."1 detection limit for gold is approximately 0.1 atomic wt. %). Interesting features found by SAN in the oxidized are, Hhich has been hydrothermally leached and has a high clay content, are submicroscopic indium-containing oxides and sulfates, associated with quartz and hematite.
Placer gold has been known for more than 100 years in sand and gravel of the Snake River in southeastern Idaho. Prior to 1915, small scale placer mining of gold was attempted, but economic recovery was inhibited by the small grain size «Z50 micrometers). Several gold and silver minerals, including native gold, native silver, hessite (Ag2Te), stutzite (Ag5-xTe3 ) , aurostibite (AuSbZ), and amalgam have been identified in concentrates using ore microscopic, scanning electron-photomicrographic and electron-microprobe methods. Native gold grains occur in three principal forms as 1) delicately ornamented crystal aggregates, 2) flattened flakes and 3) rods generally less than ZOO micrometers in length. Our studies indicate that most of the gold and silver mineral s are first-cycle and have not travelled far from their source. The local source is one with native gold, silver tellurides, quartz and pyrite, judging from polymineralic grains.
18 TMS Annual Meeting a.m.) "I
'.
I
OF GOLD ACRES AND HORSE CANYON CARBONACEOUS
~
, CORTEZ, NEVADA: Robert D. Osmanson, Cortez Gold Mines, Cortez, Nevada 89821, Dr. Donald M. Hausen, Newmont Exploration Ltd., Danbury, CT 06810, Dr. J. Brent Hiskey, University of Tucson, Arizona 85721
(Y)
Substantial tonnages of refractory unoxidized protore reserves exist a t the Gold Acres and Horse Canyon mines. The resources contain from 0.5% to 1.5% organic carbon and from 1% to 2% sulfide sulfur, in a partially silicified carbonate host rock.
«
.r::. () ~
ro
~
>.
ro c
"0
Metallurgical research to develop a viable process has been ongoing for 15 years, and has included flotation, roasting, autoclaving, and chlorination. A study was initiated at Newmont's Danbury Lab and at the University of Arizona to identify gold's mode of occurrence and to aid in the development of a metallurgical treatment method. Carbon and pyrite flotation concentrates were characterized by reflected light microscopy, x-ray fluorescence, x-ray diffraction, and a search of sulfides and arbons was performed with microprobe. The findings are presented.
0 ~
carbide was also produced when calcia was loaded as a slag flux or as a raw material. It was found that the hydrogenation of the calcium carbide yielded calcium hydride and methane. Calcium hydride thus produced was used as a reducing agent of residual alumina in slags to improve the yield of metallic aluminum. The calcium hydride will be also usable for reducing titanium compounds.
(10:25 a.m.) ANALYTICAL METHODS FOR DETERMINATION OF SLAG AND METAL COMPOSITION IN CARBOTHERMIC PRODUCTION OF ALUMINUM:
A. F. Saavedra, C. L. Compton, L. M. Ruch; Reynolds Metals Company; Reduction Laboratory; P.O. Box 1200; Sheffield, Alabama
35660
In the experimental development of a process for carbo thermic reduction of alumina, it has been necessary to develop methods for accurately analyzing the products from the reaction between carbon and alumina. Determination of A1 C , Al 04C, Al 0 , 4 3 elemental AI, and C can be complicated by
~nter~erence Ee~ween
'. •
them. Methods for determining them have been developed at RMC-Reduction Laboratory and have been substantiated by X-ray diffraction.
•
TECHNOLOGY I: HISTORICAL REVIEW AND NEW PROCESSES Sponsored by the TMS Light Metals Committee Monday, March 3,1986 Poncthartrain Ballroom D 8:30a.m. Sheraton Hotel Session Chairman: Professor P. Sides, Carnegie-Mellon University, Chemical Engineering Dept., Pittsburgh, P A 15213
(8:30 a.m.) CHARLES HALL -
THE YOUNG MAN, HIS MENTOR, AND HIS METAL:
Norman C. Craig, Department of Chemistry, Oberlin College, Oberlin, Ohio 44074 The early history of the discovery and d~velopment of the Hall process for refining aluminum will be described. It beg1ns in the fall of 1880 when two young men met on the campus of Oberlin College. Charles M. Hall was a local youth who was self-educated in science and eager to make his mark as an inventor. Professor Frank F. Jewett was an exceptionally well educated chemist and mineralogist who had studied in Germany and taught in Japan. This account includes a reconstruction of the chemistry explored before Hall achieved the successful experiment on February 23, 1886. It ends with him producing the first ingot of aluminum in Pittsburgh on Thanksgiving Day, 1888.
(9: 15 a.m.) PAUL HEROULT -- THE MAN BEHIND THE INVENTION:
Bickert, 475 Steamboat Road, Greenwich, CT
by Christian
06836 1960
The destiny of a tanner's son, an inventor, a genial man, not just a "genius". This over-qualified man, at age 23, had to overcome his precociousness, gain acceptance for his electrolytic process, obtain financial backing for its industrial promotion. He wanted his invention to be the starting pOint, not the final goal, of his life's work, which he pursued in his own way. He had nothing of the typical scientific scholar: undisciplined, irreverent, funloving, fond of traveling, surprisingly inventive. No laboratories, no inscrutable scientific formulas, just flashes of insight, jotted down on bits of paper during a billiard game or a cruise at sea. Heroult imagined more than he invented, unfettered dreams, as witness his "running boat". He seemed an amateur, not a professional, but in the end he was more prolific than his colleagues in white coats. Behind the perfect invention emerged a sort of artistic performance--which was both his charm and his worth--and also what separated him from his friend and rival, Charles Martin Hall, whose destiny was so strangely similar.
(10:00 a.m.) BLAST FURNACE PROCESS FOR ALUMINUM, CALCIUM CARBIDE, CALCIUM
HYDRIDE, AND TITANIUM: M. Dokiya, M. Fujishige, H. Yokokawa, S. Ujiie, A. Motoe, T. Hirose, and K. Amano, National Chemical Laboratory for Industry, Yatabe, Ibaraki, Japan 305 Carbothermic reduction of bauxite was studied in a bench-scale 3 blast furnace (the inner volume of about 0.7m ). AI-Fe-Si alloys containing about 20-30% of metallic aluminum were produced when the concentration of oxygen at the center of furnace was reduced to extremely low extent (few percent) and 5he temperature of the furnace center was elevated more than 2000 C. However, about 4080% of aluminum in bauxite volatilized as dust. The addition of calcia was examined to trap and recycle the volatiles. Calcium
(10:50 a.m.) ELECTRODEPOSITION OF ALUMINIUM AT NEAR AMBIENT TEMPERATURES:
C.J. Smit and T.P.J. Peters Billiton Research B.V., P.O. Box 40, (Westervoortsedijk 67d) 6800 AA Arnhem, The Netherlands The e"lectrodeposition of aluminium at ambient temperatures from molten salt electrolytes has been investigated. The electrolyte studied consisted of a quaternary anunonium salt together with aluminium bromide and aromatic hydrocarbons, or together with aluminium chloride. High purity aluminium deposits (Al content ) 99.5 %) have been obtained in high current yield () 90 %) with these new room temperature molten salt systems. One melt, i.e. aluminium chloride/phenyltrimethylammonium chloride (molar ratio 2:1), in which the levelling agent is built into the ammonium salt itself, was studied in more detail. Several kinetic aspects of the aluminium deposition reaction from this melt, including the electron transfer process, the nature of the electro-active species and the incorporation of the deposited aluminium in the cathode, were investigated.
(11 :15 a.m.) COMPOSITE-ANODE ALUMINUM REDUCTION TECHNOLOGY: T. R. Beck, 1601
Dexter Ave. N., Seattle, WA 98109; J.C. Withers, 3770 Larrea Ln., Tucson, A2 85715; R.O. Loutfy, 4660 N. Via Madre, Tu~son, AZ 85749. Iterative improvements in the lOO-year-old Hall-Heroult (H-H) process have resulted in modern cells producing aluminum at about 6 kWh/lb. Further improvements in energy efficiency beyond a few percent are unlikely for the existing H-H process. The alternative chloride technology promises to produce aluminum at about 4 kWh/lb but requires a chemical plant to produce AICl 3 and bipolar cells. The chloride process is applicable to greenfield sites. A new process utilizing composite anodes also promises aluminum at 4 kWh/ib and design studies indicate that it can be retrofitted into existing H-H plants. The composite anode process consists of utilizing stoichiometric A1203-C anodes in a low temperature (e.g. 700 D C) bath. Unlike conventional H-H technology, a low alumina solubility in the bath is desirable and allows selecting chloride/fluoride bath compositions for minimum energy consumption. The process has been studied extensively on a 25- to 50ampere laboratory scale. A one-week run in a 2000-ampere pilot cell further demonstrated feasibility. Experimental results and projections of a commercial plant flowsheet will be presented.
SENSORS: DEVICES, MATERIALS AND PROCESSING I: Smart Sensors Sponsored by the TMS Electronic Devices and Materials Committee Bissonet Monday, March 3, 1986 Marriott Hotel 8:30a.m. Session Chairman: N. A. Gjostein, Ford Motor CompanyResearch Staff, P.O. Box 2053, Dearborn, Michigan 48121
(8:30 a.m.) SILICON MICROMACHINING TECHNOLOGY FOR SENSORS: Kurt E. Petersen, Consultant, 6244 Solomon Court, San Jose, CA 95123. A new technology has been under development in which high-
TMS Annual Meeting 19 precision, miniature mechanical components can be fabricated from single crystal silicon wafers. Silicon micromechanics is complementary to silicon microelectronics, employing many of the same processing techniques used in the integrated circuit industry . Although the manufacturi ng methods and des i gn criteri a are app 1 i cab 1e to many di verse mechani ca 1 functi ons and components, most of the successful commercial products have been phys i ca 1 sens i ng devi ces. Pressure sensors, acce 1erometers, mass flow sensors, acous ti c sensors, tacti 1e sensors, and hi gh vacuum sensors are a few examples of s il icon sens i ng devi ces whi ch have been demons trated. Thi s ta 1k wi 11 revi ew s il icon mi cromachi ni n9 and mi cromechani cs technologies, emphasi zi ng fabri ca ti on processes, i ntegrati on of e 1ectroni cs with mechanical structures, new concepts in silicon sensing devices and future trends in the app 1i cati on of s il icon mi cromachi ni ng.
(9:05 a.m.) Sensor Construction Via Deposited Thin Films, H. Guckel, Wisconsin Center for Applied Microelectronics, Unlverslty of Wisconsin, Madison, WI 53706. The integration of mechanical transducers into standard ICprocessi ng techniques requi res fundamentally the abi 1 i ty to fabri cate three-di mens i ona 1 structures wi th two-dimens i ona 1 tools. One can achieve three dimensions by adding two deposited layers to IC-processing. One of these is removed by lateral etching, i.e., it is a sacrificial spacer; and the other becomes part of the transducer body. This technique has been used to produce fully integrated pressure sensors. The selection of materials for this type of construction technique involves the mechanical properties of thin films. New techniques for the measurement of compressive and tensile strain fields have been developed. These tools are us·ed to as tab 1i sh process i ng procedures for fil ms wi th reproduceab 1e and des i gnab 1e mechanical characteri st i cs. Data from these measurements are used in computer aided des ign to produce predictable sensor performance.
(9:40 a.m.)
sensors. It is fast comparen to more conventional sensors. However it presents new and difficult prohlems of fabrication ann encapsulation not normally faced in the semiconrluctor fielrl. Theory of operation, fahrication methods, and applications will he discussed, alon~ with a recently developed multisensor chip with eight independent sensors and amplifiers and multiplexing.
THERMODYNAMICS AND PHASE STABILITY TMS-AIME General Abstract Session Monday, March 3,1986 Bissonet 8:30 a.m. Marriott Hotel Session Chairman: D. R. Gaskell, Dept. of Engineering, Purdue University, West Lafayette, IN 47907
(8:30 a.m.) A THERMODYNAMIC ANALYSIS OF THE Pb-S SYSTEM: R. C. Sharma, J.C. Lin and Y. A. Chang, Department of Metallurgical and Mineral Engineering, University of Wisconin, Madison, WI 53706. The Pb-S phase diagram has been calculated using an associated solution model for the Pb-S liquid phase and considering the intermediate PbS phase as a line compound. In the liquid phase, the existence of 'PbS' species is posu1ated in addition to the 'Pb' and '5' species in order to adequately describe the thermodynami c beha vi or of the 1i qui d phase. The a va i 1ab 1e thermodynamic and phase equil ibria data is simultaneously used to optimize the set of solution parameters for the liquid phase and for the Gi bbs energy of formati on of the PbS phase. The calculated Pb-S phase diagram agrees very well with the experimental data. The stabi 1 ity range of PbS is analyzed by a poi nt-defect model.
INTEGRATED SOLID-STATE SENSORS FOR AUTOMATED CONTROL SYSTEMS, K,D. Wise, Solid-State Electronics Laboratory, University of Michigan, Ann Arbor, Michigan 48109.
The emergence of low-cost but very powerful microcomputers has made the use of automation and electronic closed-loop control attractive for many applications, including those in biomedicine, transportation, and automated manufacturing. In most cases, the weak link in implementing such systems is the sensors, which must measure the parameters of interest with high sensitivity, selectivity, and stability, presenting an accurate and reliable signal to the processor while working in an often hostile environment. The sensors being developed for such applications are typically based on solid-state process technoll')gy and represent innovative cominations of silicon microstructures, thin-film materials, and custom integrated interface circuits. This paper will illustrate recent progress and current challenges in this area with three devices: an integrated multichannel microprobe for recording the cortical signals needed for neural prosthesis control; a 32-element silicon thermal imager for use in automated proces~ yontro ani a hig.h-performance tactile imager based on a capacltlve ce .
11'
(10:15 a.m.)
Break
(8:50 a.m.) AN AMBIGUITY IN THL iJEFINI1'ION OF THE ACTIVITY COEFFICIENT AT INFINITE DILUTION. J. P. Neumann and M. Venkatraman, Materials Department, University of Wisconsin-Milwaukee, f. O. Box 784, Milwaukee, WI 53201. Recently, a detailed analysis of literature data for the activity coefficient gamma of oxygen in dilute solutions of liquid copper was carried out. It was noticed that some authors defined the activity coefficient gamma at infinite dilution according to Henry's law whereas other investigators determined it by linear extrapolation of measured data to zero oxygen concentration. The implications of this ambiguity with respect to the thermodynamic description of solutions are discussed.
(9: 10 a.m.) STATISTICAL THERMODYNAMICS OF ORDER-DISORDER IN INTERSTITIAL ALLOYS: N. A. Gokcen, U.S. Department of the Interior, Bureau of Mines, Albany, Oregon 97321
(10:30 a.m.) SMART SENSORS: Richard S. Muller, Dept. of EECS, Univ. of Calif., Berkeley, CA., 94720.
The compatible fabrication of sensors with integrated circuits provides access to new designs for control systems that make use of available signal processing or IIsmart" capabilities. New applicatIons for active thin films and for the mechanical (as well as electrical) use of the silicon substrate and of polycrystalline thin films have led to important advances in the area of "integrated sensors." Some important research questions, in addition to those addressing device design, deal with Ie compatibility, optimal signal representation and conditioning, and discrimination of the desired signal in a noisy envirorunent.
A recent theory of order-disorder in alloys [N. A. Gokcen and E. T. Chang, J. Chern. Phys. 55, p. 2279. (1971); N. A. Gokcen, Scripta Met. 17, p. 53 (1983)f is modified for application to interstitial wlutions of hydrogen in metals. The results show that a single exchange energy is sufficient for the interpretation of experimental results for each hydrogen-metal system. The calculated values, based on the existing experimental data, are presented and discussed in detail.
(9:30 a.m.) ELASTIC EFFECTS ON SURFACE ENERGY: W.C. Johnson*, and P.W. Voorhees**, Metallurgical Engineering and Haterials Science, Carnegie-Mellon Universi ty Pit t sbu rgh, PA 15213 **Metallurgy Division, National Bureau of Standards Gaithersburg, MD 20899
(11 :05 a.m.) CHEMF~TS, Robert J. Huber, Dept. of Elec. University of Utah, S~1t Lake City, Utah 84112
Eng.,
The CHEMFET, Chemically Sensitive Fielr1 Effect Transistor, combines elements of analytical chemistry and semiconductor electronics to build small, rugged chemical sensors which respond quantitatively to a wide range of substances. It is an MOS Field Effect Transistor with the metal gate replaced with a structure which generates a voltage when exposed to the substance of interest. It is small, can be made part of an inte~rated circuit containing many independent
The thermodynamics of stressed solids provides a set of interfacial conditions that must be satisfied for the system to be in equilibrium. These conditions account for the interfacial stress, deformation, curvature, and structure as well as the excess quantities associated with the interface. These equations are used to examine the relationship between the misfit of a second phase precipitate and the interfacial energy. We show that increasing the magnitude of the misfit can either increase or decrease the interfacial energy depending on the deformation of the surface and the sign of the residual surface stress. This work is supported by the National Science Foundation and the Office of Naval Research.
20TMSAnnuai Meeting 9:50a.m.) IN U-NB: A THERMODYNAMIC ANALYSIS' J. C. Institute of Mining & Technology, Socorro;---NM; Sandia National Laboratories, Albuquerque, NM
thermodynamic feasibility of spinodal decomposition in U-Nb has been examined. To establish the post tion of the cal spinodal a thermodynamic analysis of the phase diagram nd other data has been performed. The thermodynamic model used modified subregular solution. The coherent spinodal has been etermined by including single crystal elastic constants. The ;hermodynamic analysis allowed for the calculation of the solid miscibility gap and chemical and coherent spinodals above monotectoid invariant (920 K). At 920 K, the calculated id state miscibility gap extended from 14 at.% to 73 at.% Nb, is in good agreement with the measured phase diagram, and ·cal spinodal extended from 27 at.% to 61 at.% Nb. The data Ibeen used to investigate age hardening mechanisms in U-Nb. *This work oerformed at Sandia National Laboratories sUDoorted
( 10: 10 a.m.) ELECTRONIC STRUCTURE CALCULATIONS OF BINARY ALLOY PHASE .DlAGRAMS* R.J. Hawkins, M.O. Robbins**, and J.M. Sanchez, Henry Krumb School of Mines, Columbia University, New York, N.Y. 10027, **Exxon Research and Engineering Co., C1 inton Township, Route 22 East, Annandale, N.J. 08801. A short-range order dependent electronic theory of coherent phase equilibrium in substitutional binary alloys is presented. The alloy internal energy is calculated using the C1uster-BetheLattice Method. The configurational entropy is evaluated uSing the Cluster Variation Method. The approach is parameter free and uses only the results of elemental electronic structure ca1cu1at ions as input. Equil i bri um phase di agrams for the Cr-W, Cr-Mo, and Mo-W systems are presented. We also calculate the chemical act iv it i es and hi gh- temperature enthalpy of fonnati on for the Cr-Mo system. The predicted phase diagrams and related thermodynamic functions are in good agreement with available experimental data. *This work was funded in part by NSF grant DMR-82-06l95
(10:30 a.m.) PROTOTYPE BINARY ALLOY PHASE DIAGRAMS FROM TIGHT-BINDING ELECTRONIC STRUCTURE CALCULATIONS: P. Turchi, A. Fine1,* M. S 1 u iter and D. de Fontaine, Department of Materi a 1 s Sc i ence and Mineral Engineering, University of California, Berkeley, CA 94720; *ONERA BP72, 92322 Chati 11 on, France Starting from a simple but real istic description of the electronic structure of transition metal alloys, we applied the results of the generalized perturbation method (GPM) to the computation of order-disorder phase diagrams by using the cluster variation method (CVM). Through the GPM, it is possible to express ordering energies in terms of concentration-dependent effective pair interactions. The GPM, which was originally invoked to study the relative stability of ordered structures at T = OK, when comb i ned with the CV M, offers a powerfu 1 too 1 to derive prototype phase diagrams. In particular, it wi 11 be shown that the general features which occur in experimental phase diagrams can be related to the behavior of the effective pair interactions, and hence to the relevant electronic parameters themselves.
(10:50 a.m.) A SOLID-STATE EMF STUDY OF THE QUATERNARY Fe-Co-S-O SYSTEI1: O. A. f.1usbah and Y. A. Chang, Department of 14etall urgica1 and HTnera1 Engineering, University of Wisconsin, Madison, WI 53706. The oxygen potential s of several three-phase and two-phase equi 1i bri a in the Fe-Co-S-O system as well as those of some twophase equilibria in the Co-S-O and Fe-S-O systems have been measured at PS02 = 1 atm using an emf method. From these n-easurements stability diagrams in terms of oxygen and sulfur potentials are constructed.
(11: 10 a.m.) THERMODYNAMIC ACTIVITIES AND PHASE EQUILIBRIA IN THE CaO-Ti0 2 BINARY SYSTEM: Mark Watkins and G. R. St.Pierre, Dept. of Metallurgical Engineering, Ohio State Univ., 116 W. 19th Ave., Columbus, OH 43210 The CaO- Ti O2 phase di agram has been analyzed us i ng a computer program which estimates liquidus curves for binary systems. The calculated curves are compared with experimental values found in the literature. The model assumes that the liquid is strictly regular and that solid solubility is negligible. The best combination of two adjustable parameters, the enthalpy of fusion and the nearest neighbor exchange enerqy, is selected by least
squares curve fitting. Calculated activities of Ti0 2 are presented for liquid compositions between Ti02 and CaTi0 3 at temperatures near 1550°C. For the deoxi dati on of i ron with titani um and cal ci um the equi1ibrium relationships between the henri an activities of Ca, Ti, and 0 have been calculated based on saturation with CaTi03 and TiO . The calculated activity functions are used to predlct the Z equllibrium phases formed by the deoxidation of iron with Ca and Ti at 1550°C. The experimental verification and practical significance of these results are discussed.
(11 :30 a.m.) STATISTICAL MECHANICS OF FUSED SALT SYSTEMS:
Gordon R. Holcomb
and George R. St. Pierre, Dept. of Metallurgical Engineering, Ohio State Univ., 116 W. 19th Ave., Columbus, OH 43210 A solvation shell model based on first nearest neighbor ions has
been developed for binary reciprical fused salts. Phase diagrams have been calculated from the resulting thermodynamic functions. The model is derived from a statement of the thermodynamic probability of the system, i.e., the number of ways the ions can be arranged into solvation shells. An entropy statement using the most probable arrangement of ions along with mass and energy balances has been used to derive the distribution of solvation shells which is consistant with the energy assigned to each shell. The configurational entropy of mixing, the enthalpy of mixing. and the Gibbs energy of mixing are calculated from the distribution of solvation shells. Phase diagrams are obtained by using the Gibbs energy of mixing for each phase as a function of temperature and composition. The resulting phase diagrams are compared with experimentally determined phase diagrams.
(11:50 a.m.) PHASE EQUILIBRIA IN THE Pd-Si SYSTEM:
R. D. Shull, A. J.
McAlister, M. J. Kaufman, National Bureau of Standards,
Gai thersburg, MD
20899
The equilibrium diagram of the Pd-Si system in the vicinity of the Pd-rich eutectic has been reinvestigated by differential thermal analysis (DTA), optical and transmission electron microscopy (TEM), and x-ray diffraction. Both rapidly solidified (metallic glass) and thermally equilibrated samples were studied; the advantages and disadvantages of both techniques will be discussed. Contrary to prior investigations, in the present study no metastable fcc Pd-rich phase was observed to crystallize from the alloys in the glassy state. Furthermore, the P2, structure, previously published for the PdSSi phase, was not observed in any alloy of the above com-
position region in any condi tion (equilibrium or non-equilibrium) •
TMI-2 ACCIDENT: CLEANUP PROGRESS AND VALUE TO INDUSTRY I Sponsored by the TMS/ ASM-MSD Nuclear Metallurgy Committee Monday, March 3,1986 Iberville 8:30 a.m. Marriott Hotel Session Chairmen: J. T. A. Roberts, Nuclear Power Division, Electric Power Research Institute, 3412 Hillview Avenue, Palo Alto CA 94303; Melvin L. Bleiberg, Advanced Energy Systems Division, Westinghouse Electric Corp., P.O. Box 10864, Pittsburgh, PA 15236
(8:30 a.m.) TMI-2 Recovery Strategy and Cleanup Progress: J.C. DeVine, Jr., GPUNC Tech. Plan, TMI-2 Admin. Bldg., Middletown, PA 17057; R.H. Fillnow, GPUNC, Govern. & Ind. Programs, TMI-2 Admin. Bldg., Middletown, PA 17057 Recovery from the TMI -2 accident has presented many unique management challenges for GPU Nuclear. In a situation of constantly
changing information on the extent of plant damage and radiological conditions a strategy was required which affords both considerable flexibility for rational response to new situations and sufficiently firm guidance to allow for task prioritization and wise conmitment of limited resources.
The GPUN strategy devised
established a three phase recovery program of stabilization, fuel removal and cleanup. Realistic options regarding ultimate plant disposi tion have been preserved to penni t corporate decision at an appropriate future time. GPUN is now well along in the second phase of recovery, "fuel removal". The significant cleanup progress accomplished to date to achieve this phase is reviewed.
TMS Annual Meeting 21
(11:15 a.m.)
(9:00 a.m.) TMI-2 TECHNOLOGY TRANSFER PROGRAM FOR U.S. UTILITIES J.T.A. Roberts, Electric Power Research Institute, 3412 Hillview Avenue, Palo Alto, CA, and F. L. Schwartz, EPRI Site Office, P. O. Box 376, Middletown, PA. EPRI manages a technology transfer program as part of the utility industry participation in the TM!-2 Recovery Program which is fully coordinated with DOE and GPU Nuclear. TM!-2 technology transfer is a "two way" process -- technologies developed as part of EPR! 's R&D program which might be of use in the cl eanup process are offered to GPUN for demonstration purposes, whil e data experiences and products developed by GPUN and its contractors are disseminated to other nuclear util Hies. EPR! uses a variety of media to get the message out to the industry. This paper reviews the experience to date with technical briefs, "ready now" documents, newsletters, and workshops. The products of the recovery effort which we bel ieve will contribute to improving the safety and rel iabil ity of this and the future generation of LWRs are al so discussed.
CESIUM RETENTION ON REACTOR HATERIAL SURFACES SlTHMARY OF
ACCIllE~T
AND TEST DATA; V. F. Baston, Physical Sd ences. Inc .• P. O. Box 1536. Sun Valley, 1D 83353; K. J. Hofstetter, GPU Nuclear Corporation, P. O. Box 480, Middletown, PA 17057; G. M. Buin, Babcock &. Wilcox, P. O. Box 239, Lynchburg, VA 24505, R. H. Elrick, Sandia National Laboratory, KAFB-EAST, AJbuquerque, NM 87185 The nature and distribution of retained cesium on rei1ctur material surfaces are pertinent to 50urce term evaluations and material decontamination. Chemical interaction of cesium radionuclides wi th rp.actor material surfaces have been reported for the TMI-2 accident (reference 1) and laboratory tests (reference 2). Correlation of these data indicate the amount of cesium retained by oxidized metal surfaces is directly proportional to the amount of silica present in the surface oxide. The extent of formation of the stabilized species depends on a number of factors, including the nature of the metal and oxide, the oxygen chemical potentia], and the gas/surface temperatures. The exact mechanisms and kinetics of formation have not been determined unequivocally; however, review of the t~st data and fundament a] principaJ s assist with identification of species, interaction energies, and rates.
(9:30 a.m.) DOE-SPCNSORED R&D A~ID TErH~IOLCGY TRPNSFER PROGRAMS, Dr. W. W. Bixby, DOE-TMI Site Office, P.O. Box Be, Middletown, PA 17057, J. R. Saunders, EGG Technical Integration Cffice, P.O. Box 8S, Middletown, PA 17057 The Pepartll'ent of Energy ~as been involved in the cleanup and recovery of the damaged Three Mile Island Unit 2 reactor since January 1 ~eo. In keeping with the Reagan Administration policies, the DOE program at HlI has placed considerable emphasis on "technology transfer" from the 90vernment laboratories to the plant owner General Public Utilities Nuclear Corporati on (GPUNC) and from ('PUNC through DCE/EG8C to the nuclear industry. This paper highlights the waste management technQ logy, developed in the government 1atoratori es, whi ch has been transferred to GPUNC and applied to solve the unique waste management problems at TH. In addition, the techniques used to communicate the generic aspects of the "lessons learned" from TM!-2 to the industry are also discussed in the context of equipment performance, operability and survivability.
UNDERCOOLED ALLOY PHASES I: (Hume-Rothery Memorial Symposium) Sponsored by the TMS Alloy Phases Committee Monday, March 3, 1986 Mardi Gras E Marriott Hotel 8:30a.m. Session Chairman: C. C. Koch, Materials Engineering Dept., North Carolina State University, Raleigh, NC 27695-7907
(8:30 a.m.)
Introduction of Hume-Rothery Awardee
(10: 15 a.m.)
(8:35_a.m.)
TMI-2 Core Examinations: Teclmiques and Results: E.R. Carlson, J.M. Broughton, EG&G Idaho, P.O. Box 1625, Idaho Falls, ID 83401; G.R. Eidam, GPUN, P.O. Box 480, Middletown, PA 17057 Exmr..ination of the TMI -2 reactor core began in 1982 when a closed
UNDERCOOLABlLITY AND THE EXPOSURE OF METASTABLE STRUCTURES:
cireui t television camera revealed extensive damage to the top of the fuel assemblies. From this initial observation a broad core
examination program has evolved to acquire core damage data during the reactor defueling process.
This examination program
includes photographic and ultrasonic documentation of the postaccident core condition, and sampling of the loose debris, fuel rod stubs, once-molten slag, structural components, and other
damage structures--including a unique method of core drilling to preserve the damage features prior to their alteration by defueling. TMI-2 samples are presently undergoing conventional hot cell examinations at several laboratories.
Examination results
to be discussed include: peak fuel temperatures, molten material production, high temperature core material interactions, fission product retention in the core debris, fuel rod fragmentation, control material reactions, and structural component damage. As-
yet unanswered questions about TMI -2 core damage and the plans for sampling and analyses to address them will also be reviewed.
The thermodynamic conditions for exposing metastable states are established by deenergizing a material, as in melt quenching, condensation, etc. When these conditions are met, metastable states may appear because they are kinetically preferred. The understanding of these kinetic preferences will be reviewed.Formation of metastable structures by melt quenching requires high kinetic resistance to crystal nucleation to deep undercooling in the "labi leU regime between the liquidus, and glass tempera ture, T g • Further, the growth of the most stable phase must be thermally activated and so quench suppressible if the metastable state is to persist at T < Tg • In metal systems selective alloying is crucial to the provision of the nucleation and/or growth resistance requisite to forming various metastable structures. These alloying effects will be surveyed and interpreted. *At present: B. T. Matthias Visting Scholar, Center for Materials SCience, Los Alamos National Laboratory, Los Alamos, NM.
(9: 15 a.m.)
(10:45 a.m.) Metallurgical Analysis of TMI-2 Core Damage: B.A. Cook, J.E. Stoyack, EG&G Idaho, Inc., P.O. Box 1625, Idaho Falls, ID 83401; D.E. Owen; Consultant, Hummelstown, PA 17036 During the TMI -2 accident, local core temperatures exceeded the melting point of the stainless steel and Zircaloy core components
(1700-1200 K) and, in some samples exceeded the melting point of the D02 fuel (3100 K). As a result, complex interactions occurred among the major metallic components--Zircaloy, stainless steel, Ag-In-Cd control alloy, and Inconel--including oxidation, solid state reactions, mol ten phase reactions, and interactions with
DO, and Al,O, ceramics. TMI-2 core damage analysis teclmiques, including in-vessel photography and testing and off-site microstructural and chemical analyses of fuel debris specimens have indicated the range of metallurgical reactions. The observed metallurgical reactions--grouped by temperature of occurrence-are reviewed and differences with laboratory predictions of reactions are noted.
David Turnbull,* Division of Applied SCiences, Harvard University, Cambridge, MA 02138
For the principal reactions, the physical
and mechanical properties of the reaction products and the implications for TMI -2 de fueling are discussed.
FUNDAMENTAL ASPECTS OF RAPID SOLIDIFICATION PROCESSING; Robert Mehrabian; College of Engineering, University of California, Santa Barbara, CA 93106. Poi nts of progress in current understandi ng of rapi d 1 i qui d to solid transformation will be reviewed. "Solidification rate" will be expressed in terms of interfacial velocities. Detailed consideration will be given to the interplay of supercooling and rapid heat extraction rate in controlling the mode and kinetics of sol idification processes. Achievable external heat extraction rates impose strict limitations on solid/liquid interfacial velocities in the absence of bulk supercooling. On the other hand, for the case of supercooling, the reca1escence rate at the interface almost always predominates the external heat-extraction rate. Attention will be directed to the resulting degrees of solute partitioning at the moving solid/liquid interface, and also to the special conditions which achieve partition1ess (or massive) solidification. The required conditions for the latter will be discussed in terms of phase diagrams (both equil ibrium and metastable) and the relative velocities of the interface and diffusion of solute in the liquid.
22 TMS Annual Meeting
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MONDAY PM
AND STRUCTURE OF UNDERCOOLED ALLOY MELTS: M. C •
emings, Y. Shiohara, Dept. Materials Science and Engineering, T, 77 Massachusetts Ave., Cambridge, MA 02139. The structure of undercooled alloy melts, especially of iron and nickel base alloys, typically varies continuously with increasing undercooling and then changes abruptly at a critical undercooling. Above this undercooling dendrites disappear and are replaced with a fine, non-dendritic structure. Solid phases present, their fineness, morphology. and composition depend on reoaling and on rate of heat extraction after nucleation. talk will describe structures and segregation that are typy found in undercooled alloy melts, and it will summarize in progress at M.l.T. to gain insight into the underlying chanisms of formation of these structures. As part of this rk, in situ measurements are being conducted on the solidifiion behavior of droplets of nickel base alloys using (1) high optical sensing, (2) high speed cinematography, and (3) resolution still photography.
.. . ~
Break
ALTERNATE ALLOYING FOR ENVIRONMENTAL RESISTANCE II: Sulfidation and Hot Corrosion Sponsored by the TMSIMSD Corrosion and Environmental Effects Committee Monday, March 3, 1986 Mardi Gras L-M 2:00 p.m. Marriott Hotel Session Chairmen: G. R. Wallwork, School of Materials Science and Engineering, The University of South Wales, P.O. Box 1, Kensington, Sydney 2033, Australia; and S. K. Banerji, Ferroalloys Division, Foote Mineral Company, Exton, PA 19341
(10:45 a.m.) SOLIDIFICATION OF UND£RCOOLEO ALLOYS: J. H. Perepezko, B. A. Mueller and K. Ohsaka Dept. of Met. and Min. Engineering, Univ. of Wisconsin, Madison, WI 53706. During solidification the amount of undercooling is an important factor in determining microstructural development by controlling phase selection during nucleation. Usually crystallization is initiated at a heterogeneous catalytic site at a relatively sma 11 undercoo 1 i ng. The use of fi ne droplet samples is an effective method of obtaining a sUbstantial increase in undercooling to the range (0.3-0.4)Tm• A number of factors have been identified which influence the undercooling in droplets; including: droplet coating, droplet size, cooling rate and melt superheat. Uti 1 i zi ng measured undercool i ngs over a range of cooling rates, transformation diagrams may be constructed for the operative solidification reaction. The maximum undercooling is limited by catalytic heterogeneous nucleation sites which can be exami ned under well defi ned condi t ions in two phase (1 +s) alloy droplets. With such samples specific reactions and product structures may be selected and metastable phase equilibria determi ned. The support of the NSF DMR 79-15802 is apprec i ated.
(2:00 p.m.) THE DEVELOPMENT OF OXIDATION-AND SULPHIDATION-RESISTANT FERRITIC ALLOYS
P. Tomas, P.R.S. Jackon and G.R. Wallwork. School of Materials Science and Engineering, University of New South Wales. P.O. Box 1, Kensington, Sydney 2033, Australia
Simple concepts of alloy design enable a degree of certainty in predicting the behaviour of alloys in aggressive, singlecomponent atmospheres at high temperatures. This has led to the development of a series of oxidation-resistant, alumina-forming, ferritic iron-based alloys containing aluminium, chromium and manganese. The oxidation characteristics of binary amd ternary alloys are discussed and oxide maps for Fe-Cr-Al and Fe-Mn-Al alloys presented. The application of similar concepts to the design of alloys for su1phidation resistance will be discussed. Examples of the scaling behaviour of ternary Fe-A1-X alloys in hydrogen-hydrogen sulphide gas mixtures are presented, and indicate similar morphological development in sulphide scales as in oxide scales. The development of alloys with protective sulphide scales is shown to be possible in the Fe-Nb-Al system.
(11 :25 a.m.)
(2:25 p.m.)
REVIEW OF UNDERCOOLING EXPERIMENTS IN LONG DROP TUBES: R. J. Bayuzick, Department of Mechanical and Materials Engineering, Vanderbllt University, Nashville, TN 37235, M. B. Robinson, George C. Marshall Space Flight Center, Marshall Space Flight Center, AL 35812.
THE REACTION OF IRON-ALUMINIUM ALLOYS IN MIXED GAS ATMOSPHERES.
Long drop tubes, that is tubes that are greater than 30 meters in height, have proven to be useful for the processing of metal s and alloys in a low gravity containerless environment on earth. Experiments have been performed on a reproducible, cost effective basis. Samples have been processed in both a high vacuum environment and an inert gas atmosphere. The latter has been particularly important for non-refractory metals and alloys in order to obtain significant undercooling within the limited free fall time of long drop tubes. However, large undercoolings have been observed in both refractory and non-refractory metals and ,alloys. Microstructural studies show a variety of interesting morphologies including both undercooling and recalescence effects.
The reaction kinetics of binary Fe-AI alloys containing up to 7.5 wt. percent aluminium in static anhydrous sulphur dioxide atmospheres have been examined by continuous gravimetric measurements. Optical and scanning electron microscope, electron microprobe and X-ray diffraction methods have also been used to characterise the scale morphologies. The influence of the partial pressure of sulphur dioxide on the reaction kinetics and kinetic measurements in dynamic sulphur dioxide atmospheres are in progress.
T.Y. Jang, S. Blairs and C.R. Wallwork, School of Materials Science and Engineering, University of New South Wales, P.O. Box 1, Kensington, Sydney 2033, Australia.
(2:50 p.m.) EFFECT OF ALLOY COMPOSITION Oh THE SODIUM-SULFATE INDUCED HOT-CORROSION ATTACK OF CAST NICKEI.-BASE SUPERALLOYS AT 900°C: C. A. Stearns, D. L. Deadmore, and C. A. Barrett, NASA Lewis Research Center, 21000 Brookpark Road, Cleveland, OH, 44135. Susceptibility to sodium sulfate induced hot corrosion was determined for 96 cast nickel-base alloy samples. A one-quarter rep 1 i cate of a 27 factori a 1 des i gn experiment was run to study seven compOSitional variables (Cr, Al, Ti, Mo, Ta, Nb and \1) at two concentration levels. All samples were tested for 300 one-hour cycles at 900 0 e in a Mach 0.3 burner rig flame containing 0.5 ppmw sodium. Samples were cross sectioned and the unaffected metal area was measured. Multiple linear regression analysis was used to determine an equation for estimating attack. Best corrosion resistance was found when Cr> 12 wt. :t but some lower Cr-content alloys exhi bi ted reasonable res i stance provided Al <2.5% and Ti > 4%. The effects of W, Ta, Mo and Nb were found to depend on Al and Ti content. Predicted attacks for the cOlrmercial alloys were calculated from the derived regression equation and found to be in agreement with experimenta lly measured va 1 ues.
TMS Annual Meeting 23
(3: 15 p.m.) HIGH TEMPERA TURE OXIDA liON/CORROSION OF IRON-BASE SUPERALLOY NASAUT-4GA1: F.D. Lemke/, j. G. SmeggiII, R. Bailey', J. C. Schuster 2 and H. Nowotny>' United Technologies Research Center, East 2 I Hartford, CT and University of Vienna, Austria A low cost (0.81$/lb) austenitic alloy, NASAUT-4GA1 (Fe-15Mn-15Cr2Mo-1.5C-1.0Si-0.5Nb w/o), was developed to meet Stirling engine component requirements, e.g. high strength and thermal fatigue resistance to 871°C, compatibility with hydrogen, good elevated temperature oxidation/corrosion resistance, and contain a minimum of strategic elements. The weight gains and resulting surface scales were measured and analyzed for specimens exposed to oxidation, sulfidation, and hydrogen environments at 871°C. During oxidation, a thin but tenacious silica layer was formed at the interface between the mixed oxide scales and the parent alloy. A protective spinel and a-Fe20, phase formed during sui fidation tests using Na2S0, coatings. Preferential attack of the carbide phases by hydrogen was not observed after 350 hrs. Work was supported by DOE/NASA under contract DEN3-2B2.
(3:40 p.m.) HCYr SALT CORRUSION RESISTANCE OF FEMNAL ALLOYS: Ching-Haai KaO,
Jen-Jung Chan,Chi-Meen Wan, and Shin-Chin Chang, Institute of Material science and Engineering ,National Tsing Hua University Hsinchu, Taiwan, R.O.C. A series of Femnal alloy with or without the addition of 1% carbon and 3% chromium are chosen for the specimens into the hot salt bath ~urnace. The experiment are performed in the commencc ial medium temperature salt, Q-6, at 600 and 80a e. The chemical composition of Q-6 contains BaC1 , KCl, Liel, etc. Average 2 penetration depths and thickness losses after isothermal hot corrosion approximately assessed from the microscopic examination of metallographic cross-sections. X-ray diffraction and electro probe microanalysis (EPMA) are also used for the analysis of the final scales. The results are discussed in terms of possible mechanisms .
(4:05 p.m.) ROLE OF MOLYBDENUM IN THE Na2S04 INDUCED CORROSION OF SUPERALLOYS AT HIGH TEWERATURES: A. K. Misra, NASA Lewis Research Center, 21000 Brookpark Road, Cleveland, OH. Mo is known to induce catastrophic corrosion of superalloys in the laboratory hot corrosion studies; however, there is considerable controversy regarding the effect of Mo in actual engine conditions or even in the high velocity burner rigs. In the laboratory salt spray tests, the corrosion is due to the format ion of Na2Mo04-Mo03 and Na2S04-Na2Mo04-Mo03 for 1 atm 02 and 02+S02-S03 atmospheres respectively. Rapid corrosion is bel i eved to occur by electron i c conduct i on through Mo03 cortaining melts. For PS0 3 in the atmosphere greater than equilibrium PS0 3 for the reaction: Na2S04+Mo03 = Na2 Mo04+S03, no catastrophic corrosion was observed. Corrosion studies of a molybdenum containing superalloy were also performed in a high velocity burner rig, and a comparison of the results from the high velocity burner rig with that of the laboratory salt spray tests will be presented. Also the corrosion mechanisms in the high velocity burner rig will be discusspn.
(4:30 p.m.) TURBO 25 NICKEL BASE SUPERALLOY: M. K. Tripucka and J. R. Mihalisin, Howmet Turbine Components Corp., Alloy Division, P.O. Box 371, Roy Street, Dover, New Jersey 07801.
dissolution, the sample is analyzed for the major and minor elements using La and Y as their respective internal standard in matrix matched calibration solutions prepared from synthetic standard solutions or from dissolution of a standard reference material. This procedure permits better control of the factors influencing the precision and accuracy of the measurement. The technique adopted and the results obtained will be presented and discussed.
(2:20 p.m.) AUTOMATIC ON-LINE MEASUREMENT OF MOISTURE CONTENT AND SURFACE
AREA OF ALUMINUM OXIDE: Kaiser Aluminum CA
94S66,
(415)
&
R. M. Pearson, L. Ryhti, and C. JOb, Chemical Corp., 6177 Sunol Blvd., Pleasanton,
462-1122.
This paper will introduce a practical on-line method of measuring both moisture content and surface area of reduction grade aluminum oxide as i t exits either a rotary kiln or a fluid bed calciner. A nuclear magnetic resonance (runr) spectrometer, especially built for on-line measurements, will be described. Accurate moisture measurements in reduction grade ore can be closely correlated to the surface area of this material. The molecular structure and its effect on the nuclear magnetic resonance spectrum of aluminum oxide will be discussed.
(2:45 p.m.) PROCEDURE FOR ALUMINA ATTRITION INDEX TEST: C. K. Matocha and J. H. Crooks, Alcoa Technical Center, Alcoa CenteGPI'\T5069 The traditional Forsythe-Hertwig procedure for determining the attrition characteristics of alumina was investigated to determine and assign the causes of analytical variability. The apparatus was improved to simplify the mechanical aspects of the test and to standardize the high-pressure air jet. Test variables investigated include: orifice diameter, inlet air pressure, air flow rate, control of orifice pressure drop, attrition time, and sample charge weight. In addition to evaluating the present operating conditions, comparison tests to ascertain electrostatic effects are reported using samples that were equilibrated at 447. R.H. (Water sorption procedure) and using an air jet of humidified air .
(3: 10 p.m.)
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(3:25 p.m.) DETERMINATION OF SPECIFIC THICKENER AREA REQUIREMENTS FOR SYNFLOC-FLOCCULATED RED MUDS USING A TRAVERSING GAMMA-RADIATION DENSITOMETER: R. D. BraSSin%a and G. D.Fulford, Alcan International Limited, KIngston, ntario, Canada K7L 4Z4. Instrumentation has been developed with the cooperation of Atomic Energy of Canada, Ltd., to permit the determination of a series of density profiles at selected intervals of time during the laboratory batch settling of flocculated red mud and other slurries. This is done by traversing a 137Cs source and radiation detector past an undisturbed column of the slurry undergoing compaction. The density profiles are readily evaluated to predict the specific area requirements for continuous thickeners as functions of the flocculant dosage and the desired underflow sol ids concentrations. Examples are given to illustrate the use of the equipment to evaluate the effects of various types and dosages of flocculants, etc., with respect to the thickening of various red muds and other slurries in conventional and high-flux type thickeners.
(NO ABSTRACT AVAILABLE) (3: 50 p.m.)
ALUMINA AND BAUXITE II Sponsored by TMS Light Metals Committee Pontchartrain Ballroom A Monday, March 3,1986 Sheraton Hotel 2:00p.m. Session Chairman: F. Kimmerle, Alcan International Limitee, Laboratories Arvida et Centre de genie experimental, C. P. 1250 Jonquiere, Canada G7S 4K8
SYNTHETIC FLOCCULANT TECHNOLOGY IN THE BAYER PROCESS: Lawrence J. Connelly, David O. Owen, Paul F. Richardson, Nalco Chemical Company, 1601 W. Diehl Road, Naperville, Illinois 60566
Synthetic polymers of acrylamide and/or sodium acrylate have gained use over the last several decades as flocculants in solidl"iquid separation processes in the mining industry. In the last decade or so these polymers have also successfully replaced a large portion of the starch that has historically been used as a flocculant by the bauxite industry. In this paper, the structureactivity relationships observed in other mineral processing industries will be related to that seen in the bauxite industry. The influence of polymer molecular weight (or size), polymer composition, mode of application, effect of alkalinity, flocculant activity and other factors, will be reviewed.
(2:00 p.m.) (4:20 p.m.) THE: USE OF INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION SPECTROSCOPY (ICP-AE) FOR THE ANALYSIS OF RAW MATERIALS AND FINISHED PRODUCTS IN THE ALUmNUM INDUSTRY: Kwat The, Alcan International Ltd, Arvida Laboratories, C.P. 1250, Jonquiere, Ouebec, Canada G7S 4K8
REACTIVITIES OF ALUMINUM HYDROXIDE WITH ACID AND CAUSTIC SODA: K. Yamada, M. Yoshihara, Sumitomo Aluminium Smeltinq Co., Ltd., Nllhama, Japan
ICP-AES techniques have been developed for and applied to the analysis of raw materials and finished products. After suitable
Aluminum hydroxides with different primary and secondary crystal sizes were prepared. Primary and secondary crystal sizes were
24 TMS Annual Meeting n ranges of 0.3 - 5q,m and 0.3 - l20um respectively. activities of these aluminum hydroxides with hydrochloric id, sulfuric acid, and caustic soda solutions were measured. e effect of primary crystal size on the reactivity is stronger that of secondary one.
COMPLEX CAUSTICIZATION AN UTICI[NT )IEANS [-OR RlUUCING ,'JDOH-LOSSES IN TII[ ALUMINA PRODuCTION Gy. Baksa, F.Vu116, F. Sitkei, Alumino Plant, H-8401 Ajku, J. Ziiluli, K. Solymur', ALUT[I{V-FKI I'.O.80x.128. -1389. 8udupes t processin~ hiGh silicD IG to 7 'luI content bauxite 8ayer process, the cost of Nomi used up in the urse of alumina production is
ilpIH'OX.
20
to 25 %
the production cost. Aport from the so-coIled ound caustic soda losses due to the reactive 5i02 ontent, serious problem nlso al~ises in the course f reCover iny NU2C03 bu i 1 t up in the pl'ocess 1 i'luor.
new solution will be disclosed in the paper for he reduction of cuustic soda losses in tile dlumina I'oduction. Main feature uf the complex cuusticizution linked to the washinu prucedure of red mud is the sinGle-opel'ation causticization of the sodium uluminium hydrosilicote content of I'ed mud ond the dissolved Na2C03 content, moreover the efficient washing off of the cousticized mud.
CARBON TECHNOLOGY II Sponsored by the TMS Light Metals Committee Monday, March 3,1986 Pontchartrain Ballroom C 2:00 p.m. Sheraton Hotel Session Chairman: Jean-Paul Huni, Alcan International Limited, P.O. Box 1250, Jonquiere, Quebec, Canada G7S 4K8
on the change of rheological properties of pitch/coke mixtures during mild thermal treatment with special regards to the operation conditions in Soederberg plants. A testing method is presented which provides supplementary infomation about the ageing behaviour of pitch in contact with coke particles in order to develop new, tailored pitch qualities for improved anode performance in Soederberg ce 11 s.
(4:00 p.m.) THE RESTRICTIVE EFFECT OF SECONDARY QI IN BINDER PITCH TOWARDS THE EXPANSION OF ELECTRODES DURING CALCINING: Toshimasa Kagajo, Katsumi Fujita, Makihiko Mori: Torishiwa Works-,llSiil
(4:30 p.m.) INFLUENCE OF VANADIUM ON ANODE QUALITY AND POT PERFORMANCE W. Schmidt-Hatting, SWISS ALUMINIUM LTD., P. O. Box 495, 8034 Zurich, R. Perruchoud, J. E. Durgnat, SWISS ALUMINIUM LTD., 3965 Chi ppi s, Swi tzerl and. Normal vanadium contents in electrode cokes are mostly below 200 ppm. When crude oils with higher degrees of contamination are processed, the vanadium content can rise considerably. PUblications report that the result is an increase in the anode airburn and a drop in the current efficiency. To investigate the influence of vanadium systematically, anodes were produced with 400 ppm vanadium and set in prebaked reduction cells. Standard anodes with approx. 120 ppm vanadium were used by way of comparison in identical cells. The higher vanadium content had, as mentioned, the effect of lowering the current efficiency by more than ha If a percent and of ra is i ng the non-electro 1yt i c anode consumption by 7 %. All tests took place in close co-operation with INTEVEP, Los Teques, Venezuela, the goal being to investigate how cokes from high vanadium containing Vanezuelan crude oils can be used in the Aluminium Industry.
(2 :00 p.m.) PYROLYSIS OF GREEN CARBON ANODES: A. Charette and F. Tremblay: UniversiH du Quebec a Chicoutimi, Chicoutimi, Quebec, Canada G7H 2Bl, E. Dernedde and S.K. Nadkarni: Alcan International Lir;]ited, Arvida (Jonquiere), Quebec, Canada, G7S 4K8. During the industrial baking of green carbon anodes, volatile matters consisting mainly of methane, hydrogen and heavy hydrocarbons are released. These volatiles are sucked in the flue where their combustion can contribute in SOme instances to 40" of the energy required for the baking. Good knowledge of the pyrolysis kinetics thus becomes very important if one attempts to develop a mathemat i ca 1 model of a ri ng furnace. I n order to obtain the desired information, we have performed non-isothermal thermo-gravimetric tests on chosen samples in a specially built apparatus. The set-up can analyse samples up to 200 grams. Studies include the effect of sample dimensions and rate of heating. A kinetic equation is proposed for the pyrolysis and a discussion is presented on the applicability of these laboratory results in real situations.
(2:00 o.m.) NEW PROCESS OF DI~ECT METAL RECOVERY OUT OF DROSSES IN THE ALUMINUM CASTHOUSE: G. Zahorka, Al uminum Pechiney BP 24, 38340 Voreppe, France. ----
(2:30 p.m.) STRUCTURAL CHANGES OF COKeS DURING DESULPHURIZATION: S. R. Brandtzaeg 1) ,2) and H.A. 0ye: 1) Institute of Inorganic Chemlstry, Norwegian Institute of Technology, University of Trondheim, N-7034 TRONDHEH1-NTH, Norway. 2) Ardal og Sunndal Verk a.s., R&D Carbon, N-5875 ARDALSTANGEN, Norway. Structural changes during desulphurization of three petroleUm cokes and one pitch coke with original sulphur content in the range 2.5-0.4 'I, have been studied. Double peaks in the 002 reflection profiles were observed for all petroleum cokes calcined in the region 1500-16750C where a sharp decrease in sulphur content occurs. The mechani sm of graphit i zat i on is di scussed.
(3:00 p.m.)
CAST SHOP TECHNOLOGY AND RECYCLING II: Skim Processing and Recycling Sponsored by the TMS Light Metals Committee Monday, March 3,1986 Pontchartrain Ballroom B 2:00 p.m. Sheraton Hotel Session Chairman: J. M. Creel, II, Reynolds Aluminum, Reynolds Metals Company, Richmond, VA 23261
Traditional methods of aluminum recovery out of drosses mean: transportation outside the casthouse, high energy consumption and pollution problems by fumes and dumping of oxides and salt. The newly developed process pemits extraction of liquid metal by simple compression of drosses, The recovery rate is better than any other known processes, whi 1 e cost is Inuch lower. Industrial tests have establ ished that al uminum extraction by compression can be carried out on drosses of all major alloys, and is compatible with standard remelt or alloying procedure of each casthouse or foundry. Other advantage: The metal can be recycled immediately in the same furnace.
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(2: 25 p.m.) THE USE OF INERT GAS FOR DROSS COOLING, A.B.
(3:30 p.m.) AGEING AND RHEOLOGltAL P~OPERTIES OF 81NDER PITCHES: A. Al scher and II. Gemme"e: VfT, Verhaufsgesell schaft fOr Teererzeugnisse mbH, tlOO Duisburg 12, FRG Germany. F.Alsmeier and R. Marrett: ROtgerswerke AG, R + D Center, 463 CastropRauxe 1, FRG Germany. The paper deals with ageing and rheological prol'erties of binder pitches. Special emphasis is layed on the influence of ageing
Innus,
Ingot
Products Division, Alcan Smelters and Chemicals Ltd., Jonquiere, Quebec, Canada.
The combined application of an argon gas atmosphere and a segmented dross bucket is discussed. The exclusion of air from the dross by argon under a bell arrests and prevents exothermic oxidation of aluminum, while the specially desiuned bucket absorbs the dross heat. A one ton load of dross can be cooled to below 750 0 F {yODOe} in under y hours. An approximate 50~ improvement in recovered metal was experienced relative to
TMS Annual Meeting 25 dross room cool ing. The system is compared to other dross cool ing systems in terms of safety, envi ronrnent, costs and metal recovery. The inert gas system has been chosen as a replacement to dross room cool ing for an Alcan casting center with a 1500 tpa dross throughput. The projected capital cost was about half of the other systems considered.
(2:50 p.m.) MELT LOSS EVALUATION, J. H. L. van Li nden, Al coa Technical Center, Alcoa Center, PA 15069, H. G. Reavis, M. H. Widmer, Aluminum Company of America, 1501 Alcoa Ruilding, Pittsburgh, PA
15219. Melt loss is one of the highest and also one of the most elusive cost factors in an aluminum remelt plant. Several definitions have been developed to accurately describe the various phenomena that cause loss of metal during process i ng. Melt loss tests under strictly maintained conditions with a number of "key" scrap types provide a framework for establishing a total plant melt loss number. After having thus set a standard, the performance can he monitored or the melt loss consequences of change in product mix can he pred i cted.
(3: 15 p.m.) FUNDAMENTALS OF DECOATING OF ORGANICALLY COATED ALUMINUM SCRAP: by N.r. Fitzpatrick and J .G. McCubbin. Alcan International Limited. Kingston. Ontario. Canada. and J.F. Evans. Alcan Rolled Products Company. Oswego. New York. U.S.A.
The thermodynamic properties of various coatings used in the canning industry are discussed and the results of an isothermal test to determine the rate of removal of coatings from aluminum are presented. Various types of plug-flow reactors are considered and it is concluded that a cross-flow moving bed reactor is most appropriate for decoating can scrap. The measured velocity and temperature rise of heat pulses through such a bed are compared with theoretical values to demonstrate the predictabil ity of the reactor selected.
(3:40 p.m.) METHODS FOR UPGRADING COMMON SILICATE REFRACTORIES AND FOUNDRY IRON IMPLEMENTS AGAINST THE ATTACK BY MOLTEN ALUMINUM ALLOYS:
B. Gnyra, Alcan International Limited, Kingston Research and Development Centre, P.O. Box 8400, Kingston, Ontario, Canada, K7L 4Z4. Most of the so-called consumable refractories can be protected from molten metal chemical attack by a simple surface treatment with a water solution of a single salt, designated as F(C) solution, and/or a combination of a water slurry of refractory powder mixtures and F(C), designated as SNF treatment; both of which are readily prepared from common commercial materials. The proposed proprietary refractory/metal protection process offers a comprehensive economical package for treating insulated troughs, transfer boxes, filters, hot iOPS dip tubes, fluxing tubes etc., especially, when handlin~ high j y aggress;"e aluminum alloys, notably 4.5% Mg/Al and 2.5" Li fAl alloys. Since the Solutl0n/slurry treatment of refractories imparts to them excellent long-lasting non-wetting properties, there is no need to use additional protective washes such as mica, wollastonite, boneash, etc. that might be highly objectionable when metal cleanliness is of concern.
(4:05 p.m.) THE ELKEM LADLE CLEANER. DEVELOPMENT AND OPERATING RESULTS: K. H. Strom Elkern Technology, Inc., P. O. Box 177, Pittsburgh, PA 15230. Elkem a/s is one of Norways largest industrial companies. Through the operation of two aluminium smelters Elkem has been faced with new economical and environmental requirements which affect the field of ladle cleaning. In order to meet these requirements, the ELKEM Ladle Cleaner was developed. The results obtained by operating the ELKEM Ladle Cleaner were very satisfying and Elkem decided to market the equipment through Elkem Engineering. The lAdle to be cleaned is turned upside down and fixed to a rotating ring on the top of the machine. The ladle side walls and bot'tom are then cleaned by a hydraulic driven vertical operating mill cutter. The chip pings are collected in removable containers for return to the smelters. The investment has proved very profitable. Several years of operational experience confirm reduction in production cost and show high profit on invested capital.
(4: 30 P .111.
)
TECHNOU1CICAL A~ll ECO~O)1IC JUSTlFICATIOI\ FOR REPLACING OR MODERNIZING EARLY GENERAllON COI\TINIlUS-PROPERZI NONFERROUS ROD LINES. PAUL K. RAIFORD, P]{ESlDENT, PROPERU INTERNATIONAL, INC., 5328 TREMONT AVENUE, DAVENPORT, IOWA 52807 DURIN(; THE PAST 40 YEARS TIlE CONTINUUS-PROPERZI COMPANY HAS SOLD OVER 300 NONFERROUS CONTINUOUS CASTING AND ROLLING LINES FOR THE PRODUCTION OF LEAD, ZINC, ALUMINUM, AND COPPER WIRE ROD. ABOUT 150 OF THESE PROPERZI LINES ARE IN THE AGE RANGE OF 20 TO 30 YEARS AND ARE MOSTLY IN INDUSTRIALIZED COUNTRIES, REFERRED TO AS DEVELOPED NATIONS OF THE WORLD. DURING THE PAST 10 TO 15 YEARS, MANY TECHNOLOGICAL ADVANCES HAVE BEEN MADE IN CONTINUOUS CASTING AND ROLLING NONFERROUS ROD PRODUCTION. THROUGH THE USE OF SLIDES, PHOTOGRAPHS, TABLES, AND CHARTS, THE AUTHOR WILL ENDEAVOR TO ILLUSTRATE AND EXPLAIN THE TEGHNOLOGICAL AND ECONOMIC REASONS THAT PROPERZI OPERATORS 11\ INDGSTRALIZED COUNTRIES OF THE WORLD MUST BEGIN VERY SOON TO REPLACE OR UPGRADE THEIR 20 TO 30 YEAR OLD PLANTS.
COPPER, NICKEL, COBALT & PRECIOUS METALS II: HIGH PURITY METALS Sponsored by the TMS Copper, Nickel, Cobalt & Precious Metals Committee Monday, March 3,1986 La Galerie 5 2:00 p.m. Marriott Hotel Session Chairman: M. C. Jha, AMAX Extractive Research & Development, Inc., 5950 McIntyre Street, Golden, CO 80403
(2: 00 p.m.) HIGH PURITY POLYCRYSTALLIKE SILICON PRODUCTION FOR ELECTRONIC Dr. James R. McCoTwick, Hemlock Semiconductor APPLICATIONS: Corporation, Hemlock, Michigan
The hydrogen reduction of trichlorosilane has been the dominant process used in the production of electronic grade polycrystalline silicon for more than two decades. During this time period, industry capaci ty has increased by nearly three orders of magnitude to approximately 6000 T/Y. Technology improvements coupled with economies of scale have resulted in steadily declining product price during this time frame. While product price has been declining, product purity has been constantly improving to meet the demanding requirements of the integrated circuit industry. The overall production process, including production of the trichlorosilane intermedi:.te as well as the poly crystalline silicon deposition process, is discussed. Emphasis is placed on general process operations. Product form and purity are reviewed along with the key analytical methods used to characterize the high purity polycrystaJline silicon.
(2:25 p.m.) ;jELT SEPARATION OF SOLAR GRADE SILICON FROH SODIUM FLUORIDE: L. Nanis, Xebec Corporation, 2221 Old Oak Road, San Jose, CA. 95131; A. Sanjurjo, SRI International, 333 Ravenswood Avenue, Hen10 Park, CA. 94025 High purity silicon and NaF produced by the Na reduction of SiF can be melt-separated by heating the mixture to 1450°C. Batch melt separations of up to 6 kg of reaction products were performed successfully with complete separation of Si. S1 coalesces into a pool below a layer of NaF. In the presence of NaF, Si does not h'et the graphite crucible, thus avoiding SjC formation. The surface tension of molten silicon wetted by NaF ..laS estimated from drop geometry to be 320 + 20 erg cm- 2 The purity of the S1 obtaIned by melt separatio~ was aI~alyzed by Spark Source Mass Spectrometry, Plasma Emission Spectroscopy and Neutron Activation Analysis and found to be suitable for solar cell manufacture.
(2:50 p.m.)
*
METAL PURIFICATION BY SOLID STATE REFINING TECHNIQUES: o. N. Carlson, Ames Laboratory and Dept. of Materials Science and Engineering, Iowa State University, Ames, IA PrinCiples and application of electrotransport, external gettering and vacuum degassing in the solid state purification of metals. Selected examples of applications to refractory, rare earth or transuranic metals. Primary emphasis of paper is on electrotransport, describing the scope and limitations of this technique for a variety of metals. Discussion of use of residual resistivity as a characteri:z:ation method. Possible technological applications for high purity metals. *This work was supported by the USDOE, Office of Basic Energy Sciences, Division of Materials Sciences.
FICATION OF CADMIUM AND TELLURIUM BY ZONE REFINING*: R. F. R. P. SuIt, A. B. Ballang, Corninea Electronic Materials,
Ltd., Trail, B. C., Canada VIR 4L8 techniques were examined to further purify existing of high purity Cd and Teo Zone refining with a CdTe n was most interesting. By spark source mass spectros(SSMS), it was shown that adding CdTe to Cd, prior to zone refining, enhanced the segregation behaviour of In. An observed increase in ductility of the cadmium indicated that the concentration of soluble impurities was reduced. SSMS observations demonstrated that the segregation of Ga, As, K, and Ca were beneficially modified when using a similar CdTe additive procedure for Te.
the presentation, details of the purification technique will discussed. The electrical results of CdHgTe crystals prefrom the additionally purified precursors will be compared crystals grown from commercially available feed material. This work was supported by funds received by a Canada - U. S. Defence Cost Sharing Program.
(3:40
p.m.'
HIGH PURITY METAL AND METAL OXIDE PCWlERS BY SPRAY-DEC:CMPOSITION OF CHIDRIDES: W. Karner and H. Krivanec, Arus Andritz-Ruthner, Inc., Pittsburgh, PA
toughness) and crack growth (i.e., resistance curves) in engineering materials. Examples are drawn primarily from meta 11 i c and cerami c systems, where it is shown that the principles underlying the development of fracture resistance often are sharply in contrast. This distinction between the alloy design of brittle and ductile materials for maximum toughness is discussed in detai 1.
(2:30 p.m.) SPECTRUM FATIGUE CRACK GROWTH BEHAVIOR OF 2000 AND 7000 SERIES ALUMINUM ALLOYS: G.R. Chanani, G.V. Scarich and K.M. Bresnahan Northrop Corporation, Aircraft Division, Hawthorne, CA 90250 USA Spectrum fatigue crack growth (SFCG) behavior of 2000 and 7000 series aluminum alloys was determined, and the fracture characteristics of these alloys were correlated with the microstructural features. In each of the two alloy series, the effects of various alloying approaches including purity and temper on SFCG were detennined. SFCG tests were conducted using two different spectrums representative of ai rcraft structures. One spectrum was domi nated by tens i 1 e loads and the other spectrum had a s i gnificant number' of high magnitude compressive loads in addition to tensile loads. The latter spectrum was then modified by e1imi nat i ng compress i ve load sin order to dete nni ne t he effect s of compressive loads. Constant amplitude fatigue crack growth (CAFCG) behavior was also determined for comparison to the SFCG behavior. The presence of large constituents in the microstructure caused an increase in both the CAFCG and SFCG rates at high stress intensities. The overall fatigue crack growth life was affected by the type and size of metastable precipitates.
Spray roasting teclmology which has been used for pickle acid
regeneration for many years can be successfully applied for the production of high purity rretal oxides and metal pcMders.
Purification steps can be applied to remove unwanted impurities roth in the solution stage and on the oxide product. The process has a high p::>tential of producing mixed oxides and metal alloy powders. Examples will be given on industrial plants and pilot plant reduction tests, as well as properties of oxide and rretal ])C)I.o.tiers.
\4:05 p.m .' RECOVERY OF PURE NIOBIUM AND TANTALUM OXIDES FROM A PYROCHLORE CONCENTRATE: G. M. Ritcey, R. Molnar, and B. H. Lucas, CANMET, 555 Booth Street, Ottawa, Canada KIA OCI
A process is described for the treatment of a pyrochlore concentrate by dissolution in HF and H2S04, followed by purification of the clarified leach liquor using solvent extraction. Niobium and tantalum are co-extracted into tributyl phosphate. The solvent is stripped for niobium with ammonium fluoride and the niobium is subsequently recovered by precipitation with ammonia. Tantalum is then stripped from the organic with ammonium carbonate and recovered by precipitation also with ammonia. Details of the bench and pilot plant data are presented, together with a discussion of problems encountered. A complete processing flowsheet was designed.
EARL R. PARKER SYMPOSIUM ON STRUCTURE/ PROPERTY RELATIONSHIPS: MICROSTRUCTURE AND MECHANICAL PROPERTIES II: Sponsored by The Mechanical Metallurgy, Structural Materials and Physical Metallurgy Committees ojTMS-AIME Mardi Gras D Monday, March 3,1986 Marriott Hotel 2:00p.m. Session Chairmen: Ray W. Carpenter, Center for Solid State Science, Arizona State University, Tempe, Arizona 85287; V. F. Zackay, Materials and Methods, Inc., 1014 West Road, New Canaan, Connecticut 06841
(2:00 p.m.) FUNDAMENTALS OF ALLOY DESIGN FOR CRACK INITIATION AND GROWTH: R. O. Ritchie, Uni'Versity of California, Berkeley, S. D. Anto1ovich, Georgia Institute of Technology, Atlanta, GA, and W. W. Gerberich, University of Minnesota, Minneapolis, MN. A description of the mechanics, micromechanisms and microstructural factors associated with the development of toughness in engineering materials is presented, and applied to considerations of both crack initiation (i.e., fracture
(3:00 p.m.) MICROSTRUCTURE AND FATIGUE FRACTURE CHARACTERISTICS OF HIGH STRENGTH POWDER METALLURGY ALUMINUM ALLOYS*: R. J. Kar, K. M. Bresnahan and G. V. Scarich, Northrop Corporation, Aircraft Division, Hawthorne, CA 90250.
In this investigation, a microstructural and fractographic examination was carried out on three second-generation high strength powder metallurgy (P/M) aluminum alloys. The microstructures of CW67 (Alcoa proprietary composition), Kaiser (AI-7Zn-2. 3Mg-2Cu-0. 2Zr-O. 2Co-0. ICr) and PM64RL (thermomechanically processed PM64) alloys were characterized in the T7X temper using a combination of optical metallography and TEM/STEM techniques. Fracture examination was carried out on specimens of these alloys tested to failure under constant amplitude (R=O.I) and spectrum fatigue loads (Falstaff and a fighter wing spectrum). It was determined that the macroscopic and microscopic fracture characteristics are strongly controlled by microstructural features, such as the types of dispersoids. strengthening precipitates and grain size. Correlations established to date will be discussed. *Work performed under Northrop Independent Research and Development.
(3:30 p.m.) THE ROLE OF MICROSTRUCTURE ON THE STRESS CORROSION CRACKING BEHAVIOR OF STRUCTURAL MATERIALS IN NUCLEAR POWER PLANT ENVIRONMENTS: R. M. Horn, General Electric Company, San Jose, Calitornia 95235 Structural materials such as austenitic stainless steel and nickel base alloys can be susceptible to intergranular stress corrosion cracking (lGSCC) in high temperature, high purity water environments tound in nuclear power plants. Both wrought and weld metal materials have been susceptible depending on the alloy composition and the microstructure present if the correct environmental conditions exist. The factors that influence susceptibility to crack initiation and crack growth tor these different alloys will be discussed. For austenitic stainless steels, the role ot carbon level and environment on IGSCC will be supported with laboratory results. F or nickel-base materials, the role of both compositiion and impurities, such as phosphorus and sulfur, will be related to test results. Finally, the environmental conditions that will arrest IGSCC will be discussed for both alloy systems.
(4:00 p.m.) GRAIN BOUNDARY SEGFEGATION AND ENVIRONMFNTALLY-INDUCED FRACT11Pf. OF ¥.ATERIALS:* R. H. Jones, Pacific Northwest Laboratory, Richland, WA 99352
Segregation of metalJoid impurities such as S,P.Sb etc. to the grain boundaries of materials can cause hydro~en emhrittlement (HE) and interp:ranular stress corrosion cracking (IGSCC). Intergranulcn subcritical crack growth behavior induced r.~' hydrogen is affected by metalloi ~ segregation. Combined impurity-hydrogen effects tpnd to follow the embrittJing trend for impurity segregation j11 the ahsence of hydrogen. Tn Fe, S is more effective than Sb which is more effective than P. A similar relationship has been demonstrated for Ni. The role of metalloid impurity segregation in IGSCC may differ significantly from HE such that an :impurity which has a small effect in HE can have a large effect in IGSCC. Sulfur and P in Ni are examples where this role reversal is observed. *Research sponsored by the Division of Materials Sciences, U. S. Dept. of Energy under contract DE-AC-76-RLO-1830 with Battelle 'Memorial Institute.
TMS Annual Meeting 27 (4:30 p.m.)
(4:30 p.m.)
MICROSTRUCTURE AND PROPERTIES IN TITANIUM ALLOYS: J. A. Hall. Indus tri al Product Development, Henderson Technica 1Laboratory , Timet, Henderson, NV 89015
POLYANILINE: AN INEXPENSIVE ENVIRONMENT - STABLE CONDUCTING POLYMER, Alan G. MacDiarmid, Dept. of Chemistry, University Pennsylvama, Philadelphld, PA 19104
Microstructural development rl" .... ~- - "hE' proces::. . . ng of titanium alloys is reviewed with cons.l!.leration given to the influence of alloy type and end product needs. The interaction
A form of polyaniline synthesized by chemical or electrochemical oxidative polymerization in aqueous HCl solutions of aniline, C~H<;NH~, (~$0.40/lb) results in a polymer conducting in the- rnetifllic regime (q~5S/cm). It can be produced in the form of a fi 1m (either free-standing or on a metal backing) or as a powder wh i ch can be compressed into pe 11 et s. It appears to be stable indefinitely in laboratory air. It can be converted to an insulator by dilute aqueous base and can be "re-doped" to the highly conducting form by solutions of aqueous acids. The synehesis and chief chemical, electrochemical and electronic propert i es of the mater i a 1 wi 11 be descr i bed.
of deformation processing with the alloy structure gives rise to
limits of total deformation and these are discussed with respect to in-process failures including manifestations of strain localization.
The fin,,1 structure of titanium alloys is shown to
provide a roadmap of its thermomechanical history. The influence of structure on mechanical properties is discussed with emphasis on the important microstructure-property relationships and related process-microstructure relationships. These will be discussed in terms of the superimposed influence of alloy type and composition.
ELECTRICAL PROPERTIES OF ORGANIC MATERIALS II: Sponsored by the ASMIMSD Electrical, Magnetic and Optical Phenomena Committee Monday, March 3,1986 Mardi Gras C 2:00 p.m. Marriott Hotel Session Chairman: W. W. Fuller, Naval Research Laboratory, Code 6634, Washington, DC 20375-5000
ENGINEERING DESIGN IN METALLURGICAL AN MATERIALS ENGINEERING CURRICULA Sponsored by the TMS Education and Professional Affairs Committee Monday, March 3, 1986 Regent 2:00p.m. Marriott Hotel Session Chairman: G. L. Liedl, Chairman, University Materials Council (formerly DEPTH Committee), Department Head and Professor, School of Materials Engineering, Purdue University, West Lafayette, IN 47907
(2:00 p.m.) THEORETIC ASPECTS OF CONDUCTING ORGANICS, Paul Grant, IBM Research Laboratory, K32-281, 5600 Cottle Road, San Jose, CA 95193 (Abstract not available)
(2:30 p.m.) ELECTRICAL PROPERTIES OF METALLIC POLYMERS, Arthur J. Epstein Department of Physics and Chemistry, Ohio State University, Columbus, OH 43210 Metallic polymers such as doped polyacetylene have high conductivity at room temperature and other metal-like properties. However, these materials are not polymeric analogs of common metals. The role of electronic states such as so~itons, polarons, and bipolarons will be reviewed as well as the mechanisms for charge conduction in these materials. Applications of conducting polymers will also be discussed.
Typically, engineering curricula include at least one year of an appropriate combination of mathematics and basic sciences, one year of eng i neeri ng sc i ences, one-ha 1f yea r of eng i neeri ng design, and one-half year of humanities and social sciences. Ideally, these elements provide an integrated educational experience directed toward developing the ability to apply pertinent knowledge to the identification and solution of practical problems in the designated area of engineering specializati on. Des pi te the importance of the eng i neeri ng des i gn component, it is often a weak part of metallurgical and materials engineering curricula, particularly in its integration across the entire curriculum. This session will include detailed discussion of the various forms of engineering design, the integration of design into existing courses, and the nature of some design-oriented courses currently offered at several insti tutions. The following papers will be presented:
(2:00 p.m.)
(3: 00 p.m.) EFFECT OF PRESSURE ON THE ELECTRICAL PROPERTIES OF ION CONDUCTING POLYMERS*, M.C. Wintersgill, J.J. Fontanella, M.K. Smith, Physics Department, U.S. Naval Academy, Annapol1s, MD 21402, and C.G. Andeen, Physics Department, Case Western Reserve University, Cleveland, OH 44106 The results of high pressure complex admittance measurements on ion conducting polymers such as poly(ethylene oxide) and poly (propylene oxide) are described. The data are used to comment on free volume and coofigurational antropy models for transport. Relevant electrical and mechanical relaxation, differential scanning calorimetry, and fourier transform infrared data will also be discussed.
THE ENGINEERING DESIGN COMPONENT OF CURRICULA AND ITS EVALUATION BY ABET: D E. Mikkola, Member EAC/ABET, Professor, Department of Metallurgical Engineering, Michigan Technological University, Houghton, MI 49931
(2:20 p.m.) AN INDUSTRIAL VIEW OF DESIGN IN ENGINEERING EDUCATION: G. H. Geiger, President-elect ABET, Vice President of Technology, North Star Steel Company, 2901 Metro Drive, Bloomington MN 55420
*This work was supported in part by the Office of Naval Research
(3:30 p.m.)
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(2:40 p.m.) INTEGRATION OF ENGINEERING DESIGN INTO AN EXISTING ENGINEERING CURRICULUM: Col. M. A. Paol ino, Professor of t1echanical Engineering, Department of Mechanics, United States Military Academy, West Point, NY 10996
(4:00 p.m.) THE STRUCTURE, PROPERTIES, AND APPLICATIONS OF HIGHLY CONDUCTING CARBON-BASED POLYMERS, R.H. Baughmann, Z. Iqbal, A. Jen, R.L. Elsenbaumer, and L.W. Shacklette, AIl1ed Corportion, Morristown, NJ 07960 We will review recent progress on a range of new conducting po 1ymers - both i nherent.1y cond uct i ng polymers and those th at result from the addition of electron donors and acceptors to insulating polymers. These compositions include solution processible doped polymers and inherently conducting hydrocarbon and non-hydrocarbon po 1ymers h av i ng cova 1ent bond i ng in up to three-dimensions. The relationships between structure and properties, based on theoretical and experimental results, and selected appl ications will provide the focus.
(3 :00 p.m.)
THE SENIOR PROJECT EXPERIENCE AT MICHIGAN TECH: K. B. Rundman, Professor, Department of Metallurgical Engineerinq;--Hlc-hlganTechnological University, Houghton, MI 49931
(3:20 p.m.) ENGINEERING DESIGN IN A CAPSTONE COURSE IN MATERIALS SELECTION AT THE UNIVERSITY OF FLORIDA: E. D. Verink, Jr.,Chairman and Professor, Department of MaterialSScience ari(JEngineering, University of Florida, Gainesville, FL 32611
28 TMS Annual Meeting (3:40 p.llI)
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(3:50 p.m.) PANEL DISCUSSION WITH AUDIENCE PARTICIPATION
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VIRONMENT AL EFFECTS II TMS-AIME General Abstract Session I ay, March 3, 1986 I Mardi Gras A-B , 00 II p.m. I Marriott Hotel Chairman: Neville Moody, P.O. Box 969, Sandia Naional Laboratories, Livermore CA 94550
(3:20 p.m.) THE INFLUENCE OF RUBIDIUN ON STRENGTH AND DUCTILITY OF AUSTENITIC STAINLESS STEELS: P. Trevena and f1.F. NiCholas, Materials Development Division, AERE - Harwell, Didcot, Oxfordshire, OXllORA England; N.S. Stoloff, f·laterials Engineering Dept., Rensselaer Polytechnic Institute, Troy, NY 12180-3590 Liquid rubidium environments are shown to increase the strain hardening rate, ultimate tensile strength and ductility of several austenitic stainless steels, including types 304L, 316 and 321. The effect is most pronounced near the melting point of rubidium (39°C) and decreases as temperature increases. Ductility is enhanced with increasing strain rates in the range 5.5xlO- 5 to 5.5xlO- 2 sec 1 , further suggesting that diffusion is not involved. Metallurgical structure of 304L also is shown to i nfl uence the results. Fractographi c features are unchanged by rubidium; fracture always occurs by microvoid coalescence. Rubidium-enhanced ductility is suggested to arise from an adsorption-induced increase in surface dislocation mobility, leading to increased strain hardening and delayed necking.
(3:40 p.m.) II.
WEAR RESISTANT COATINGS FOR AGRICULTURAL APPLICATIONS by J. L. McAfee, F. J. Worzala, University of Wis., 1509 University Ave., t~adison, WI 53706 and C. d'Angelo, Metallic Bonds, Ltd., Beloit, WI. Blades and tillage tines associated with agricultural and road construction equipment experience rapid wear as a result of the harsh abrasive/corrosive environments encountered in normal operation. While some of these items are currently manufactured with wear resi stant coati ngs, the technologies involved are decades out of date. To this end, a survey of currently ava il able wear resi stant coati ngs was initiated. A variety of coatings were applied to low alloy steel coupons vi a thermal spray, non-trans ferred pl asma arc, and electroless plating techniques. Samples were examined in the as-coated and the heat treated condition. The coated coupons were observed metallographically and subjected to 3 point bend testing. Separate samples were prepared for bond strength evaluation and wear rate comparisons. The results of this evaluation and the characteristics of the most promising coatings will be discussed.
(2:20 p.m.) KINETICS OF NICKEL SULFIllATlON AT 560-600°C: R. Y. Lin, Department of Haterials Science and Metallurgical Engi~leering. M.L. fl12. University of CincinnaU. Cincinnati, OH 45221-0012. The kiTlt'tics of nickel sulfidation at 560-600°C to form Sl-Ni3S2 phase in gas mixtures of H2S and H2 has been studied in our high temperature corrosion laboratory using a thermogravimetric analysis (TBA) apparalus. It has been found that the rate of reaction is a function of not only temperature and sulfur partial pressure, but also tile partial pressure of H2 S. The scale product has been verif ipd throllgh the x-ray diffraction analysis. The SEN examinations n[ the reaction product show that, of the same reaction temperature and sulfur partial pressure, the grain size of the sulfide product un the sample surface is finer with lower PH ,S' A like1y surface reaction mechanism has been proposed to dc:<-;crlbe tile r(:'
(2:40 p.m.) PREDICTING SENSITIZATION IN 304 STAINLESS STEEL WELDS S. Kou, N. A. Zreiba and M. C. Tsai, Department of Metallurgicali!nd Mineral Engineering, University of Wisconsin, Madision, WI 53706. Predicting sensitization in welds of 304 stainless steel is of great interest to both metallurgists and welding engineers. Experimental data on isothermal sensitization of 304 stainless steel were combined with a heat flow computer model. The extent of sensitization was calculated and compared with welds of 304 stainless steel made under various welding conditions.
(3:00 p.m.) EVIDENCE FOR DEFORMATION· INCUCED CLEAVAGE DURING TRANSGRANULAR STRESS CORROSION CRACKING OF o(.-BRASS: M.J. Kaufman. National Bureau of Standards) Gaithersburg, MD 20899; A.J. Forty, University of Wanvick, Coventry CV4 7AL .. England.
Cartridge brass (Cu 30:"',n) salaples were pulled ~g tension using a crosshead extension rate of approximatel~ 10 cm/s in a nontarnishing ammoniacal solution. Typical transgram..:lar stress corrosion fractures were produced which displayed the cbaracteris t ic appearance of quas i - bri t t Ie cleavage. However, closer examination revealed that within certain grains, the crack path was significantl~.different from the usual {OIl} cleavage, i.e. the crack propagated on two {Olll planes which intersected to form a series of ridges and valleys. Furthermore, the cleavage step river patterns in these regions indicated that the crack propagated away from the peaks of the ridges (valleys) and that these ridges had undergone significant plastic deformation indicating that deformation preceded the cleavege process. The various results will be described and discussed in terms of other results concerning environmental degradation of materials.
EROSION MECHANISMS IN DUCTILE METALS: C. T. Morrison, J. L. Routbort* and R. O. Scattergood, North Carolina State University. Raleigh, NC 27695 7907; Argonne National Laboratory, Argonne, IL, 60439.
*
Erosion rate measurements and SEM micrographic observations were made on 304 stainless steel eroded by sharp alumina particles. Both the velocity and particle-size dependence of the erosion rates were independent of the impact angle in the range from 10 to 90 degrees. The SEM observations on steady-state erosion surfaces showed similar features at both low and high impact angles. The results suggest that a single erosion mechanism can be operative at all impact angles in ductile metals like stainless steel. This is in contrast to a two-mechanism approach where a micromachining mechanism controls erosion at lower, oblique angles of impact. Results reported in the literature for other metals tend to confirm the conclusions. but there are certain inconsistencies in the data that may be due to differences in experimental techniques. The physical basis for a single-mechanism approa~h will be discllssed.
(4:00 p.m.) DEVELOPMENT AND EVALUATION OF HIGH- TEMPERATURE/LOW-FRICTION COPPER-GRAPHITE COMPOSITES: K.C. Owen, C. Persad and Z. Eliezer, Center for MS&E, The University of Texas, Austin, TX 78712. Fine copper powder (-325 mesh) has been consolidated with varying concentrations of graphite powder utilizing a high-energy rate method. The result was a series of high-temperature/low-friction composite materials. Differing types, particle sizes, and ratios of graphite were found to produce substantial variations in tribological, mechanical, and electrical properties. Friction and wear tests, hardness, and conductance measurements were used in the evaluation of the copper-graphite specimens. For comparison purposes, pure copper and a conventionally sintered commercial copper-graphite composite were also evaluated. Scanning Electron Microscopy was used to observe wear surfaces and wea r debri s and to defi ne the wea r mechan isms. The nature of the copper-graphite interface was found to significantly influence the tribological, mechanical, and electrical properties of the composite material. This research was supported by DARPA, under NADC contract N6 2269-85-C-0222.
(4:20 p.m.) THE INFLUENCE OF STACK I NG FAULT ENERGY AND DEFORMATI ON- INDUCED RES I DUAL STRESSES IN THE WEAR BEHAVIOR OF ALUMINUM BRONZES: G. Carro and J.J. Wert, Dept. of Materials Science & Engineering Vanderbilt University, Nashville, TN 37235 An essential process occurring during unl ubricated sl iding wear of aluminum bronze is the development and subsequent delamination of a transfer layer. During the delamination process, subsurface cracks develop and propagate parallel to the sliding surface. The presence of a tensile stress perpendicular to the surface should assist the delamination process. A previous study, using the conventional two-exposure X-ray technique, has shown that compressive residual stresses parallel to the surface are developed during sliding wear. The goal of this work was to determine, using the sin 2 i» technique, whether tensi le residual stresses develop in the vicinity of the worn surface (perpendicular to it) of aluminum bronzes of different compositions and stacking fault energies. The results obtained indicate that in fact such stresses are present and that their magnitude increases for increasing wear rates. The authors gratefully acknowledge support from the National Science Foundation through Grant DMR8312241.
(4:40 p.m.) THE EFFECT OF THE PROCESS PARAMETERS ON THE EROSIVITY OF SPUTTERED Ni+TiB2: T.N. McKechnie and J.J. Wert, Department of Mechanical and Materials Engineering, Vanderbilt University, Nashvi 11 e, TN 37235. The erosion resistance of many components can be enhanced thru
the use of coatings. Sputtered Ni+TiB2 coatings were shown in this investigation to dramatically improve the erosion resistance of Ti-6Al-4V and Inconel 718 coupons. The sputtering process parameters and the surface preparation techniques were varied to maximize the erosion resistance of Ni+TiB 2 . The sputtering parameters investigated include deposition rate, bias voltage and' bias. Mechanical grinding and grit blasting parameters were varied to maximize coating adherence. Erosion rates were found to be heavily dependent on the coating microstructure. This investigation determined that a 10% or less nickel, balance TiB2' coating deposited by a multiple pass sputtering operation on a mechanically ground substrate is most resistant to solid particle erosion. The mechanisms of brittle coating fail ure are described. The authors gratefully acknowledge support from the General Electric Company, Evendale, Ohio. (5:00 p.m.) MICROSTRUCTURAL EFFECTS FOR EROSION IN AL-SI ALLOYS:
S. K. Hovis
and R. O. Scattergood*, Sumitomo Electric, Research Triangle Park,
NC 27709; *North Carolina State University, Raleigh, NC 276957907. Erosion rate measurements and micrographic observations were made for a series of AI-Si alloys eroded by sharp alumina particles in order to investigate microstructural effects. When the microstructural scale is large relative to the size of impact events, the erosion rates can be described by a mechanism-independent inverse rule-ai-mixtures averaging law. Measurements on an Al-20 wt.% Si hypereutectic alloy containing large primary Si particles in a eutectic matrix confirmed the inverse rule. When the microstructural scale is small relative to the size of impact events, the averaging law for the microstructure depends on the erosion mechanisms and related microstructural constraints. Measurements on an Al-12 wt.% Si eutectic alloy containing a fine dispersion of Si in Al showed that ductility constraints due to the Si particles modify the erosion mechanisms operative in pure AI.
EXPERIMENT AL METHODS-JOINT SESSION-ON HIGH TEMPERATURE SCIENCE AND MICROGRAVITY MATERIALS SCIENCE RESEARCH II Sponsored by the ASMIMSD Thermodynamic Data Committee Monday, March 3,1986 Mardi Gras F-G 2:00 p.m. Marriott Hotel Chairman: R. A. Schiffman, Midwest Research Institute, Kansas City, Missouri 64110; Session Chair: M. H. Johnston, NASA-Marshall Space Flight Center, Huntsville, Alabama 35812
TMS Annual Meeting 29 time resolution. An apparatus, suit<1blc for the NASA KC-135 f1 ight program, has heen constructed for tbe study of stahi] itv of molten specimens. Initial C'xperiments, performed eluring zero-gravity simulations with the aircraft, show that rod-shaped niobium specimens can be successfully pulse-heated into the liquid phase.
(2:50 p.m.) ENTHALPY MEASUREMENTS ON REFRACTORY METALS BY MEANS OF LEVITATION CALORIMETRY: M. G. Frohberg, Technische Universifat Berl in, Insti tut fur Metallurgie (Allgemeine Metallurgie) The enthalpy of niobium, tantalum, molybdenum and tungsten was measured in the solid and liquid state by use of levitation melting combined with an isoperibol drop calorimeter. Particular attention was paid to the accuracy of optical temperature measurement and the evaluation of heat losses from the sample during the fa 11. From the entha 1 pi es of the refractory meta 1sin the soli d dnd liquid state the heats and entropies of melting were deternined. A comparison is done for those metals were earlier expe)"imental data are available.
(3 :15 p.m.)
CONTAINERLESS STUDY OF HIGH TEMPERATURE REACfIONS BY LASER INDUCED FLUORESCENCE:* P. C. Nordine and R. A. Schiffman, Midwest Research Institute, Kansas City, MO Laser induced fluorescence and laser heating, in combination with aerodynamic (gas jet) and electromagnetic levitation techniques were used to study high temperature reactions. Quantitative measurements of a variety of high temperature properties were achieved on ceramics (alumina, sapphire, LaB6) and metals (molybdenum, tungsten, and liquid alloys). The methods will be discussed and their application illustrated by selected results from completed studies and work in progress. * This work was supported by NASA. (3:40 p.m.)
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(4:00 p.m.) HIGH-SPEED PHOTOGRAPHIC STUOIES OF HIGH TEMPERATURE PHENOMENA:* G. F. Melton, R. G. Behrens, and S. M. Valone, Materials Chemistry Group, Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM. This paper will discuss and present examples of high temperature processes stud i ed with high speed photograph i c techn i ques. In particular, studies of wave front propagation in highly exothermic ceramic and metal/metal oxide chemical systems, studies of ignition and combustion in systems ignited using a high energy HF /DF 1aser, and stud i es of wett i ng and spread i ng of mo Hen titanium on graphite and titanium carbide will be discussed. A NAC high speed camera operating at framing speeds of 400-2000 frames sec l was used in these investigations.
(2:00 p.m.) A NEW LASER AUTOCLAVE TECHNIQUE FOR HIGH TEMPERATURE THERl10PHYSICAL PROPERTY MEASUREMENTS
R.W. Ohse, J.-P. Hiernaut. M. Hoch, J. Magill, and P. Werner Commission of the European Corrnnunities, Joint Research Centre, Karlsruhe Establishment, 0-7500 Karlsruhe, Fed. Rep. of Germany A technique is described in which microspheres are heated by pulsed multibeam laser radiation to temperatures in excess of 5000 K on a millisecond timescale. The sample is heated in an autoclave under high inert gas pressure to avoid evaporation at elevated temperatures. The sol id and 1 iquid spheres are posi tioned by containment-free acoustic levitation independent of electrical and magnetic properties of the sample. Temperature, spectral and total emissivity are determined by a new microsecond six-wavelength pyrometer coupled to a fast recording data acquisition system. The density is determined by high resolution microfocus x-ray shadow technique. The specific heat is determined from the rate of change of the sample temperature in the cooling phase. First results using U0 microspheres will 2 be presented.
(2:25 p.m.) A DYNAMIC METHOD FOR THERMOPHYSICAL MEASUREMENTS IN A MICROGRAVlTY ENVIRONMENT: A. P. Miiller and A. Cezairliyan,
National Bureau of Standards, r,aithersburg, MD. Millisecond-resolution dynamic techniques, when uti! ized on ground, are limited to the solid phase of the specimen since specimens become geometrically unstable during melting and collapse due to the influene'e of gravity. A dynamic method is being developed which, in a microgravity environment, will extend accurate thermophysical measurements on high-melting point electrically-conducting substances to temperatures above their melting point. The basic method involves heating the specimen resistively from room temperature to temperatures of interest in about 1 s by passing an electrical current pulse through it while measuring the pertinent experimental quantities with millisecond
* This work was funded in part by the Defense Advanced Research Projects Agency and in part by NASA Microgravity Sciences through NASA Lewis Research Center.
(4:25 p.m.) MICROGRAVITY POLLUTION AND ITS EFFECT ON MATERIAL SCI ENCE: R. Boudreault, Canadian Astronautics Ltd, Ottawa, Ontario, Canada K2H 8K7 The influence of microgravity perturbation produced by creW' motion, atmospheric drag and thrusters firing on material processing in space is made. A comparison of different orbiting vehicle being considered for MPS is made. The effect of the microgravity "pollution!! on experiments are quantified and a discussion on its effects on eventual commercial activities is presented. Some experimental data and lessons on minimizing this pollution are discussed.
(4:50 p.m.) A HIGH-TEMPERATURE SINGLE PARTICLE THER~10GRAVIMETRIC ANALYZER: R.E. Spjut, Department of Materials Science and Engineering, M.LT., Cambridge, MA 02139. Gas-solid or gas-liquid reactions of single particles in the to 100 mi crometer size range at temperatures from ambi ent to approximately 5000 K can be studied in the ElectrodynamicThermogravimetric Analyzer. A particle is frictionally charged and captured by a dynamic electric field. A feedback control system helps maintain particle position. The particle is weighed either by electron removal or by measurement of the drag coefficient. The particle is heated by a carbon dioxide laser and the temperature is monitored optically. The experimental duration can range from days down to almost a millisecond. Design parameters and technical 1 imitations are presented and representative experimental results are shown.
30 TMS Annual Meeting
BOUNDARIES TMS-AIME General Abstract Session j"IUnuay, March 3,1986 Mardi Gras K 2:00 p.m. Marriott Hotel Session Chairmen: R. H. Wagoner and W. A. T. Clark, Dept. of Metallurgical Engrg., The Ohio State University, 116 W. 19th Avenue, Columbus, OH 43210
using Kikuchi patterns with the aid of a computer program. Interactions between the boundary and the dislocation array were observed and analyzed using the g, boO criterion and weak beam microscopy. The boundary parameters and the dislocation array information obtained using the TEM were used in 1) Force Field calculations to determine the stress acting at the head of the dislocation array, and 2) for comparison with interactions predicted from geometrical model s of interfacial structure. *Sponsored by NSF Research Grant # OMR-8314061
(3: 20 Il.m.)
INSTABILITY OF PLANAR LOW-ANGLE GRAIN BOUNDARIES A.H. King, Dept. of Mat. Sci. &. Eng., State University of New York, Stony Brook, NY I 1794. Low-angle grain boundaries of mixed character (i.e. neither pure twist
nor pure tilt) are readily observable in metals, using transrnission electron microscopy. In all cases where a careful analysis of the dislocation line directions has been performed, it has been fOl,.lnd that such boundaries are not planar, but the dislocations define a "puckered" or facetted boundary plane. These boundaries are still correctly analysable using Boll mann' 50-lattice approach, but the dislocation line directions are not easy to predict: they do not, for example give rise to pure screw or edge dislocation segments. An analysis of the interactions between the various dislocation segments, based upon isotropic elasticity, indicates that this is the cause of the puckering, and good agreement has been obtained between the observed structures and the cmfigurations predicted by the theory. Acknowledgement: This work is supported by the National Science Foundation under grant Ii DMR8216188.
THE MICROMECHANISM OF SLIP PROPAGATION THROUGH " HIGH ANGLE BOUNDARY IN ALPHA BRASS:* Thomas Bamford, Z. Shen, B. Hardiman, W.A.T. Clark, R.H. Wagoner, Dept. of Metallurgical Engineering, The Ohio State University, Columbus, Ohio, 43210. The micromechanfsms, critical stress and geometrical conditions under which dislocations propagate from one crystal to another have been studied by combining TEM observation with quantitative stress analysis. In a static TEM experiment on alpha brass, it was possible to characterize fully the nucleation of a dislocation from a high angle boundary due to the stress at the tip of 'a dislocation pileup. Quantitative stress analysis showed that propagation across the boundary took place onto the slip system with the maximum resolved shear stress, which was 130 MPa. A nucleation mechanism was proposed which indicates that a geometrical factor taking into account the angle formed by slip planes at the boundary may be necessary to reliably predict a propagati on event. *Supported by NSF Grant DMR-81314061
( 3:40 p.m.) (2:20 p.m.) GRAIN BOUNDARY SLIDING IN WIRES WITH BAMBOO STRUCTURE:
*
J. H. Schneibel and G. F. Petersen, Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
High temperature torsion experiments on wires with bamboostructures have been performed. In nickel the transition from non-linear grain boundary sliding at high stresses to newtonian viscous sliding at low stresses coincides with the transition to negligible grain deformation. In a Fe-15% Cr-15% Ni stainless steel, on the other hand, newtonian-viscous sliding could not be verified, even in the absence of significant grain deformation.
This finding suggests that diffusional creep in this steel may become inhibited at small grain sizes.
Additional experiments are
presently being conducted with a nickel-aluminide (NiAl 24 Bo.2). The results are discussed in terms of Raj and Ashby's theory on
diffusional sliding and Reading and Smith's [Phil. Mag. 51A, 71-78 (J 985) 1 IOOdel of non-linear lattice dislocation grain boundary sliding. *Research sgQnliored by the Division of Materials SSietlCeS,
A HIGH RESOLUTION TRANSMISSION ELECTRON MICROSCOPY AND COMPUTER IMAGE SIMULATION STUDY OF STRUCTURE A11/D SEGREGATION IN SILICON GRAIN BOUNDARIES: ULJI.2!lf. and R. Gronsky, Materials and Molecular Researcb Division, Lawrence Berkeley Laboratory B77G Berkeley, CA 94720 High-resolution TEM and image simulation bave been applied to tbe study of silicon grain boundaries. Detailed comparisons of experimentaJ aod calculated images give support to tbe zigzag model of tbe E=9 <110> tilt grain boundary and to a repeat unit consisting of a 45· dislocation pair """",iated with a 45' dislocation dipole for tbe E=13 and E=25 <100> tilt boundaries. In addition, tbe potential application of tbis tecbnique to tbe study of core oegregation bas been evaluated with image simulation. Results indicate that segregated arsenic atomic columos are detectable in lattice ime.ges for linear CODceD~ trations > 20%. Concen trations of -5% may be detected witb diffu8e imaging. Optimum imaging conditions are obtained for a specimen thicknees of half the extinction distance. These contrast features are illustrated with observatioDs 00 a E=9 boundary, containing gold by diffusion.
U.S. Department t Energy under Contract No. DE-ACUS-84 R214UU with Mattin Marietta Energy Systems, Inc.
(4:UU p.m.)
(2:40 p.m.) DISLOCATION PILE-UP AND GRAIN BOUNDARY INTERACTIONS IN TYPE 304 STAINLESS STEEL:* Z. Shen, R. H. Wagoner and W. A. T. Clark, ·Dept. of Metallurgical!iigTneering, The Ohio State University, 116 West 19th Avenue, Columbus, OH 43210 Several dislocation pile-ups at grain boundaries in type 304 stainless steel were observed using the transmission electron microscope (TEM). The pile-up/boundary systems were fully characterized crystallographically and the resulting information used in anisotropic analysis of the elastic stress field resulting from these defects. Predictions of slip propagation mechanisms through the boundary from these calculations and from other proposed geometri c factors were compared wi th observed sl ip systems where pass-through could be identified. Mechanisms for slip transmission will be discussed in terms of these results.
EFFEC T OF SOLUTE ON GRAI N BOUNDARY REHAV I OR OUR I NG 01 GM: T. A. Parthasarathf' Dept. of r-'etallurgy & Mining Engineer:Tng;' OnlVerSlty 0 Illinois at Urbana-Champaign, Urbana, IL 6180l. Different mechanisms have been proposed to explain the observation of Di ffusion Induced Grain boundary Migration (DIGM). These di ffer widely in their predictions of how the type of diffusing solute would affect the behavior of grain houndary during OIGM. Experiments have been conducted to study the effect of cadmium and zinc as diffusing solutes on the OIGM morphology exhibited by copper, under similar conditions. Interesting results thus ohtained will be presented and di scussed.
(4:20 p.m.) IN-SITU STUDY OF MIGRATING 1:5 TILT BOUNDARIES IN GOLD USING TRANSMISSION ELECTRON fIICROSCOPY:* S. E. Babcock and R. W. Balluffi, Department of Materials Science & Eng., Massachusetts Institute
*Supported!5YllS' Grant DMR-81314061
of Technology, Cambridge. MA 02139
(3:00 p.m.) TEM STUDIES OF SLIP PROPAGATION AT HIGH ANGLE GRAIN BOUNDARIES* Cynthia M Wise, Z"Y Shen, W A T Clark, R H Wagoner, Dept of Metallurgical Engin~ering, Ohio State Univ, Columbus, OH 43210
Thin film bicrystal specimens containing curved <001> tilt boundaries of predetermined misorientation were produced. Boundaries near the 1:5 misorientation for which all the intrinsic and extrinsic secondary grain boundary dislocations (SGBDs) were imageable were induced to migrate while under observation by heating in the double-tilting heating holder of a transmission electron microscope. SGBDs which retained their dislocation character and were mobile were directly observed in migrating boundaries. The dyna-
Dislocation arrays near high angle grain boundaries in stainless steel have been systematically studied using the transmission electron microscope in order to investigate the mechanisms of slip propagation across high angle grain boundaries. The slip plane, Burgers vector and line direction, of all dislocations in the boundary and the crystal interiors were determined. The boundary plane and misorientation of the crystals were obtained
mic images were recorded using a video camera recording system. The detailed behavior of secondary grain boundary dislocations in the migrating boundaries was studied and will be discussed. *This work was supported by U.S. Department of Energy grant no. DE-FG02-84ER4 5116.
TMS Annual Meeting 31
(4:40 p.m.)
(3:20 p.m.)
X-RAY r~ICROANALYSIS OF EQUILIBRIUM SEGREGATION IN AN ANTIMUNYDOPEU STAINLESS STEEL:* Edward A. Kenik, Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831.
THERMALMECHANICAL PROCESSING OF CRS/CAP AF2-IDA-6 SUPERALLUY: D.J. Willebrand, Cytemp Specialty Steel, Bridgeville, Pa., 15017; D.F. Gray, Teledyne-CAE, P.O.Box 6971, Toledo, Ohio 43612; and R.J. Shipley, TRW Inc., 23555 Euclid Avenue, Cleveland, 0., 44117
X-ray microanalysis in an AEM is a proven technique for the measurement of solute segregation. Solute can segregate to various microstructural features, such as grain and interphase boundaries, surfaces, stacking faults, dislocations, etc. and can strongly influence material performance. Thoug,h Auger spectroscopy is often employed to study grain boundary segregation, some alloys cannot be fractured intergranularly. X-ray microanalysis provi des an a lternat i ve techni que to measure gra in boundary segregation in such cases, as well as segregation to other defects not accessible to Auger analysis. Experimental results of equilibrium segregation of Sb, Cr, and Ni to boundaries in an austenitic stainless steel containing 0.5 at. % Sb will be presented. (*Research sponsored by the Division of Materials Sciences, U.S. Department of Energy, under contract DE-AC0584UR214UO with ~1artin Marietta Energy Systems, Inc.)
HIGH TEMPERATURE ALLOYS II: Advances in ThermalMechanical Processing of Superalloys Sponsored by the TMS High Temperature Alloys Committee Acadia Monday, March 3,1986 Marriott Hotel 2:00p.m. Session Chairmen: K. A. Green, Allison Gas Turbine Division, Indianapolis, IN 46206; D. L. Anton, United Technologies Research Center, East Hartford, CT 06108
(2:00 p.m.) OPPORTUNITIES, CHALLENGES, AND THREATS TO WROUGHT SUPERALLOYS
The development of advanced materials and their processing methods have traditionally played a key role in the evolution of technology for the aerospace industry. An example of this evolution is the high performance turbine disk technology available for aircraft gas turbine engines. Manufacturing methods have been developed for turbine disk alloys which include the production of commercially rapidly solidified (CRS) powders, consolidation of these powders at atmosphere pressure (CAP), and subsequent thermalmechanical processing operations including hot extrusion, isothermal forging, and heat treatment. The end result of these processing operations includes an attractive combination of mechanical properties in thick section sizes. This processing scenario will be described for the AF2-10A-6 powder metallurgy superalloy. Mechanical properties including elevated temperature tensile, stress rupture, and low cycle fatigue results will be presented ·for thick section size components. (3:40 p.m.) TO P1M OR NOT TO P1M?":
Mi chael E. Casey, Robert N. Jarret t,
~g~o~~hgfK Mi~~;~' c;i8~gra f3~i ~~~~i~~:c N~~t~~~~~s N. ~~n~bO~7~mb
The possibility of turning a high strength P/M alloy into a forgeable cast/wrought alloy was examined. The aim of this program is to produce a high strength, forgeable disk material
~ggafi ~~~ ~~~fe~~tic~ri~dr~~~v~dPfg6~vfh~/~t~~g~;~s~r~0;or~e.
order to shift the )" phase boundary to higher temperatures, thus permi tting hot working to be done at correspondingly higher temperatures. The workability,of the standard material containing 15% Co and modified material containing 10%, 5%, and 0% Co was stUdied. Optical and SEM metallography were used to characterize ~~~o~~~i~~~Io~; ~~~r~~i ~~~s a~da~~~ ~;rEiri~:ssing: after casting, '"This work was supported by the NASA-Lewis Research Center by research grant NAG3-57 under the monitorship of Joseph R. Stephens and Coul son Scheuermann.
(Invited Keynote Address): John K. Tien, Janine C. Borofka, and
Michael
E. Casey I Center for Strategl c Materi als, HKSM, Col um-
bia Univ., New York, NY 10027
Alternating between the conflicting needs of high temperature strength and dynamic reliability, critical superalloy components have historically gone from being cast to wrought but now competi tion between these structures presents opportuni ties, challenges, and threats to the future of wrought superalloy high temperat ure components. Opportuni ti es for cont i nued wrought prosper i ty include the matured P/M technologies, microstructural design advances _ in such superalloys as Inconel 718, and recent sucesses in making high strength cast superalloys workable. Challenges include the demands of fracture mechanics design for very clean metal and improved TMP control to produce coarser and more uniform grain size. Direct threats to wrought products extend beyond the replacement of wrought components by monocrystalline, directionally solidified, and preciSion cast components to the fast developing technology and design accepted use of composite and mul tisegmented turbi ne conf igurations. The authors acknowledge AFOSR, NASA, NSF, and ONR for support of their work.
(2:40 p.m.) DEFORMATION MODELING OF POWDER METALLURGY SUPERALLOYS: W.S. Darden and Dr. C.S. Kortovich, TRW Materials & Manufacturing Technology Center, 23555 Euclid Avenue, Cleveland, Ohio 44117 The increasing demand for the use of stronger, tougher, more difficul t to form materials for aircraft engine appl ications has inspired the development of deformation model ing methods which analytically determine metal flow, workability, and optimum processing parameters. The analytical approach replaces the conventional expensive trial and error methods on production equipment. One such system is an elevated temperature compressive flow stress/workability system which considers working temperature, strain, and strain rate. The use of this system along with the concept of a material's efficiency of power dissipation developed by AFWAL is used as a basis for selection of optimum process conditions. An examination of the system, its capabilities and limitations, and examples of deformation modeling analyses for commercially rapidly solidified (CRS)/consolidated at atmospheric pressure (CAP) alloy Y and CRS/CAP AF2-1DA-6 alloy will be presented. (3:00 p.m.) SUPERPLASTIC DEFORMATION OF AN AS-HIP NICKEL-BASE SUPERALLOY':
T. Lertsirungsun, J.C. Borofka, E.A. Schwartzkopf, and J.K. l1en, Center Jor Strategic Materials, HKSM, Columbia Univ., New York, NY
(4:00 p.m.) COMPUT~F
;jDTllLh':'ION CY ISOTHEHMAL AIm HOT DIE ?ORGING: and H. E. Delp;ado ~ W:\'111an-Gordon Compa:1:/ , r,:A ~J153f
ic':-::S~~~"-
lsothermal and 1'10:'':' die fo:re;in£ of high temrerature allo;,/s involve 0xpensive process develupr!1C'nt, die materials and equipment. Often inC'l'J.ced in the process development is or.e or more die tryouts or development runs to verify that the desired metal flm."., properties and die fill are acl:ieved or to find out tLat the cesit:;n must be modified. Sir.1Ulation of the metal flow on a computC'r can yield data on stYains, strain rates, stresses and t emperaLllres in the forging througbout the p:!:'ocess and can rotenti ~ly eliminate t:le need ;"or the development ruYl. ;; ?-D FD1-based rieid viscopla;3tic code called ALFID h8s been used to s:imulate the £'orging 0: a number 0= axisymmetric :~orginfs of superalloys suc~ 8S 718 and ?C'ne 95 and titanium alloys ,mc}] 'Ii-17 and 'Ii fl-2-l.1-2. flome o:~ tl:c results of tbese analyses will be presented alonE "rit}; discussion 0:' tlw code, design optimization, development of C'mrirical constitutive equatlons ar.3 predictio:1 of microstrl~ctures 8nd properties.
(4:20 p.m.) COMPUTER AIDED MANUFACTURE OF SUPERALLOY FORGING BI J. R. Wood, Special Metals Corp., New Hartford, NY
LLET: 13413
A computer control led double manipulator open-die press forging system is being utilized for the manufacture of superalloy forging bi J Jets. The manipulators and press are fuJ ly integrated to provide programmed and automatic forging of round, square, rectangular, or octagon shaped bi llet. Computer aided forging results in greater productivity, improved surface qual ity, closer dimensional control, and structural uniformity. Software programs have been developed to calculate optimum forging schedules based on material properties, press force, handling times, forging temperatures, and bi !let shape. Pertinent process data such as press force, number of passes, on-die/offdie temperatures and times, and finish dimensions are stored by the computer and printed out as required for metallurgical process control. This data is used to further refine and develop new and improved forging techniques.
10027
In this study, the superplastic deformation regime of an as-HIP nickel-base superalloy was mapped at temperatures from 900 C to 1100 C using stepped true strain rate tensile tests. The material tested was obtained from several sources and was HIP consolidated at differel1.t_ conditions. All material was characterized by grain stze, prior particle boundary (PPS) morphology, and PPS chemistry using SEM and EDS. The effect of starting powder stock and HIP consolidation parameters on superplastic deformation and deformed microstructure was revealed. The stepped strain rate technique was also examined in terms of prior strain effects on strain rate sensi ti vi ty. The results of the testing are discussed with respect to HIP processing and forging practice. *This work' was supported by the Air Force under contract AFOSR82-0352A2 monitored by Alan Rosenstein and Ivan F. Caplan.
(4:40 p.m.) DYNAMIC CONSOLIDATION OF NICKEL BASED SUPERALLOY POWDERS: ~
Thadhani, Andrew Mutz, Thad Vreeland,Jr., and Thomas Ahrens, Ca 1 ifornia lnsti tute of Techno logy, Pasadena, Cal i fornia 91125. Shock consolidated nickel based superalloy (pyromet 718 and Rene 95) powders reveal unique microstructures within plastically deformed particle interiors and at melted and resolidified interparticle boundaries. Flyer plate impact experiments, with velocities between 1-1.2 km/s, were used for the shock consolidation of
32 TMS Annual Meeting
(4:00 p.m.)
rs close to solid uensities. Plastic llC'rorm~ltion of )i0\<",kr icles during compaction gives rise to structural that manifested by deformation twinning and fo}'m:ltioJl of l::-loc~\ ion cells and tangles. The inhomogeneous nature of shoel deformation also results in the localization of pLlsti.c str~lin along :1uiahat ic shear bands wi thin powder part iell' i nt eriars. These bands arc extremely narrow (.005-.01 11m wide) and span across several grain lengths (_0.6 lJffi diameter). The micro shear banos reveal a defect substructure characteristic of deformation bands. A fine microcrystalline grain structure is observed at interparticle boundaries. The stability of these structureS at different annealing temperatures will be discussed.
REACTOR
DESIGN
SUPf:KCKITlCAL FLUIIl EXTRACTION APPARATlIS POR Tm: MINERAL PROCESS[NG LABORATORY: ~~~_~c!'Ll~, P. B. Altringer, and n. C. Seine1, 729 Arapeen Drive, Salt Lake City Research Center, BureA.l1 of Nines, Salt Lake City, UT 84108
&
Sponsored by TMS-AIME Hydrometallurgy, Physical Chemistry, and Electrolytic Processes, and SME-AIME Chemical Processing Committees Monday, March 3, 1986 La Galerie 6 2:00 p.m. Marriott Hotel Session Chairpersons: Rolf Wesely, Utah International, Sunnyvale, California; K. H. Han, Department of Metallurgical Engineering, South Dakota School of Mines and Technology, Rapid City, South Dakota 55701
(2:00 p.m.) A STATISTICAL APPROACH TO MULTI-PATRICLE SYSTEM KINETICS: Patrick R. Taylor, University of Idaho, Moscow, Idaho.
A statistical approach to the characterization of kinetics for multi-particle systems is given. The models are based solely upon statistics and probability and the resultant equations are identical to those obtained from the population balance approach. Examples from leaching kinetics are used to illustrate the method s.
(2:30 p.m.)
Supercritical fluids are being tested extenSively as solvents to selectively extract valuahle components from complex matrices. Practical systems usually operate at temperatures of ambient to a few hundred degrees and pressures of 1,000 psig or more. Common sllpercritical fluids are inert, cheap, and nontoxic. 1.aboratory apparatus for research on the extraction of miner;:{ls and related materials with supercritical solvents can he difficult to assemble and operate smoothly. Equipment that has been designed and operated by the Bureau of Mines to allow processing of both liquid and solid samples is described. f)perational examples and extraction data are presented to indicate areas where supercritical solvent extraction could benefit mineral processing.
(4:30 p.m.)
REA;;TOR .JES1GN FOR AGLLCCS-SOl 1D REA:::nONS: Patrick R. Taylor, Lniversity of Idaho, HoscO\v, Idah-o--A review of the fundamentals of reactor design for aqueous-solid reactions is given. Various types of reactors are discussed and examples of current modeling methods are presented. Two examples are used to illustrate the reactor design concepts: activated carbon adsorption in multiple colt:mns and multi-particle leaching in continuous agitated reactors.
INNOVATIONS AND PRODUCTIVITY INCREASE IN NON-FERROUS PYROMET ALLURGICAL PLANTS II Sponsored by the TMS Pyrometallurgical Committee Monday, March 3, 1986 La Galerie 2 2:00 p.m. Marriott Hotel Session Chairmen: H. Asao, Superintendent, Research & Development, Onahama Smelting and Refining Company, Ltd., I-I Nagisa, Onahama, Iwaki-City, Fukushima-Pre., Japan; Richard J. McClincy, Anaconda Minerals Company, Research Department, P.O. Box 27007, Tucson, AZ
LEACHING KINETICS OP MANGANESE ORES WITH AQUEOUS S02: ~ Pahlman, and S. E. Khalafalla, Bureau of Mines, Twin Cities Research Center, ~6Z9 Minnehaha Ave. South, Minne~polls, MN
55417 The Bureau of Mines has conducted column leaching tests on domestic manganese ores to determine the feasibility of extracting manganese from the ores hy In-situ or heap leaching wi th aqueous SOZ solutloTls. Aqueous SOZ was found to be effec tive for leaching manganese as greater than <)0 percent extrl'lctions were obtained. The rate of leaching was found to be dependent upon the rate at which the leach solution can penetrate the are, since the solubilization o'f manganese upon contact w:f.th S02 was observed to be ra~1f' DeEgite low water permeabilities of the ores (as low as 10 to 10 Darcys), the manganese content of larger pieces tested as completely extracted. It appears, therefore, that leaching of manganese opens up the pores, thereby allowing penetration of the leach solution into the are pieces. The results .
(3:00 p.m.)
BREAK
(3:30 p.m.) LIQUID VELOCITIES IN AIR AGITATEO TANKS (PACHUCA TANKS); R. Shekhar and J. W. Evans, Dept. Materials Science and Mineral Englneenng, Univ. of California, Berkeley, CA 94720. Air agitated vessels e.y. Pachuca tanks are frequently encountered in hydrometallurgical operations. A survey of such tanks (carried out by others) has indicated wide divergence in basic design parameters (height to diameter ratio,
(2:00 p.m.) RETROFITTING HAYOEN PLANT TO FLASH SMELTING: W. D. Marczeski, Assistant Superintendent, T. L. Aldrich, Asarco Inc. Hayden, AZ The retrofit called for an INCO-design-flash furnace, a doublecontact acid plant, a gaseous oxygen plant, and a water treatment facility. A consent decree was negotiated between limits for the future operation as well construction and operation. By April longer be able to operate reverberatory
Asarco and EPA to establ ish as setting a time table for 1984, Asarco would no furnaces or roasters.
1,
The project started in January of 1980 with the engineering phase, and ended in November 1983 with start-up of the flash furnace. Extens i ve tra i ni ng of operators and ma i ntenance personne 1 was required due to the use of computers and sophisticated control equipment. Energy conservation was major concern during the engineering phase. The company was willing to spend DLR 1,244 to save a kilowatt hour. The report wi 11 conta i n operati ng experi ence and changes requi red during the first year and a half.
(2:25 p.m.) PRODUCTIVITY IMPROVEMENTS AT INCO'S COPPER CLIFF SMELTER COMPLEX: T.N.Antonioni, J.A. Blanco, C.A. Landolt, and C.M. Mitchell, Inca Limited, Copper Cliff, Ontario, Canada
Starting in the mid-70'S and, particularly in the last three to four years, Inca has implemented major productivity programs with the purpose of decreasing unit costs. Key activities at the Smelter Complex have dealt with improvements in operating and maintenance practices, employee involvement, process control, streamlining of equipment and energy conservation. This paper discusses factors affecting productivity, i.e. specific processing rates per unit. rilte limi ting steps such as equipment deSign and avai labili ty, plant logistics, employee acceptance of changes. process
control, effect of reverts and recycles, etc. Examples of productivity oriented programs are discussed in some detail, including process metallurgy, monitoring and control, equipment performance and plant environment. As a result of these programs, the Smelter Complex has made very significant gains in process productivity and in energy conservation. Specific results for recent years are included and discussed.
(2:50 p.m.) DEVELOPt1ENT OF THE ISAMELT LEAD SMELTING PROCESS: W. J. Errington, f1cKean and Player, Mount Isa Mines Ltd., Dueensland, Austral ia; and W. F. Denholm and Robillard, CSIRO Division of Mineral Enqineerinq, Clayton, Australia The isamelt lead smelting process is a joint mount Isa mines limited and Sciro development based on the use of the patented 15irosmelt" lance. The process is an air based, two stage process. In the first stage, lead sulphide concentrates are added directly to a molten slag bath and fully oxidized by means of air injected into the melt via a submerged 1a nce. The product from stage 1 is a slag rich in lead oxide which is transferred to a second furnace for slag reduction to form lead bullion and discard slag. The process utilizes simple, cheap, readily available reaction vessels, requires minimal feed preparation and uses coal as fuel and reductant. Promising results on a 0.12 tph pilot plant scale resulted in the decision to proceed to a 5 tph demonstration plant. Stage 1 of the plant (oxidation smelting only) was commissioned at mount Isa in September 1983. The high lead slag product from this plant has been used as a partial replacement for recycle sinter in the sinter plant and has thus effectively increased the capacity of the lead smelter. A second furnace was commissioned in August 1985 to allow demonstration of the complete two stage process. The paper describes the development of the process from laboratory crucible testwork to the 5 oph scale plant and discusses the preliminary results from the two stage demonstration plant.
TMS Annual Meeting 33
(4:05 p.m.) LIMITS OF OPERATION AND METHODS OF CONTROL FOR BLAST FURNACES IN NON-FERROUS METALLURGY: B. Madelin and A.
Sevagen, Minemet Recherche The Imetal group operates or used to operate different shaft fUrnaces for lead, nickel matte, cupolas and a zinc imperial smelting furnace (ISF). Various types of blast furnaces were analysed according to three criteria: thermal exchange, chemical exchange, and dynamic flow. Limits of operation of the different furnaces are discussed in the paper and then applied to develop an economically optimized operation (productivity, energy consumption). Key methods of control are presented and discussed: i.e. the top gas temperature (Cupola), the top gas analysis (ISF and iron blast furnace), and wind combustion and distribution (lead blast furnace).
(4:30 p.m.) TREAn1ENT OF VARIOUS SOZ-BEARING GASES FOR. THE PRODUCTION OF SULPHURIC ACID, LIQUID SULPHUR DIOXIDE AND ELEMENTAL SULPHUR; R. Malmstrom, Dr., R. M. Metalconsulting KY, Helsingfors, Finland, and S. A. Petersson, Dr., Boliden Metall AB, Skelleftehamn, Sweden For the removal of sulphur dioxide from smelter gases before the outlet in the atmosphere sulphuric acid is normally produced. Acid production requires relative constant gas flows, comparative small gas volumes with high contents of S02' carefully cleaned gases a. o. The alternatives for the removal of sulphur dioxide are production of liquid sulphur dioxide, elemental sulphur or disposed as sulphite or sulphate. A system is described for a flexible way to handle sulphur dioxide containing process gases. The total gas volume or a part of it is treated in an absorption circuit for removal of sulphur dioxide. After stripping a pure S02-gas or liquid S02 is produced. The produced sulphur dioxide itself can be marketed but can also be used as raw material for production of sulphuric acid and elemental sulphur. Opposed to sulphuric acid the production of liquid sulphur dioxide is not sensitive for variations of gas volumes or the gas content of sulphur dioxide. The system is therefore very suitable and flexible for practical all kinds of S02-bearing process gases. The converting of liquid 502 to sulphuric acid and to elemental sulphur is described.
(3: 15 p.m.)
ON-LINE ANALYSIS OF AIR PARTICULATES IN MOUNT ISA tnNES' LTD. LEAD SMELTER: J. Brown, G. D. Brownlie, D. L. Dekker. and W. J. Smith, Mount Isa Mines Limited, Oueensland, Australia
MICROSTRUCTURE AND PROPERTIES I
A plant wide system for on-line monitoring of airborne dusts and
fumes has been introduced at the mount Isa mines' limited lead sme lter. The sys tem is based on a network of fi ve AMDEL/MIM air particulate monitors which are connected via a common data acquisition link to the lead smelter process control computer system. Each monitor provides an hourly measurement of ambient lead in air, expressed directly in micrograms per cubic metre, and results from all monitors are collated by computer and presented to plant operators for use in locating and quantifying fugitive dust emissions. Details of the monitor design and sinter plant blast furnace application are discussed. The extension of the technique to determine ambient concentrations of other elements is discussed.
TMS-AIME General Abstract Session Mardi Gras H
Monday, March 3,1985 2:00 p.m.
Marriott Hotel
Session Chairman: C. S. Pan de, Code 6320, Naval Research Laboratory, Washington, DC 20375
(2:00 p.m.) (3:40 p.m.) ENERGY OPTIMIZATION IN FLASH SMELTING: Eric H. Partelpoeg, Technical Services Department Head, Hidalqo Smelter, Phelps Dodge Corporation; and W. G. Davenport, Professor, University of Ari zona. The copper smelting industry has been replacing old reverberatory furnaces with energy-efficiency furnaces. While tghis in itself has been a significant move towards reduced energy costs, there is yet no industry consensus as to which mode of flash smelting is optimum. It is possible to model copper smelting, the ensuing converting step, and acid production with linear equations and inequalities. These equations include mass and heat balances, and energy and cost equations. the matrix of equations and inequalities can be entered into a 1 inear programming routine to determine minimum costs.
Such a model has been developed and the results indicate that minimum energy costs are achieved with the following operating parameters. 1) 2)
The grade of matte is 65 % Cu The flash furnace operates autogenously with no air preheat. The flash furnace air is oxygen enriched to approximately 40 vo 1ume % 02.
PROPERTY AND MICROSTRUCTURE CHARACTERIZATIONS FOR THE NOVEL 1M AI-Li-Mg-Cu-Zr ALLOY SYSTEM: D. J. Chell man and R. A. Rainen, Lockheed-California Co., Burbank, CA 91520 and A.P. Divecha and R. K. Garrett, Jr., Naval Surface Weapons Center, Silver Spring, MD 20910 Current research on 1M Al-Li-X alloys has been generally centered on the addition of intermediate Cu and low Mg solute levels to obtain optimum property combinations. The present cooperative stqdy between Lockheed and NSWC represents a departure from these alloy systems, by examining the quaternary alloy of nominal composition AI-2 Li-3 Mg-l Cu-O.14 Zr. Seven ingot metallurgy alloy variants were prepared by chill casting, homogenization, and extrusion to rectangular bar. A screening evaluation on the alloy extrusions was conducted by selected physical and mechanical property tests that incltrled chemistry, density, elastic modulus, hardness, conductivity, tensile, and fracture toughness. Aging responses as a function of temperature, time, and cold work were studied initially in order to identify candidate heat treatment conditions. Tensile elongation and fracture toughness exceeded target goals typ~ cal of conventional 2XXX Al alloys, with values of 8.0 pet. and 30.0 Ksi - in. ~, respectively. An improvement in the strength-toughness property combination was attributed to the optimization of Mg/Cu solute levels for a given Li addition. Optical metallography and SEM observations were documented with respect to solute content and aging treatment.
(2:20 p.m.) MICROSTRUCTURE CHARACTERIZATION OF FERROMAGNETIC MATERIALS USING MAGNETIC NDE METHODS:*
R. Ranjan, O. Buck and R.B. Thompson, Ames
Laboratory-USDOE, Iowa State University, Ames, IA.
The general model employed to obtain these optimum conditions can be modified to represent unique smelting conditions. When this is done to represent the Kennecott-Outokumpu sol id matte converting concept, the resul tant energy costs indicate that the concept of "flash converting" may be a viable alternative to Peirce-Smith converters.
Irreversible magnetic effects can be used for nondestructive characterization of the microstructure of ferromagnetic materials. Discontinuous motion of domain walls in ferromagnetic materials generates bursts of magnetic induction (magnetic Barkhausen noise) and bursts of acoustic emission (acoustic Barkhausen noise) during
i~ation.
These noises in conjunction with the magnetic s (B-H) curve may be used to study the different microphenomena taking place during magnetization. The paper our observations of systematic variations of magnetic and Barkhausen noises and the magnetic hysteresis curves in armed polycrystalline nickel at different stages of annealing different extents of deformations. The results will be disin terms of the activities of 180 0 and non-180° type domain nd their interaction with different crystalline defects. was supported by USDOE, Office of Basic Energy Sciences J of Materials Sciences J under cant ract No. W-74-5-Eng-82.
1M alloy. The cavities in the PM alloy were of spherical shape whereas, in the 1M alloy, they were elongated. Cavity growth in both alloys was found to be dominated by a plasticity controlled hole growth mechanism. The cavitation study has further shown that voids in both alloys pre-existed prior to superplastic deformation. Research supported by NSF and Lockheed Indep. Research.and Dev.
(4:00 p.m.) PRECIPITATION KINETIC STUDIES OF EPSILON COPPER IN HSLA (A7lG) STEEL: L.E. Richards, M.A. Imam, and C.S. Pande, Naval Research Laboratory, Washington, DC 20375-5000
EVOLUTION IN LASER CLAD Fe-Cr-Mn-C ALLOY: J. and J. Mazumder, Dept. of Mechanical and Industrial neering, University of Illinois, Urbana, IL 61801. itu Fe-Cr-Mn-C alloy has been developed 'by laser cladding of I 1016 steel with mixed powder feed. Initial wear data ibited far superior live contact wear resistance when compared h Stellite 6. Optical, SEM and STEM microanalysis techniques employed to characterize the different phases produced rafine microstructure. Microstructural studtes showed a high ree of grain refinement and increased solid solubility of alloying elements which, in turn, produced a fine and uniform distribution of complex types of carbide precipitates and metastable phases in the ferrite matrix because of the high cooling rate. The complex carbides have been identified as M6C and M7 C3 type carbide precipitate and metastable phases are rlch in Cr wlth a small volume fraction of Fe in them. The possible phase transformation sequence was proposed which occurred during liquid-to-solid and solid-solid state transformation: L +L + 6 + (0 + "6C + x) + L + (0 + 11 C + x)1 + (a + "7C3)1I' S *ThlS work was made poss161e by a grant from Quantum Laser Corporation.
(3:00 p.m.) INSITW Ni-Cr-Al-Fe-Hf ALLOY BY LASER CLADDING WITH MIXED POWDER FEED: J. Singh, M. Zmuda and J. Mazumder. Dept. of Mechanical and Industrial Engineering, University of Illinois, Urbana, IL 61801. . There is a significant interest in Ni-Cr-Al-Hf alloy as surface coating for high temperature oxidation resistance. Rare earths such as Hf and Yare major contributors to oxidation resistance since they preferentially oxidize and also those oxides creates "mechani ca 1 peg" effects. In this paper Insitu alloys with high Hf contents are made. Laser cladding with mixed powder feed containing Ni, Cr, Al and Hf was carried out on AISI 1016 steel substrates. A 10 KW CW CO 2 laser with HMo! spatial distribution was used for the cladding. Inherent rapid heating and cooling in laser processing produced ultrafine microstructure with extended solution in the laser cladded region. Uniform distribution of Hf up to 13% in the laser cladded region was produced. The present paper deals with the microstructural development during laser cladding. A brief description of the high temperature oxidation resistance and the industrial applications of the alloy is also included. *This work is supported by AFOSR Materials Science Division.
(3:20 p.m.) THERMAL STABILITY OF RAPIDLY SOLIDIFIED Al-8Fe-2Mo:
J.E. Allison, W.T. Donlon, R.C. Ku and H.K. Plummer, Research. Staff, Ford Motor Company, Dearborn, MI 48121 The influence of thermal exposure on the microstructure and mechanical properties of consolidated, rapidly solidified Al-8F'e-2Mo is being investigated. Hardness measurements indicate that at 315°C, Al-8Fe-2Mo is "stable" to times in excess of 1000 hours and at 375°C it is "stable" to 400 hours at which point the hardness begins to decrease. The influence of such thermal exposures on mechan ieal behav ior wi 11 be di scussed. The mi crostructure of this alloy has been characterized using TEM and energy dispersive microanalysis. The as-extruded microstructure consists of coarse A16Fe dispersoids, aluminum grains approximately 1-5).lffi in diameter and fine dispersoids, usually associated with the aluminum grains. These fine dispersoids consist of needle shaped Al13Fe4 particles, small «50nm) spherical particles of A16Fe and several Al-Mo phases. The evolution of these microstructures after thermal exposure will be described.
(3:40 p.m.) CAVITATION STUDY IN INGOT AND POWDER METALLURGICALLY PROCESSED SUPERPLASTIC Al-L i ALLOYS: *M. C. Pandey, J. Wadsworth+ and A. K. Mukherjee, Department of Mechanical Engineering, Univ. Of California, CA gS616: +Lockheed Palo Alto Research Laboratory, 3251 ijanover St., Palo Alto, CA 94304 Aluminum-lithium alloys, manufactured by both ingot (1M) and rapid solidification powder (PM) metallurgy processes, have been studied for their cavitati8n behavio:r, a\ 450'C, in the strain rate range from 2x10to 10s-. The volume fraction of cavities in the 1M alloy was found, at all strains, to be lower than that in the PM alloy. The size of cavities in the PM alloy, however, was found to be smaller than that in the
The precipitation kinetics of epsilon copper precipitates in commercial HSLA steel (A7l0) and a model low carbon steel has been c haracteri zed by t ransmi s s i on elect ron mi c roscopy (TEM, small angle neutron scattering (SANS), and by hardness measurements. Copper precipitates are coherent with matrix below a certa.in size, but become incoherent after growth. Incoherent precipitates were found to be aligned roughly along <110> direction. When coherent, they are not visible by TEM, but a combination of TEM and SANS techniques has been successfully used to obtain morphology, size distribution and volume fraction of the precipitates.
(4:20 p.m.) THE INDENTATION HARDNESS OF ION IMPLANTED MATERIALS'
R. J. Bourcier, C. M. Stone and A. D. Romig, Jr., Sandia National Laboratories ;-Albuquerque. NM 87185 A study of the microindentation hardness of ion implanted metal surfaces has been performed. A finite element simulation of the indentation test has beer. performed using Ii terature data for 304 stainless steel and a variety of bulk amorphous materials. The model predicts differences in indentation load-depth response attributable to an amorphous ion implanted surface layer, with the implanted material showing a softer response than the unmodified bul k mater i al . Based on these resul ts, an ul tra fine hardness tester has been built to allow ir.dentation testing at loads less than 10 grams and penetration depths less than 1 micrometer using a Vickers pyramid indenter (-0.5 micrometer radius). Tests performed' usi ng thi s machi ne show good agreement wi th the f ini te element predictions. These results will be discussed with regards to the mechanical properties of ion implanted surfaces and their possible implications for the wear of implanted surfaces. *This work performed at Sandia National Laboratories supported by the u.S. DOE under contract number DE-AC04-76DP00789.
(4:40 p.m.) THE INFLUENCE OF ELEVATED TEMPERATURE ON THE STRUCTURE AND PROPERTIES OF Ti-6Al-2Sn-4Zr-2Mo-0.08Si, W-S. Cho*, W.T. Donlon*~ J.W. Jones* and J.E. Allison**; *Department of Metallurgy and Materials Science, University of Michigan, Ann Arbor, MI 48109 and **Research Staff, Ford Motor Company, Dearborn, MI, 48121. Microstructural stability, tensile and creep properties have been investigated in Ti-6Al-2Sn-4Zr-2Mo-0.08Si at 650°C and 760°C. Microstructural changes have been documented via TEM, microanalysis and room temperature hardness measurements. At 760°C, the degeneration of 8-platelets leads to a decrease in hardness up to times of about 100 hours at which point strengthening due to precipitation of silicides leads to increasing hardness. The level of this hardness increase depends on the details of the solution treatment. However, in general, the hardness after 300 hours is very near that of the unexposed condition. Similar results at 650°C will also be presented. The influence of this microstructural degra'dation on creep behavior at 650°C and 760°C wi 11 be descri bed.
(5:00 p.m.) THE EFFECT OF AGING TREATMENTS ON THE MICROSTRUCTURE AND THE FRACTURE PATH IN A Cr-Mn-N AUSTENITIC STAINLeSS STEEL: S.J. Lee and K.M. Ralls, Dept. of Mech. Eng., Center for MS&E,l'lie Diilversity of Texas, Austin, Texas 78712 The microstructural changes in a Cr-Mn-N austenitic stainless steel have been observed following aging treatments carried out at temperatures from 500 to 800°C for times varying from Precipitates, particularly along the grain 4 h to 1000 h. bounda ri es, have been s tudi ed by opt i ca 1 mi c roscopy, and by SEM and TEM analysis. Precipitation of phases on aging begins preferentially .in the boundaries of grains and twins. The discontinuous grain boundary precipitate is resolved as a "pearlitic" lamellar precipitate and its chemical composition has been determined with a Ni-C double stage extraction replica by the use of STEM together with EDX microanalysis. Chromium depl et i on adjacent to gra i n boundary preci pitates is observed in an i ntergranul arly-fractured surface through Auger electron spectroscopy.
(3:50 p.m.)
MODELING IN PROCESS METALLURGY I: FLUID FLOW PHENOMENA Sponsored by the TMS Physical Chemistry Committee and the PTDI/SS Monday, March 3,1986 Mardi Gras N 2:00p.m. Marriott Hotel Session Chairmen: J. Szekely, Dept. of Materials Science and Engr., Massachusetts Institute of Technology, Cambridge, MA 02139; R. A. Stoehr, Dept. of Metallurgical and Materials Engineering, University of Pittsburgh, Pittsburgh, PA 15261
TMS Annual Meeting 35
The Modelling of Transient Melting and Solidification in Weldpools J. Szekely, G. Oreper and T. W. Eagar, Department of Materials Science and Engineering. Massachusetts Institute of Technology, Cambridge, MA 02139 A Mathematical statement is developed of the factors that govern the growth and collapse of weldpools in spot welding operations. In the model allowance is made for the role played by convection, as driven by elec tromagnet ic, buoyancy and su rf ace tension forces. Computed results are given describing the behavior of steel, titanium and aluminum. The analytical asymptotic expressions allow one to draw some general conclusions regarding the behavior of these systems.
(4: 15 p.m.) FLOW BEHAVIOR DURING MIXING BY GAS AND GAS-PAHTlCLE INJECTlON. Chiao Y.W. Chang. M.J. McNaHan. Department of ciV11 T.W.
Engineering. Mechanics. and Metallurgy. University of Illinois at Chicago. P.O. Box 4348. ChHago. IL 60680.
(2:00 p.m.) A General Computational Scheme for Predicting the al Velocity and Temperature Fields in Tundishes: and N. EI-Kaddah, Department of Materials Science Massachusetts Institute of Technology, Cambridge,
Three DimensionJ. Szekely,
and Engineering, MA 02139
Through the statement of the three dimensional turbulent Navier-Stokes equations and the corresponding differential thermal energy balance equation a general representation has been developed to describe the velocity field, the temperature field and the maps of the turbulent kinetic energy in tundishes. This treatment enables one to allow for the role played by weirs and gates in modifying the flow; furthermore both heat losses and the role of buoyancy driven flow are also discussed, together with their implications regarding optimal tundish design.
(2:25 p.m.) MODELING OF FLUID FLOW AND MIXING IN CONTINUOUS CASTING TUNDISHES: Youduo He and Yogeshwar Sahai, Dept. of Metallurgical Engineering, The Ohio State UnlVerslty, 116 West 19th Avenue, Columbus, Ohio 43210. A mathematical model to represent turbulent fluid flow and mix-
ing in continuous casting tundishes will be presented. The model involves solution of the three dimensional turbulent NavierStokes equation, turbulence being modelled by the so called K-E, two equation model. The influence of various physical flow control devices, such as dams and weirs on the fluid flow and associated mixing has been studied. The theoretical predictions are compared with measurements obtained in water models. The relevance of these results in industrial practice will be discussed. (2:50 p.m.) MODELING TRANSIENT FLOW IN TUNDISHES:
R.A. Stoehr, Dept. of
Gas and gas-particle jets are often used to m1X ladles of l1quid metal after alloy adClitions. When reactive adaitions are made. the recovery of the alloy is afr'ected by the immediate trajectory of the adClition. with trajectories whl.ch br1ng unmixed alloy into the vlcini ty of tne slag layer llkely to produce lower recoveries. The time required to disperse tne addition is afl"ected by tne mlXing power density ana may be affected by other operating parameters. The trajectory of tne alloy adai tion is afI"ected primarily by operating parameters such as the location of the alloy adai tion. A water model of a ladle is used to investigate the effects of changes in tne position. loading. and orientation of the lance on tne trajectory of the tracer and the time required to completely m1X the ladle.
(4:40 p.m.) MI XI NG AND MASS TRANSFER PHENOMENA IN BOTTOM- INJECTED REACTORS: Tadeusz Stapurewicz, Henry Krumb School of Columbia UniverSIty, New York, NY' 10027, Nickolas J. Henry Krumb School of Mines, Columbia University, New 10027
GAS-LI QU ID Mi nes, Themelis, York, NY
Experimental measurements of mixing time and mass transfer coefficients were undertaken in a trasparent aqueous model. The purpose of the work was to determine the effect of a bottom-injected gas jet, at di fferent flowrates and for various porous plug and orifice injectors, on the mixing intensity and gas-liquid mass transfer in the bath. The measurements of mixing time were compared with calculations based on the Sahai-Guthrie model describing the velocity field in such systems. The effect of injection conditions on the rate of mass transfer between a carbon dioxide jet and an aqueous solution of sodium hydroxide was investigated in the same model. An attempt was made to compare the measured mass transfer coefficients with the Frossling correlation for mass transfer to spherical particles. Generally, there was a good agreement between the experimental results and the theoretical predictions.
Metallurgical and Materials Engineering, University of Pittsburgh, Pittsburgh, PA
15261
Tundishes are designed to smooth metal flow to casters and to provide for separation of inclusions from the metal during traflSfer. Physical and mathematical modeling has previously provicled a great deal of information on which to base their desi~. including the location of dams and weirs, to accomplish these purposes. The mathematical model in;:; has, heretofore, dealt \:it'h quasi-steady state conditions. This paper deals with the application of transient free-surface modeling techniques to determine the effects of interruptions and surges of inflow rate on the flow patterns in tundishes. Such events occur during the beginning or end of a pour, whenever ladle nozzles stick, or when ladles are switched in tandem pourings. By tracking the movement of imaginery "markers" through the tundish, these techniques can determine how the distribution of retention times will be affected and when previously trapped inclus ions are likely to be swept into the caster.
(3:15 p.m.)
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(3:25 p.m.) PHYSICAL AND MATHEMATICAL SIMULATION OF MARANGONI CONVECTION IN A
WELD POOL: P. Sahoo, A. J. Paul and T. DebRoy, Department of Materials Science and Engineering. Metall urgy Program, The Pennsylvania State University, University Park. PA 16802. Several low melting-point non-ferrous alloys were melted in an alumina crucible under a controlled atmosphere. A laser beam was impinged at the centre of :the molten alloy pool and the convection at the pool surface was investigated by a photographic technique. The pool temperature was also determined experimentally at several locations. The equations of change were solved to obtain velocity and temperature fields. The predicted temperature and velocity fields were compared with the corresponding measured values. Various dimensionless parameters of importance to the flow were investigated.
PLASMAS FOR METALLURGICAL APPLICATIONS II: Plasma Applications in Extractive Metallurgy Sponsored by the TMS Physical Chemistry Committee Monday, March 3,1986 La Galerie 1 2:00 p.m. Marriott Hotel Session Chairmen: R. H. Nafziger, Albany Research Center, Bureau of Mines, P.O. Box 70, Albany, OR 97321; L. S. Richardson, Idaho Nat. Eng. Lab .. EG&G Idaho, Inc., P.O. Box 1625, Idaho Falls, ID 83415
(2:00 p.m.) BATH SMELTING OF CHROM ITE I N A TRANSFERRED-ARC FURNACE: U. G. C. Robertson, S. Taneka, Imperial College of Science and Tecl1il6T09y. Royal School of Mines, Prince Consort Road, London SW7 2BP. U.K. The ki neti cs of the ca rbotherma I reduction of chrom i te (from the Vanad Mine, Zimbabwe) were first studied at one atmosphere in the temperature range 1350°C to 1750°C. A small-scale (4 gram samples) apparatus was used and the rate of CO evolution was measured. The main variables studied were temperature and fluxing the chromite WIth silica. A laboratory-scale D.C. transferred-arc furnace (40 kW) was developed to continuously smelt friable chromIum are to a hIgh-carbon ferrochrome alloy. The charge (ore + coke + flux) was fed down the center of a single graphite electrode (ELRED) and was smelted in the molten bath. Results will be given on the operating characteristics of the furnace, metal and slag compositions, chromium recovery and the effects of flux i ng with s iIi ca. The power requ i rement to smel t the ore, after an allowance for the measured heat losses, was close to the theoretical value.
36 TMS Annual Meeting
0,
UENCE COAL QUALITY ON ENERGY CONSUMPTION IN PLASMA HEATED TlNG REDUCTION IRON MAKING PROCESSES: J. o. Eds trom, Royal ~4. Stockholm, Sweden, M. J. Tang, Inst. hemical Met., Academia Sinica, Beijing, China.
nst. Tech., S-100
the 1970' s much work has been done to develop new
ing processes based. on smelting reduction. One of these cesses is the Plasmasmel t process I a shaft furnace process ch has been developed by SKF in Sweden.
To decrease
ectricity consumption, a new version that burns coal with xygen has been cons i dered (Plasmaoxygen).
In the present
study, a computer model has been set up to simulate the two types of processes in order to show the effect of variation of the operation parameters, especially the coal quality, and to compare consumption figures. For Plasmasmel t, the lowest erall energy consumption, 3.0-3.3 Gcal/tonne hot metal, is ned when all energy is supplied as electricity. To obtain energy consumption and less surplus gas, the use of a low 1atile coal such as anthracite is advisable.
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(3: 15 p.m.) ANALYSIS
0,
MATERIAL PROCESSING EXPERIMENTS WITH THERMAL
PLASMAS:
D. J. Varacalle, Jr., L. S. Richardson, Idaho National Engineering Lab., EG&G Idaho, Inc., P.O. Box 1625, Idaho Falls, ID 83445.
In this paper, results of theoretical and experimental s~udies on the feasi bil i ty of al uminum production via plasma processing are presented, with preliminary discussions of possible operating condi tions and economics. The regime under conslderation has only gas phase reactlons occurring, exc~pt in the final separation steps where aluminum liquid occurs. Spatial distributions of temperature, velocity, and composition wi thin an argon processing plasma are presented, comparing experimental measurements wi th computer predictions. .4. 180 kW dc, nontransferred arc torch was chosen for both modeling and experimental purposes. Experimental measurements of temperature and composition were primarily performed using spectroscopic measurements of optical emission of the plasma, while laser doppler anemometry (LDA) was used to measure both plasma and particle velocity. Selected experimental multidimensional maps are presented.
(3:45 p.m.) THE PLASMA TREATMENT OF WASTE DUSTS. FINES AND SLAGS: 1.0 Sommerville, A. McLean and C.B. Alcock, Ferrous Meta]lu~y Research Group. Department of Metallurgy and Materials Science,
PRETRANSFORMATION BEHAVIOR RELATED TO DlSPLACIVE TRANSFORMATIONS IN ALLOYS II Sponsored by the ASM-MSD Structures Committee Monday, March 3,1986 Mardi Gras I-J Marriott Hotel 2:00p.m. Session Chairmen: S. S. Hecker, Los Alamos National Lab., Los Alamos, NM 87545; T. R. Finlayson, Monash Univ., Clayton, Victoria, Australia
(2:00 p.m.) INCIPIENT LATTICE HISTABIUTY ANn MARTENSITIC NIJCLEATlON: G.B. Olson ,nd M. Cohen, MIT Ca,"bridge, MA 02139 Electronic calculations of the energetics of homogeneous FCC-RCC lattice jeformations in Na and Fe identify the thermodynamic conditions for lattice instability and the nature of the elastic cons tant anarlO 1 i es accompanyi ng the approach to i nstabil ity. USing an analytical description of the lattice deformation energetics and incorporating a strain gradient energy, the energy of d martrnsitic nucleus with diffuse interfaces is described, allowing for nonclassical nuclei of variable structure. For the case of homogeneous nucleation in defect-free !'laterial, nonclassical nucleation is favored, resembling a localized mechanical instability. The heterogeneous nucleation that controls the transformation in bulk materials is classical in nature, involving localized eillbryo forlilation rather than localized soft-I'lode homophase fluctuations. Because pre-instability phenomena associated with lattice "'etastability do not play an intrinsic role in the transformation mechanism, it is suggested that they should not be termed pretransformation phenomena. This resea rch is sponsored by the Nat i ana I Sc i enee Foundat ion.
(2:30 p.m.) SIMPLE MODELS FOR THE OMEGA PHASE TRANSFORMATION: D. de Fontaine, Department of Materials Science and Mineral Engineering. University of California, Berkeley. CA 94720 In the late sixties, it was recognized that the Omega phase transformation occurring in bcc Ti. Zr and Hf alloys was a disp1acive transition which could be described, at least qualitatively, by simple models. Since the disp1acive wave responsible for the transition to perfect Omega was a Brillouin zone boundary wave, di sp 1 acements and vo 1 ume changes were rather small, in contrast to the classical Martensite case. To account for pretransitiona1 effects and for the transition itself, both rea 1 space and reciprocal space mode 1 have been proposed. Some of these mode 1 s wi 11 be discus sed.
Uni versi ty of Toronto, Toronto, Ontar io, M5S lA4. After a brief review of the necessity and methods available for treatment of the various forms of waste arising from iron and steelmaking operations, a description is given of the plasma reactor developed at the University of Toronto. which has been used to treat such waste materials as well as low and high-grade ores. PartlcuJar attention is devoted to the treatment of electric furnace baghouse dusts which, because of their zinc and lead contents, pose an environmental problem out of all proportion to the quantities generated. It is shown that the plasma reactor yields almost complete separation of the zinc and lead into the gaseous phase, leaving both slag and metal free of toxic elements. The zinc and lead can be recovered either as oxides, or by sOlbe form of rapid condensation, as metals. Ferro-alloy fines and slags have also been treated similarly to yield very high recoveries of the valuable alloying elem.ent in the metal phase.
(4: 15 p.m.)
(3:00 p.m.) X-ray and Neutron Investigation of Martensitic and Pre-Martensitic Phenomena, S. M. Shapiro, Physics Department, Brookhaven National Laboratory, Upton, New York 11973 and S. C. Moss, Department of Physics, University of Houston, University Park, Houston, TX 77004 High resolution diffuse X-ray and neutron scattering provide unique information about spatial correlations in materials undergoing Martensitic trans formt ions . Inelastic neutron scattering gives details about the microscopic dynamics of the phase transition - in particular, the role of the phonons. A review of neutron and diffuse X-ray studies on martensitic phase transitions will be given with particular emphasis on the relationship of observed phonon anomalies to the low temperature phases. A more detai led discussion of the neutron and X-ray experiments on the shape memory alloy NiTiCFe) and other ~ phase materials will be presented.
(3:30 p.m.)
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A POT TEST TECHNIQUE FOR EVALUATING PLASMA SMELTING OF FERRO-
ALLOYS: K. J. Reid, J. J. Moore, M. J. Murawa, N. M. Girgis, A. Brent, MineraT"Resources Research Center, 56 East River Road, Minneapolis, MN
55455.
A plasma pot test is described in which the mineral, reductant and flux materials are mixed and fed into a small graphite crucible Which acts as the anode in a closed in-bath plasma smelting system. The plasma is generated by striking an arc between a vertical cathode electrode positioned above the pot and the crucible. This experimental approach provides a relatively inexpensive and rapid means of assessment of the applicabili ty of in-bath plasrM.· smelting of mineral oxides as an alternative route for the production of high carbon ferroalloys. Several mineral-reductant combinations have been investigated with respect to the degree of metallization achieved, partitioning of elements between the slag and the metal, mineral oxide reduction sequence and poss i b Ie reduct i on mechan isms, and recovery ra tes. The paper presents experimental results and discusses the usefulness of such a test in assessing the application of plasma smelting to ferroalloy production.
(3:40 p.m.) 'MODULATED LATTICE RELAXATION' IN G-BASED PREMARTENSITIC PHASE: Y. Yamada, Faculty of Engineering Science, Osaka University, Toyonaka Osaka 560, Japan Recent X-ray studies on TiNi(Fe) alloy by Shapiro et al. show that incommensurability of satellite reflections changes from Brillouin zone to Brillouin zone, giving overall 'swirl' like shift pattern in the reciprocal space which precludes any simple incommensurate wave model. We have succeeded to reproduce the intriguing shift pattern observed, based on two simple assumptions: (i) existence of soft phonons at q~1/3[1101 (ii) existence of 'embrios' of low temperature martensite phase. The proposed features of premartensitic phase suggest a possible microscopic mechanism of martensite transformation in general as well as of w-phase formation.
TMS Annual Meeting 37 (4:10 o.m.) ~-PHASE STABILITY AND MARTENSITIC NUCLEATION IN HUME-ROTHERY ALLOYS: B. Verl i nden and L. Del aey, Kathol i eke Uni Yersi teit Leuyen, Dept. of Metallurgy and Materials Engineering, de Croylaan 2, 3030 Heyerlee, Belgium. In the localized nucleation theory of martensite, the elastic constants of the matrix B-phase are an important factor to explain the (in)stability of the pre-martensitic matrix and the start of the martensitic transformation. Some factors influencing the elastic constants and consequently the nucleation characteristics will be discussed. The influence of the alloy composition on C', the anisotropy and Ms can, for binary and some ternary alloys, be described by some empirical rules based on some simple physical parameters. The influence of temperature and stress on the stabil ity of the B-matri x will be di scussed and some remarks concerni ng the i nfl uence of orderi n9 wi 11 be gi yen.
(4:40 p.m.) X-RAY AND NEUTRON DIFFRACTION ANOMALIES PRECEDING THE MARTENSITIC PHASE TRANSFORMATION IN Au-Cu-Zn ALLOYS: A.Nagasawa and T.Makita; Nara Women's University, Nara 630, Japan. N.Nakanishi; Konan University, Kobe 658, Japan. M.Iizumi and Y.Morii; Japan Atomic Energy Institute, Tokai 319-11, Japan. Several kinds of anomalies have been observed as the preceding phenomena of the martensitic transformation in many B-phase alloys. Such precursors relate closely to the transformation mechanism and predict the schema of the transformation. The transformation behaviours, on the other hand, are influenced so much by thermal procedures such as quenching and aging of mother phase. In the present paper, we will emphasize the importance of such effects on the premartensitic anomalies in order to understand the nature of the martensitic transformation. Especially we will concern with the X-ray and neutron diffraction anomalies found recently by us near 2/3<110>. They are induced by quenching and enhanced by aging.
PROCESS MINERALOGY APPLICATIONS TO MINERAL DEPOSITS: EXPLORATION, PREDICTIVE METALLURGY Sponsored by the TMS-SME Process Mineralogy Committee Monday, March 3,1986 La Galerie 3 2:00 p.m. Mariott Hotel Session Chairmen: David J. T. Carson, Noranda Exploration Company, Ltd., Suite 400, 55 Yonge Street, Toronto, Ontario, M5E 114, Canada; Andreas H. Vassiliou, Department of Geological Sciences, Rutgers University, Newark, NJ 07102
(2:00 p.m.)
EXPLORATION FOR BURIED TALC BODIES THROUGH ANALYSIS OF THE RESIDUAL SOILS: A. M. Blount t Geology Department, Rutgers University, Newark, N. J. 07102
Residual soils associated with buried talc deposits have been studied by x-ray diffraction in three talc producing regions: Montana, Alabama and Pennsylvania. Significant amounts of talc are found to be present in the soil above and in the soil derived from hydrothermal alteration zones surrounding such deposits. X-ray diffraction sample preparation techniques vary for each region because the talc is concentrated in different particle-size fractions in each soil. The talc is primarily in the silt fraction in Montana soils but in the clay fraction in Alabama soils. Methyl Isobutyl Carbinol (MIBC) has been used, with very encouraging results, for screening of soils for the presence of talc. As with x-ray diffraction, the procedures must be modified according to specific characteristics of each soil type. This technique permits real-time monitoring of progress during field work.
xenotime at depth. The lowermost part of the T-zone displays a profound enrichment of niobium in columbite. Gallium substitutes for aluminum is albite in the footwall assemblages of the deposit. Whereas beryllium and yttrium-bearing minerals lend themselves to recovery by flotation, RE-elements and niobium-bearing minerals have shown preliminary amenability to gravity techniques. Acid and caustic leach tests have been conducted on gallium-bearing assemblages. (3:00 p.m.)
PREDICTIVE METALLURGY OF THE TALLY POND MASSIVE SULPHIDE DEPOSIT, NEWFOUNDLAND: J.L. Jambor, CANMET, Ottawa, KIA OGI and D.].T. Carson, Noranda Exploration Co. Ltd., Toronto, M5E IJ4
The Ordovician Tally Pond deposit contains three known pyritic massive sulphide zones (North, South, Southeast) with combined reserves of about 450,000 tonnes grading 3% Cu and 3% Zn. The deposit is a potential source of feed to replace the exhausted Buchans ores. Economic minerals at Tally Pond are chalcopyrite, sphalerite, minor galena, and very minor hessite. Distinct differences in grain size, texture and alteration are expected to cause wide variations in metallurgical response of the three ore zones. Digenite-covellite alteration is sufficiently strong in the South Zone that unacceptable copper losses and zinc activation are predicted. The Southeast Zone has the coarsest grain sizes; excellent metallurgy is anticipated. The North Zone ore has a fine, tightly packed pyritic structure and will require a very fine grind to yield acceptable recoveries. The predictive metallurgy, based on polished section studies, is compared with the results of subsequent metallurgical benchtests on drill core samples.
(3:30 p.m.)
MINERALOGICAL CONTROLS ON THE GOLD, MOLYBDENITE AND BARITE METALLURGY AT THE GOLDEN GIANT GOLD DEPOSIT, HEMLO, ONTARIO: J.E. Clemson, Noranda Exploration Co. Ltd., Toronto, M5E lJ4.
The Golden Giant mine is being developed on the recently discovered Hemlo ore zone. The reserves at Golden Giant are 19 million tonnes grading 10.1 g/t Au, 0.1% molybdenite, 1.5 g/t Ag and 10-13% barite. The orebody is 3-40 m thick, occurring in steeply-dipping Archean schists. Major minerals are quartz,Kfeldspar, muscovite, barite, calcite and pyrite. Minor minerals include molybdenite, stibnite, realgar, orpiment, cinnabar and magnetite. The gold-bearing minerals are native gold and minor aurostibite. Gold occurs on silicate grain boundaries and recoveries of +95% are achieved by cyanidation and carbon-inpulp processes. Marginally reduced gold recoveries are due to the insolubility of aurostibite. Molybdenite occurs on silicate grain boundaries and is liberated during grinding. Molybdenum concentrates contain deleterious As, Sb and Hg due to the presence of liberated grains of realgar, orpiment, stibnite and aktashite. Testwork has produced barite concentrates grading 85-95% barite; the main contaminant is liberated calcite.
(4:00 p.m.)
THE COMPOSITION AND ORIGIN OF THE BEEMERVILLE CARBONATITE, SUSSEX COUNTY, NEW JERSEY: A. H. Vassiliou, Dept. of Geological Sciences, Rutgers University, Newark, N. J. 07102 and K. D. Seborowski, Woodward-Clyde Consultants, 201 Willowbrook Blvd., Wayne, N. J. 07470.
The carbonatite is part of the Beemervil1e alkalic rock complex of late Ordovician age and is the only such occurrence in the eastern United States. The carbonatite exhibits several modes of occurrence as well as mineralogical, geochemical, petrological and textural variation. It outcrops as dikes within the Martinsburg Formation, as xenoliths within volcanic diatremes and as the matrix material encasing xenoliths in diatremes. Based on petrographic analysis, both dike-type and diatremetype occurrences are classified as "silicocarbonatite". Based on electron microprobe and neutron activation analyses, it is further classified as an "apatite-magnetite variety" due to its relatively low rare-earth content. Field and analytical data suggest that the carbonatite resulted from the differentiation of an alkalic parental magma which probably gave rise to the carbonatite fluid phase and an alkaline residuum.
(4:30 p.m.)
(2:30 p.m.) GEOLOGICAL AND MINERALOGICAL ASPECTS OF THE THOR LAKE BERYLLIUM, YTTRIUM, RARE-EARTH, TANTALUM-NIOBIUM, GALLIUM, DEPOSITS, NORTHWEST TERRITORIES: D. L. Trueman, Highwood Resources Ltd., 400, 80S-8th Avenue S.W., Calgary, Alberta, Canada.
Beryllium mineralization occurs in 3 of S areas of al teration associated with Proterozoic alkaline magmatism at Thor Lake, NWT. Canada. In the T-Zone, the area of primary economic interest, beryllium is confirmed to phenacite near surface but with increasing depth is associated with bertrandite, helvitedamalite, and gadolinite. RE-elements hosted by bastnaesite, synchisite, and parisite at surface associate with yttrium is
CHANGES IN THE COBALT MINERALOGY or TILE KIDO CREEK fJ,\SSlVE SULFlDE OREBODY AND THEIR EFFECT ON PL,\~T flETALLURGY, J. D. Scott, Kidd Creck Minf::'s Ltd., B-2002, Timmins, Ontario. P4N 7KI
Carrollite (Co CuS ) occurs as a minor constituent of the 4 2 bornite zone of the south orebody. Above the 1600 lev('l it reports to the copper concentrate but 2000 level material contaminates the zinc concentrate. In all cas('s, the carrollltC' occurs as large (2 mm to 2 cm) octahedrdl crystals in massive chalcopyrite and/or bornite. It has been found that 2000 l('vel crystals are monomineralic and activated during zinc flotation. Upper level crystals, however, display d fine-scale intergrowth of bornite along the cubic cleavage directions. they therefore float as bornite in the copper circuit. The flotation responsE'
38 TMS Annual Meeting of this carr-allite is different to that of other thiospinels dnd may be reLlted to its significant selenium content; the selenium level in carrallite from 800, 1200, 1600 and 2000 levels is 1.2, 3.8, 6.6 and 8.9°/" respectively.
T£'TION TECHNOLOGY II: Inert Anode Technology Sponsored by TMS Light Metals Committee Pontchartrain Ballroom D Sheraton Hotel Chairman: A. R. Johnson, Kaiser Aluminum & ult:II11\;al Corp., P.O. Box 877, Pleasanton, CA 94566
FOR HALL CELLS: Alan D. McLeod. John S. Haggerty, and Donald R. SadowaYt Dept. Materials Science and Engineer.ing, Hassachusetts Institute of Technology, Cambridge, MA. 0213';1.
As part of an investigation of candidate inert anode materials for Hall cells, fundamental property data are being measured. As well, performance in laborator~-scale Hall cells, operating at current densities up to 5 A/cm is being assessed. The first generation of materials is selected from the NiO-Fe203 and CoO-Fe203 systems. By laser processing, monocrystalline and grain oriented polycrystalline specimens have been produced. The use of a current interrupter in conjunction with an aluminum reference electrode has facilitated overvoltage measurements for oxygen evolution as a function of current density.
(2:25 p.m.) HALL CELL OPERATION WITH INERT ANODES: Frank W. Baker and Richard L. Rolf, Alcoa Technical Center, Alcoa Center, PA 15069 A 2500 A Pi lot Cell was constructed and operated with inert anode assembl ies to develop cell operating procedures and eval uate anode performance for extended periods of time. Isostatically pressed anodes representing Ni-Fe-O cermet materials were diffusion welded or mechanically joined to metall ic stub material s prior to preheating at 1000°C and transferring to molten bath. Cell operating parameters were optimized for inert anode operation including control of Al 0 concent rat ions at satura ted I eve Is. In suI at i ng techn i ques we~e3 developed preventing anode cracking and failure due to thermal shock during initial installation and subsequent operation. Autops i es of a II anodes were conducted to correl ate anode performance with cell operating conditions. High ~203 levels in bath were required for minimum anode corrosion confTrming bench scale studies in smaller cells.
(3:40 p.m.) CORROSION AND PASSIVATION OF METALS AND ALLOYS USED IN CERMET INERT ANODES IN CRYOLITE-TYPE ELECTROLYTES: Gary P. Tarcy, Alcoa Laboratories, P. O. Box 772, New KenSington PA 15068 Cermets are a class of materials that offer promise as inert anodes in aluminum smelting because of the low solubilities of certain oxides in cryolite and high conductivities of the metal phase. Electrochemical dissolution of the metal phase in the cermets can lead to premature failure of the anode. The elect rochemi ca I corros i on of vari ous meta I s and a II oy cand i date phases has been investigated with linear sweep voltammetry, galvanostatic polarizations, and microprobe elemental dot map analysis. The investigation showed that nickel is an unacceptable metal for cermet anodes. Noble metals are cathodically protected from anodic dissolution while copper/nickel alloys undergo a passivation. The passivation is strictly val id with cermets only and dependent on the use of copper rich alloys and high alumina concentrations in the melt. The passivation is independent of microstructural size of the alloy particles, concentration of the alloy phase, current density, dissolved aluminum metal and time.
(4:05 p.m.) MANUFACTURING PROCESSES USED FOR THE PRODUCTION OF INERT ANODES: John D. Weyand, Ceramics Division, Alcoa Technical Center, Alcoa Center, PA 15069. Inert anodes manufactured from the raw material oxides of NiO and Fe 0 and metal s such as Ni have been demonstrated to be promisfn~ electrode materials for the electrolysis of aluminum. Several process flow sheets and manufacturing methods have been utilized to fabricate inert anode shapes to density and compositional specifications. Raw materials were agglomerated by open and closed system spray drying into free-flowing pressable powder, isostatically pressed, and sintered under cont ro 11 ed atmospheri c cond it ions to fabri cate anodes for Ha 11 cell production of aluminum. Raw materials and process conditions employed and the properties of manufactured inert anodes wi 11 be exp I ai ned.
SENSORS: DEVICES, MATERIALS AND PROCESSING II: Pyroelectric, Opth;al and Gas Sensors Sponsored by the TMS Electronic Devices and Materials Committee Monday, March 3, 1986 Bissonet 2:00p.m. Marriott Hotel Session Chairman: E. N. Sickafus, Ford Motor CompanyResearch Staff, P.O. Box 2053, Dearborn, MI 48121-2053
(2:50 p.m.)
(2 :00 p.m.)
MATERIALS DEVELOPMENI FOR INERT ANODES: S. P. Ray, Ceramics Division, Alcoa Technical Center, Alcoa Center, PA 15069
Non-Optical Pyroelectric Sensors, Jay N. Zemel, Center for Chemjcal Electronics, University of Pennsylvania. Philadelphia, PA 19104.
It is well known that the use of inert electrodes may lead to compact cell designs and improved efficiency in Hall cells for aluminum production. Refractory hard metal, e.g., titanium diboride is clearly the leading inert cathode material. In the past a number of materials have been proposed for use as inert anodes, but most of these materials lacked the stringent requirements of inert anodes. The present paper describes the selection and evaluation of a number of cennet materials in the Ni-Fe-O and Ni-Fe-Cu-O systems. The cennet materials have acceptable electrical conductivity. The allBUinum produced during bench scale electrolysis tests using these anodes contains low levels of anode constituents. The effect of Hall cell operation on anode microstructure is discussed.
(3: 15
D .m.) SOLUBIL !TIES OF OXIDES FOR INERT ANODES IN CRYOLITE-BASED t~ELTS: David H. DeYoung, Alcoa Laboratories, P. O. Box 772, New Kensington, PA 15068
The solubilities of NiO, Fe203' and NiFeZ04 have been measured in NaF-A1F3-AI203-CaFz melts. These oxides are components of inert anodes that have been developed for the Hall-Heroult cell, and the work was conducted as a prelude to determining the dissolution mechanism for these anodes in Hall cell el ectrolytes. Measurements were made as a function of temperature and mel.t composition. The effects of various additives such as MgFZ' LiF, Zr02' and SiOZ were also determined. Except for temperature, the concentrations of A1 Z03 and Si02 had the greatest effect on solubil ities--they decreased with increasing Al203 and decreasing Si02' The solubility of Fe203 slightly decreased with decreasing bath ratio, while no change was detectabl e for NiO. The sol ubil ity of the ferrite was consistent with the values for the simple oxides and the standard free energy of formation of the compound.
Pyroelectric materials like lithium tantalate have temperature dependent electric polarization vectors. Changes in temperature induce changes in the surface charge that are readily measured. As a result. the well known pyroelectric optical detector is capable of sensing heat flows of the order of 10 pW. This sensitivity can be used to good advantage in other types of oonoptical applications such as pyroelectric anemometry (PA) and scanning calorimetry and/or enthalpimetry. The PA has a minimum dynamic range of 6 orders of magni tude while the scanning calorimeter/entha1pimeter can detect energy flows as small as 1 llW. Work from other laboratories also will be presented.
(2:35 p.m.) FIBER OPTIC SENSORS, Anthony Dandri dge, Code 6574, Na va I Resea rch Laboratory, Washington, DC 20375-5000. During the past seven years, many tyoes of fiber optic sensor have been demonstrated. Many papers have discussed the advantages of fiber optic sensors (FOS) for specific applications. These advantages include sensitivity, size, weight, immunity to EMI, cost, and the extreme versatility of the sensor head. By 1983, FOS had been successfully demonstrated in quasi-operational environments. Further tests in hostile environments will indicate the viability of FOS. This Daper will review the general field of FOS. However, emphasis will be placed on the advances in the techno I 00Y achi eved duri ng the Das t two yea rs. Soec ifically, advances made in the high-technology end of the fiber optic sensor spectrum will be considered.
(3:10 p.m.)
Break
TMS Annual Meeting 39 (3:25 p.m.)
a measurement of only two size distributions, precipitate growth kinetics as a function of precipitate radius.
SILICON BASED GAS SENSO~S AND PROCESSING. Wen H. Ko and Q. H. Wu, Electronics Design Center, Case Western Reserve University,
Cleveland, Ohio 44106 and Scott C. Chang, G. M. Research Labora*Research sponsored by the Division of Materials Sciences, U.S. Department of Energy under Contract No. DE-ACOS-840R21400 with Martin Marietta Energy Systems, Inc., and by Conacyt-PCCB-
tories, Warren, Michigan 40090. Metal oxide gas sensors for reducing gases are reviewed.
Tin
oxide sensors are used as an example to illustrate their char-
BNA-020348, Mexico.
acteristics. The device operates at 200 to 450°C; the gas concentration is measured by the change of resistance. Because of the processes used. the device properties may vary from run to run. The response time is long and the standby power is high. Silicon based tin oxide gas sensors are being investigated. Tin oxide is sputtered onto a thin silicon diaphragm with the heating element and a temperature sensor built into the silicon substrate. A small area is heated to a temperature controlled by a temperature sensor in a feedback loop, thus reducing the power and the response time. By scanning the temperature of the sensor film, one may improve selectivity and sensitivity and sense several gases with one sensor. Laboratory results and fabrication processing will be reported.
tGuest scientist at ORNL. Permanent address: Instituto de Fisica, University of Mexico (UNAM), Apdo. Postal 20-364, 01000 Mexico, D.F., Mexico.
(4:00 p.m.) METAL
OXIDE
BASED
GAS
Staff, Ford Motor Company,
SENSORS:
P.O.
E.
Box
M.
2053,
Logothetis. Research
Dearborn, Michigan
4B121.
Solid-state gas sensors based on metal oxides are finding an increasing use in pollution control, safety, process control and other applications. Several types of sensors have been developed such as potentiometric and amperometric electrochemical cells, semiconducting resistive devices and interface-type sensors. This talk will briefly review the operation and the characteristics of these sensors and the relationship between materials properties and sensor performance. The response of a metal oxide gas sensor involves many physical processes such a) exchange of molecular species at the gas/solid interface, b) motion and changes in the concentration of ions and electrons in the solid, and c) gas transport. These processes and their influence sensor response will be analyzed using the resistive-type oxygen sensor as an example. Finally, the important issue of sensor selectivity and means for improving it will be discussed.
SURF ACES & DIFFUSION
TMS-AIME General Abstract Session Monday, March 3,1986 Bacchus Marriott Hotel 2:00 p.m. Session Chairman: R. W. Heckel, Dept. of Metallurgical Engineering, Michigan Technological University, Houghton, MI49931
(2:00 p.m.) SURFACE SEGREGATION OF PHOSPHOROUS AND SULFUR STAINLESS STEEL:* Yongbin 1m and Steven Dany1uk,
Civil Engineering, Mechanics, and Metallurgy, Illinois at Chicago, Chicago, 11 60680
IN TYPE 304 Department of
University
of
The kinetics of surface segregation of P and doped type 304 stainless steel has been determined by means of Auger electron spectroscopy (AES). Five experimenta 1 heats containing different bulk concentration of P and were fabricated in a vacuum induction furnace. The surface segregation kinetics of P and S were studipd by in situ heating experiments at 100°C intervals over the temperature range 550°C to 8S00e. The kinetics of P and S segregation appears to be diffusion controlled and proportional to the square root of time in agreement with a surface segregation theory based on McLean's Model. The phosphorous segregation is a maximum of '\.. 30 a/o at '0 75()°C. *Research supported in part by Institute, Project No. 62-440.
the
American
Iron
and
Steel
(2:20 p.m.)
* J. H. Schneibe1 and L. Martinez, t Metals and Cetainics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 ON INTERFACIAL ENERGY MEASUREMENTS:
We propose a method to determine precipitate-matrix interfacial free energies and compare it to a somewhat different technique which was recently successfully employed by Bauman and Williams in the Al-Li system. Given suitable experimental conditions, the technique suggested by us may also be useful in determining, from
(2:40 p.m.) LASER RAMAN SPECTROSCOPIC CHARACTERIZATION OF METAL SURFACES:
B.H. Loo*, Y.G. Lee* and D.O. Frazier**, *Department of Chemistry, The University of Alabama in Huntsville, Huntsville, AL 35899, **Space Science Laboratory, NASA/MSFC, Huntsville, AL 35812
The surface-enhance~ Raman scattering (SERS) effect has attracted much attention recently. SERS is a process in which the Raman scattering iDtensity by molecules or ions adsorbed on mi~rosgopicallY rough metal surfaces is enhanced by factors of 10 -10 compared with the intensity expected for the nonadsorbed species at the same concentration. Such enormous enhancements totally overcome the traditional low sensitivity problem associated with the normal Raman scattering process. With the SERS technique, specific information regarding the chemical identity, structure and orientation of the adsorbates on metal surfaces can be readily obtained. This type of information is of particular interest in industrial processes such as corrosion inhibition, catalysis, electroplating and adhesion. In this work we demonstrated the usefulness of the SERS technique in the study of dini triles, thioacetamides, thioureas and imidazoles on Cu and Ag surfaces.
(3:00 p.m.) SURFACE FORCES AND ADHESION IN CONTACTING SOLIDS: • G. Poletti.
1st. Fisio!. Gen. e Chim. Bio!.. Universi tel di Milano, Milano , Italy. A dynamic technique to measure surface forces in contacting sol:ids is discussed toghether with an experiment included by ESA in the payload of the EURECA flight. The main objectives are the measurement of surface force and surface energy in the contact area between real bodies and the assesment of their dependence of mechanical and physical parameters. A small sphere impacts against a target and time behaviour of contact force, contact time and resti tution coefficient are measured as a function of the incomirg: sphere veloci ty. Computer simulation of the experiment indicates that surface force effects can be measured provided the experiment is carried out in microgravi ty under ultra high vacuum. The characteristics of the experiment and of the facility designed to fly on board of Eureca in 1988 are shown. Potentialities of this new technique for microgravi ty material science research are discussed
* This work is financed by the Italian PSN-CNR. (3:20 p.m.) PREDICTING INTERDIFFUSION IN NI-RICH, Ni-Cr-A1 ALLOYS AT 1100 0 and 1200°C, J. A. Nesbitt, NASA Lewis Research Center, 21000 Brookpark Road, Cleveland, OH 44135, and R. W. Heckel, Dept. of ~leta11urgica1 Engineering, Michigan Technological University, Houghton, MI 49931. Ternary interdiffusion coefficients were measured in the Ni solid solution phase (y) of the Ni-Cr-A1 system at 1100° and 1200°C. Extensive use was made of both Y/y and y/y+S diffusion couples. Results showed that DAlAl is approximately four times greater than DAler , while DerAl and Derer are of the same magnitude. For all concentrations, DAlAl is two to three times greater than Derer' Both DAlAl and DAler increase with increasing A1 concentration, whereas De Al and Derer show 1 itt 1e concentration dependence on Cr alone. A ternary, finite-difference interdiffusion model was employed to predict concentrati or.ldi stance profil es fpr the Y/'! coup1 es util i zing the concentration dependence of the measured diffusivities. Good agreement was observed between the predi cted and measured concentration profile,s for both 1100° and 1200 °C. (3:40 p.m.) INTERDIFFUSION IN THE QUINARY Ni-Co-Cr-Fe-~10 SYSTH1:* J. J. Xu and M. A. Da~ananda, School of Materials Engineering, Purdue Universlty, est lafayette, IN 47907 Interdiffusion in solid-solid couples assembled with quinary Ni-Co-Cr-Fe-Mo (fcc) alloys have been investigated at 1300°C for the detenni nati on of di ffusi on paths. The concentration profi 1es of the couples examined on the basis of relative concentration va ri ab 1es are cha racteri zed by common cross-over compos iti ons. Interdiffusion fluxes are calculated directly from the concentration profiles. The diffusion paths for the quinary couples are presented as a set pf three partial diffusion paths and represented on the basis of four characteristic path parameters.
* Research
supported by U. S. Department of Energy under contract DE-AC02-81 ER10814.
(2:30 p.m.) BETWEEN BULK AG AND ELECTROPLATED AU THIN FILMS' and M. J. Cieslak, Sandia National Laboratories,
diffusion couples were produced by plating Ag substrates u.
The Au films were 250 nm thick and showed no evidence
porosity. The diffusion couples were isothermally annealed in the temperature range 482 to 700 C. The surface composition of
each sample was determined by Auger electron spectroscopy. The concentration profiles in the Au films were measured by using the Auger microprobe in the sputtering mode. The diffusion equation was solved numerically to determine the effecti ve interdiffusion coefficient. The activation energy for interdiffusion was 0.35 eV, which is smaller than volume diffusion (2.99 eV), grain boundary diffusion (1.41 eV), or surface diffusion (0.46 eV). The pre-exponential factor was 1. 9E-09 cm*cm/sec, much smaller than volume, grain boundary or surface diffusion. These resul ts t a complex mechanism which may contain volume and defect-
ts.
:20 p.m.) EFFECT OF MECHANICAL POLISHING ON THE APPARENT HYDROGEN PERMEATION RATE IN IRON SINGLE CRYSTALS Jong-Lam Lee 1 ,2, Yong-Ki Park l and James T. Waber 1 • 2 IDepartment of Materials Science and Engineering, Northwestern University,Evanston, 1L 60201 and Physics Department, Michigan Technological University, Houghton, MI 49931 It is shown that mechanical damage introduced by mechanically polishing a single crystal reduces the hydrogen diffusion. rate through it. Recently, pOSitron annihilation was used to show that the defect (probably dislocation) concentration, introduced by mechanical polishing, decreases linearly with the depth of metal removed by chemical polishing. The hold-up of hydrogen diffusing through a dislocation-containing specimen also decreases with the removal depth. The hydrogen readily diffuses out of the damaged zone in less than 4 h at room temperature. The progressive decrease in the break-through times shows that H in the traps. The great experimental variabiUty of the diffusion rates determined by electrolytic charging may be thus explained in part since mechanically polished specimens have almost universally been used.
Ex-Vessel Search Techniques for Fuel and Fission Products: Owen, Consultant, 530 W. 2nd St., Hummelstown, PA 17036; C. Distenfc1d, GPlINC, TMI-2 Admin. Bldg., Middletown, PA 17057
~
The sienificant damage to the TMI -2 core [esul ted in fuel debris and fission products beinE dispersed into the reactor coolant system and connecting piping within the reactor building and the auxiliary and fuel handling buildin8. Locating fuel debris and differentiating it from fission products is essential to safe and efficient recovery planning for decontamination, radiation control, waste disposal, emergency procedures and crit lcali ty prevention. Some special radiation detecUr)f1 equipment was developed and is in use at TIll such as mobile and portable garrnna spectrometers, miniaturized neutron detectors and a garuna camera. Characterization task planning requires careful consideration of equipment capabilities, env.ironmental and physical restr.ictions to both personnel and equipment, data needs and cost. TIle search approach and equipment selection when faced with such considerations, is discussed with emphasis on eqUipment of potentia] use in normal plant opE'rations.
(3:00 p.m.) OFFSITE SHIPMENT AND DISPOSAL OF TMI-2 CORE AND WASTES: G. J. Quinn, EG&G Idaho, Inc., P.O. Box 88, r1idd1etown, PA 17057 The TtII-2 core debris will be packaged into canisters that will be shipped to the Idaho National Engineering Laboratory (INEL) for use in an accident evaluation examination pronram. Some HlI-2 cleanup wastes have a1 ready been shipped fro" TMI and utilized in various DOE waste immobilization research and development programs. Other wastes which cannot be disposed of in a commercial waste burial site will be shipped to INEL for retrievable storage until suitable disposal, such as a hiqhlevel waste repository, becomes available. The HlI-2 core debris will be shipped in a new desinn rail spent fuel shipping cask that meets the require"ent of 10CFR71.63 for double containment of Pu. Each level of cask containment has "leaktight" seals per AllSI N14.5. A one-quarter scale model of the rail cask was successfully tested in a series of 30 foot drops onto an unyie1 dinn surface and 40 inch drops onto a puncture bar.
(3:45 p.m.)
TMI-2 ACCIDENT: Cleanup Progress and Value to Industry II Sponsored by the TMS/ ASM-MSD Nuclear Metallurgy Committee Monday, March 3, 1986 Iberville 2:00 p.m. Marriott Hotel Session Chairmen: J. T. A. Roberts, Nuclear Power Division, Electric Power Research Institute, 3412 Hillview Avenue, Palo Alto, CA 94303; Melvin L. Bleiberg, Advanced Energy Systems Division, Westinghouse Electric Corp., P.O. Box 10864, Pittsburgh, PA 15236
(2:00 p.m.) TMI-2 Defueling: Techniques and Progress: R.H. Fillnow, GPUNC, Government & Industry Programs, TMI-2 Admin. Bldg., Middletown, PA 17057; J.C. DeVine, GPUNC Tech. Plan., TMI-2 Admin. Bldg., Middletown, Pel l7057 Defueling the damaged TMI -2 core has meant meeting the challenge of developing techniques and equipment for a first-time performance of a difficult task. Complicated by a poli tical and regulatory environment that was Wlprepared for a task of this magnitude, procedures and equipment are being developed for an efficient, cost-effective defueling, handling and shipping operation. Techniques and tooling for the defuel ing activi ty included consideration of potential and known metallurgical condi tions of a core consisting of partial assemblies and pieces of structurals; fused core material potentialJy bonded to core support structurals; and loose granular and partially agglomerated debrjs. Support equipment had to meet criteria which assured personnel protection from und.ue radiation exposure and potential fission product release. It was necessary to develop a capability for remotely controlled operations as well as manual tool manipulation. A method of packaging fuel in containers was developed that was effective in standardizing fuel handling and shipping.
TMI-2 Decontamination Technology Development: Cindy G. Hitz, GPUNC, P.O. Box 480, Middletown, PA 17057; C.P. Deitete, Analytical Resources, Inc. P.O. Box 6617, Wyomissing, PA 19610 The March 1979 accident at TMI -2 has provided a very necessary, as well as unique, opportunity to demonstrate the use of decontamination technologies for the removal of radioactive material from plant internal systems, tmprotected surface areas, operational components and systems. Subsequent operations to recover the damaged unit necessitated considerable effort to remove and concentrate the radioactivity in order to ensure the safety of the public and reduce the radiation exposure to plant workers. During these operations, a large m.unber of decontamination teclmiques have been researched for application to the recovery of the damaged reactor. Several methods have been demonstrated in actual radioactive operations at TMI-2, with varying degrees of success. An evaluation of these demonstrations, detailing comparative success rates and measured dose reduction benefits will be presented. Techniques presently being developed for application to decontamination cleanup operations at TMI-2 will also be discussed.
(4: 15 p.m.)
ROLE OF "ROBOTS" IN ACCIOENT RECOVERY: Paul Bengel, GPUN Corp., P. O. Box 480, Middletown, PA 17057, and Sheldon Lefkowitz, Pentek, Inc., 1026 Fourth Avenue, Coraopolis, PA15108. High radiation levels following accidental releases or radioactivity at nuclear power plants have motivated industry to develop remotely operated vehicles to perform surveillance, sample retrieval and decontamination functions. While te1eoperated manipulators have been used for years to perform "hot" cell oriented nuclear work, the added dimensions of performing unanticipated work and data collection in general plant areas has required the development of remote mobile technology. Several vehicles were developed specifically for use during recovery following the TMI-2 accident. Other vehicles developed at FFTF were used to support work at TMI-2. Remote camera inspection systems also played a vital role in TMI-2 core surveillance as well as routine surveillance of the highly contaminated Reactor Building. These technology developments are commercially available, affordable, re1 iab1e, and absolutely essential to managing personnel radiation exposure in the post-accident environment.
TMS Annual Meeting 41
(4:20 p.m.)
UNDERCOOLED ALLOY PHASES II: (Hume-Rothery Memorial Symposium) Spomsored by the TMS Alloy Phases Committee Monday, March 3,1986 Mardi Gras E 2:00 p.m. Marriott Hotel Session Chairman: E. W. Collings, Batelle Memorial Institute, Columbus, OH 43201-2693
DENDRITIC GRmlTH IN A SUPERCOOLED ALLOY MELT: V. Laxmanan,
Visiting Scientist, NASA Lewis Research Center~T1Stop 49-3. Cleveland, Ohio 44135. Concurrently, Department of f:etallurgy and Materials Science, Case \~estern Reserve University. Cleveland, Ohio 44106. A simple model for dendritic growth in a supercooled~ binary, alloy melt has been presented. The model accounts for "interactions" between nei ghbori ng dendr; tes and can thus descr; be the growth of an "array" of dendrites from a mold wall, for example, into a remnant liquid which is supercooled. The solute diffusion field is calculated in an approximate manner,
following a methodology first developed by Zener and Hillert. It will be shown. strictly from steady-state considerations alone
and without resorting to marginal stability arguments, that the dendrite tip growth velocity first increases and then decreases as the alloy composition is increased.
(2:00 p.m. METASTABLE PHASE FORMATION BY PULSED LASER QUENCHING.
Frans
Spaepen, Division of Applied Sciences, Harvard University, 29 Oxford Street, Cambridge, MA 02138.
TUESDAY AM
Irradiation of a metallic surface with a short laser pulse leads to melting and subsequent quenching of a thin layer. If the
kinetics of crystal growth are slow compared to the rate of heat removal, the crystal-melt interface temperature can fall far below the equilibrium melting temperature. As a result, metastable phases can form.
Since the cooling rates in pulsed
laser quenching are much higher than those in other melt quenching techniques, some unique metastable phases can be formed. Examples for a variety of alloy systems will be given.
(2:35 p.m.) INTERFACE RESPONSE FUNCTIONS FOR RAPID ALLOY SOLIDIFICATION: THEORY AND EXPERIMENT*, Michael J. Aziz, Solid State Division, Oak Ridge National Laboratory, Oak Rldge, TN 37831. The deviations from local equilibrium at a rapidly moving solidliquid interface are well documented. The fraction of solute atoms in the liquid at the interface that joins the crystal during rapid solidification approaches unity and the interface temperature drops. A kinetic theory will be presented that predicts the amount of solute incorporation and the amount of interfacial undercooling in terms of the interface speed during rapid solidification. Predictions for systems of interest will be presented. Experiments to test the theory will be discussed. *Resea rch sponsored by the Di vi s i on of Materi a 1s Sci ences, U. S. Department of Energy under contract DE-AC05-840R214DO with Martin Marietta Energy Systems, Inc.
ALTERNATE ALLOYING FOR RESISTANCE III: Aqueous Corrosion Sponsored by the TMSIMSD Corrosion and Environmental Effects Committee Tuesday, March 4,1986 Mardi Gras 8:30a.m. Session Chairmen: R. H. Jones, Battelle Pacific Laboratories, P.O. Box 999, Richland, Washington 99352; and G. R. Smolik, EG&G Idaho, Inc., Idaho National Engineering Laboratory, P.O. Box 1625, Idaho Falls, I 83415
(8:30 a.m.) AN ASSESSMENT OF POSSIBLE SUBSTITUTES FOR CHROMIUM IN STAINLESS STEELS: J. S. Dunning, Albany Research Center, Bureau of Mines, Albany, Oregon 97321. (ABSTRACT NOT AVAILABLE)
(3:10 p.m.) EFFECTS OF UNDERCOOLING ON SOLUTE DISTRIBUTION AND MICROSTRUCTURES: G. J. Abbaschian, Dept. of Materials Science and Engineerlng,
Gainesville, FL
Uni~erslty
of Florida,
32611
After a brief review of the literature on the effects of undercooling on the solidification microstructure.
solute distribution and grain size of alloys, the recent experimental
results of solute distribution
profiles in highly undercooled binary alloys will be discussed. A prominent effect of undercool ing below the solidus is to cause solute-rich coring due to a part; tionless sol idi fication during recalescence. The extent of the solute-rich lone, however, is
considerably less than that predicted from the existing models based on isother,nal recalescence. A model for non-isothermal recalescence which also includes interfacial kinetics and curvature effects
will be given.
(8:55 a.m.) THE CORROSION RESISTANCE OF THE NEW HIGH ALUHINUH, LOW CHROHIUH CONTENT AUSTENITIC STAINLESS STEEL SUPERALLQYS. J. A. HcGurty, D. Cornish and J. Moteff.
B~N_e_k_~nti.
While the new high aluminum, low chromium content austenitic stainless steel ~uperal1oys arC' of primary interest because of
the exception31 oxidation resistance and their usefulness in air tn at least 2ROO°F, the alloys are stainless steels and have useful properties for corrosion resistance applications. The results of studies at the University of Cincinnati pf the corrosion resistancf> (If these new alloys jn boi 1 ing 65% nitric acid nre presented.
Data cover the testing of alloys in the annealed (~H. ~H. H) conditions as well as in the tIcal treated condition. The dat;] define the effect of the chromium. aluminum, ;]nd nickel contents on corrosion resistance ;]5 well as the effect of minor element additions. such as titanium and zirconium.
and cold worked
(9:20a.m.) (3:45 p.m.) CONTRIBUTION OF COARSENING TO THE ESTABLISHMENT OF GRAIN SIZE IN BULK-UNDERCOOLED Nt-Ag ALLOYS. T. Z. Kattamis, Dept. of Metallurgy, University of Connecticut. Storrs. CT 06268. The grain size of bulk-undercooled dilute Ni-Ag alloy specimens was studied versus initial undercooling, average cooling rate and solute concentration. Initial undercoolings varied between 20 and 250K, cooling rates between 0.14 and 6K/s and silver content between 1 and 3wt%. The grain size .of dendritic specimens which WE're subcriticallv undercooled (6T<=l70K) was practic.ally independent of initial- undercooling, cooling rate and Ag content. In supercritically undercooled nondendritic specimens (llT>=l70K) the grain size decreased with increasing undercooling, cooling rate after recalescence and solute concentration. A coarsening model was introduced which predicts fc-r a given undercooling (220K) the effects of cooling rate and composition on grain size and specific grain boundary area. This model assumes that the crystallite size distribution at the maximum recalescence temperature at the onset of cooling can be deduced from the grain size distribution in a specimen which was undercoo1ed 220K and splat-cooled.
'The Corrosion Properties of Fe-Mn-Al Alloys ~~ih-Chi~~~, Jin-Yaw Liou and Chi-Meen Wan
Department of Materials Science and Engineerlng National Tsing Hua University Hsinchu, Taiwan, R.O.C. The corrosion properties of Fe-Mo-Al alloys with full austenite structure and with austenite and ferrite structure were investigated in various aqueous environments. TIle corrosion resistance of the alloys in synthetic sea water is comparable or even better than that of 304 stainless steel. For alloys with full austenite structure the higher A1 content and the addition of 3wt% Cr could increase their corrosion resistance. The corrosion resistances of the alloys in the acid solutions studied in this work are not satisfactory. In some solutions. a passive region was observed with the formation of non-protective film and a high level of passive current. Both the resistance to general corrosiun in various solutions used in this study and the resistance to stress corrosion cracking in synthetic sea water will be discussed.
42 TMS Annual Meeting has been investigated.
No localized corrosion occurred in an
acidified Na S0 solution at 25°C and a well-defined region of 2 4
(9:45 a.m.)
passive potential appeared in anodic polarization curve. However, immersed as-welded 9Cr-lMo in NaCl solution at 25°C
The Ha rdeni ng of Fe-Mn-A 1 All oys wi th Hydrogen Shih-Chin Chang and Jen- Tung Chan Department of Materials Science and Engineering National Tsing Hua University Hsinchu, Taiwan, R.O.C. Three Fe-30wt%Mn-8wt%Al alloys with carbon contents of 0.94, 0.45 and 0.09 wt% were electrolytically charged with hydrogen in 1 N H S0 with 1 g/~ of thiourea as the hydrogen recombination 2 4 poison. With different charging conditions, the effect of hydrogen on microhardness of these Fe-Mn-Al alloys was studied. In spite of the large scatter of knoop microhardness number (KHN) value from grain to grain, the general trend was hardening of the material with hydrogen charging. In both austenite and ferrite phases, the degree of hardening increases as the charging current density increases. No microcracks were observed even with an applied charging density as high as 800 A/m 2 .
( 10: 10 a.m.) STUDIES OF SEVERAL FE-AL AND FE-AL-MN ALLOYS.
R. Wang, School of Materials Science and Enginity of New South Wales, P,O. Box 1, Kensington, 2033, Australia. binary alloys, Fe-(1-14}Al, and ternary alloys Fe-lOAl)Mn were studied in potentiodynamic corrosion tests in IN 4' for the investigations of the passivity of these alloys. lnfluence of aluminium content on the passivity of Fe-AI base and the minimum beneficial amount of aluminium was estabThe influence of manganese content on the passivity .of base alloys and the maximum beneficial amount of rnanestablished. These alloys were also tested in a 3.5% Na
showed serious pitting attack on the heat affected zone. The meatallurgical structure of the attacked region has been examined. The effect of post weld heat treatment at various tem0 peratures ranging from 500 to 900 e on the occurrence of pitting attack has also been studied and correlated with hardness changes. Surface analysis for metal oxide films on parent metal, weld and heat affected zone, examination of metallurgical structure and electrochemical measurements have been used to explain the pitting corrosion. *This work is supported by Oak Ridge National Laboratory/Martin Marietta Energy Systems under contract No. MMES Ifl9X-27466V.
(11: 50 a.m.) CORROSION OF Fe-Mn-Al ALLOYS. A P Bentley, J W Fourie and C Altstetter*, National Institute for Materials Research, CSIR Pretona, Republi.c of South Africa. To evaluate whether Fe-Mn-Al (femnal) alloys might be chromium free stainless steels, alloys with and without Si and C additions were corrosion tested in 1N H,SO" 3,5% NaC1 solution, tap water and a ground water which simulates that in a gold mine. Results from potentiodynamic polarization scans and from immersion testing are compared with those for austenitic and ferritic stainless steels and for mild steel. Though the femnals have a tendency toward passive behavior in some of the media, the current density is unacceptably high compared with true stainless steels. In both the potentiodynamic scans and immersion tests the femnal alloys were similar to mild steel, except that they showed a greater tendency for pitting. The alloys tested could not be considered as substitutes for conventional stainless steels in applications requiring good corrosion resistance. On leave from University of Illinois at Urbana - Champaign.
PASSIVE FILM FORMATION OF NONMAGNETIC Cr-Mn-N STAINLESS STEELS IN CHLORIDE-CONTAINING ENVIRONMENT: H.G. Chun, Z. Eliezer and H.L. Marcus, Department of Mechanical Engineering, Center for Materials Science and Engineering, The University of Texas, ·Austin, Texas 78712. Nonmagnetic Cr-Mn-N stainless steel has been widely used as a substitute of austenitic Cr-Ni stainless steel. The nature and formation of passive film in the two different series of Cr-Mn-N alloys (l8Cr-18Mn-N and 18Cr-13Mn-2Ni -N) have been investigated in several chloride-containing environments. Pass i ve fil mana 1ys is with Auger electron spectroscopy, Secondary ion mass spectroscopy and X-ray photoelectron spectroscopy was performed to study in-depth composition and the chemical state of each alloying element in the film. In-situ study of film formation with ellipsometry combined with potentiostatic technique was also performed to measure the film thickness and to study the kinetics of film formation. This research was supported by the Office of Naval under contract no. N00014-83-K-0143.
Research
( 11: 00 a.m.) CORROSION BEHAVIOR OF CANDIDATE CONTAINER MATERIALS IN GRANDE RONDE BASALT GROUNDWATER: R. P. Anantatmula and R. L. Fish, Rockwell Hanford Operations, P.O. Box 800, 1135 Jadwin, Richland, WA 99352. Three candidate waste package container materials, viz., AISI 1020 cast and wrought low-carbon steel, Cupronickel 90-10, and Fe9CrlMo steel were tested for 5 months at 2000C in Hanford Grande Ronde Basalt groundwater (9.75 pH) under anoxic conditions «0.1 mg/L dissolved oxygen in water). Testing was performed in 1 1 iter titan i um autoc 1 aves at a pressure of 1000 ps i and a fl ow rate of --0.02 ml/min. The average corrosion rates at 200 0 C were 0.9 "m/yr for Cupronickel 90-10 and Fe9CrlMo steel, 1.1 "m/yr for cast low-carbon steel and 1.4 "m/yr for wrought low-carbon steel. Pitting was not detected in any of the specimens. Based on the present investigations, all the materials exhibit excellent corrosion behavior under anoxic conditions. However, long-term tests under conditions simulating all the possible repos i tory envi ronments are needed before the fi na 1 contai ner material selection.
(11: 25 a. m. ) EFFECT OF POST WELD HEAT TREATMENT ON CORROSION OF MODIFIED 9Cr-
IMo FERRITIC STEEL: In-Tak Nam, Yang Ki Hong and Paul D.P. Spear, Materials Engineering Program, Department of Mechanical Engineering, Auburn University, Auburn, Alabama 36849. Pitting corrosion of as-welded modified 9Cr-lMo ferritic steel
ALUMINA AND BAUXITE III Sponsored by TMS Light Metals Committee Pontchartrain Ballroom A Tuesday, March 4, 1986 Sheraton Hotel 8:30a.m. Session Chairman: Dr. Y. Yetman, Reynolds Metal Company, P.O. Box 9911, Corpus Christi, Texas 78469
(8:30 a.m.) PIJIGUAOS BAUXITE TREATMENT IN A LOW TEMPERATURE DIGESTION PLANT: S. A. Escalona and C. Suarez, Interalumina, Pto. Ordaz, Venezuela, and J. M. Gomez, Bauxiven, Caracas, Venezuela This paper presents a sununary of the geoloqy of the Pij iguaos bauxi te and main characterist ics of mining and transportation operations. Fr0rn the noint of view of chemical and mineral0gical analysis, the Pijiguaos bauxite can be considered metal grade bauxite with the following average composition; alumina as trihydrate 50, 0%, total si 1ica 10,6%, reactive si 1ica 2,1% and iron oxide 11,5%. Pilot plant and laboratory test work shows that small modifications, mainly related to the quartz and low reactive silica content, are required to process this bauxite in a low digestion temperature ~lant. An estimate of raw material and energy consumptions shows that i lis comparable to others trihydrated bauxites.
(9:00 a.m.) MODEL FOR HANDLING PROPERTIES OF ALUMINA BASED ON PARTICLE CHARACTERISTICS: H. P. Hsieh, Aluminum Company of America, ,~lcoa Technical Center, Alcoa Center, PA 5ize and shape distributions of alumina particles are known to affect the bulk handling properties. Three bulk handling properties have been modeled: angle of spatula, compressibility, and flow time. The effects of size distribution and shape on those properties are accounted for in a Mooney-type model containing a packi ng factor and a shape term represented by a Fouri er morphological descriptor called radance. In addition, nonmechanical particle-particle interactions are incorporated in the model by a simp 1 ifi ed empi ri ca 1 form. The mode 1 predi ct s the compress i bi 1ity very well and provides reasonably accurate estimates for the flow time and the angle of spatula. It shows that an alumina with a larger size median or a smaller packing factor or a larger radance will be easier to handle. Results from the model, confirmed by data strictly from correlations, indicate that particle-particle interactions contribute greatly to the handling propert i es wi th the rema i ni ng 20-25% cont ri but i on from the size distribution effect and 5-15% contribution from the shape effect.
TMS Annual Meeting 43
(9:30 a.m.) MUL TIPOINT ALUMINA POT HOPPERS FEEDING IN ALUMINIUM SMELTER BY POTENTIAL FLUIDIZATION CONVEYING SYSTEM: J. P. Hanrot, Aluminium Pech ey, Engineering Department 13.120 GARDANNE, France. TIle patented AI.DfiNILM PEOlINEY process of contirua.Ls fluidized alumina f~ of electrolysis pot-line utilise the peculistities of fluidizable poio
CARBON TECHNOLOGY III Sponsored by the TMS Light Metals Committee Tuesday, March 4, 1986 Pontchartrain Ballroom C Sheraton Hotel 8:30 a.m. Session Chairman: Jean-Paul Huni, Alcan International Limited, P.O. Box 1250, Jonquiere, Quebec, Cana-da G7S 4K8
(8:30 a.m.) INFLUENCE OF ANODE BAKING TEt1PERATURE Atle CURRENT DENSITY UPON CARBON SLOUGHING: Euel R. Cutshall, Reynclds Metals Conpny, P.O. Box 1200, Listerhl11 (Shetheld), Alabama 35660.
(10:15 a.m.) FUNDAMENTAL CHOICES IN THE FIELD OF ENERGY SAVING IN AN ALUMINA PLANT: A.Teodosi, C.Amorino, G.Murenu, Eurallurnina SpA Portoscuso leA), Italy
In an existing Bayer process plant for alumina production, having the digestion unit with direct live steam injection in the liquor and production of a certain amount of mechanical energy via steam turbine drivers, several improvements in the field of energy saving have been done in relation to the dramatic increase of the energy cost. Having a certain margin in the pumping of the ma~n flow the evaporation rate was increasingly reduced and correspon-
dingly the steam distribution significantly changed. The excess steam vented from digestion Was dedicated to alternative usage, other than evaporation.
Plant-size anodes werE used to detern,ine the influence of baking temperature (942 and 1095 0C) and operat i ng current dens ity (0.6 to 1.8 amp/cm 2 ). Our results indicate that anode baking tenperature is much more influential than operating ccrrEnt density. Poorly baked anodes (-9500C) tend to slough more carbcn into HE elect ro 1yte than we 11 baked (-llOOOC) anodes. No uniform trend for sloughing was observe at current densities of 0.6,0.8, 1.0 all" 1.3 amp/cm 2 . Our results support the pub"ished evidence that electrolytically generated C02 is forced up through the i nteri or of the anode and reacts most prcb,bly with the bindo' coke according to the Bo,,douard Reactior. However, this work shm"s that thE Boudouard Reactior is n'Jt the mechanism responsible for the majority of slough carbon generat ion. The majority of the carbNI sloughed from anodes originates frw the sides of the anodes, below bath level, operating at vuy 10>1 current densities.
The production of mechanical energy by
steam turbines became less attractive, generating in some case a situation of furced production and utilization of the low pressure steam. The history of the energy saving in Eurallumina plant is presented, with the present and future situation.
(10:45 a.m.) ALCOA PRESSURE CALCINATION PROCESS FOR ALUMINA: S.W. Sucech & C. Misra, Alumina & Chemicals Division, Alcoa Technical Center, Alcoa Center, PA 15069 A new alumina calcination process developed at Alcoa Technical Center is described. Alumina is calcined in two stages. In the first stage alumina hydrate is heated indirectly to 500°C in a decomposer vessel. Released water is recovered as process steam at 110 psig pressure. Partial transformation of gibbsite to boehmite occurs under hydrothermal conditions of the decomposer. The product from the decomposer containing about 5% LOI is then calcined by direct heating to 850°C to obtain smelting grade alumina. The final produ t is highly attrition resistant, has a surface area of 50-80 m /g and a LOI of less than 1%. Account i ng for the recovered steam, the effecti ve fuel consumption for the new calcination process is only 1.6 GJ/t A1 0 . 2 3
(9:00 a.m.) A r1ETHOD AND INSTRUMENT FOR AUTO~1ATIC MEASUREMENT OF ANODE SLU~IPING: G.R. Romovacek, J.H. Buxton, F .J. Pascoe: Koppers Company, Inc., 440 College Park Drive, ~lonroeville, PA 15146; R. Barclay, P.G. Campbell, Jr., Alumax of South Carolina, ,tit. Holly Plant, Goose Creek, SC 29445. A system has been designed to measure slumping in anodes manufac tured for the aluminum industry. The non-contact system can resolve measurements to within .007 inches. Its components include a sonar devi ce, el ectromechani ca 1 scanner, pul se wi dth detector and sing 1e board computer. Pu 1 ses, whose wi dth determi nes exact di stance, are recei ved from the sonar devi ce as it scans the anode surface. The input is filtered to remove extraneous values and compared to stored specifications. If an anode is out of spec, an alarm is energized. Data from each anode is buffered and can be transferred to another computer for entry into a hi stori ca 1 database. Thi s i nformat i on wi 11 be used to i nst itute controls and provi de graphi c representation. The commercial application of the method and instrument was used for the inspect i on of carbon anodes produced inA 1umax plant of South Carolina. T:le results of this testing are presented.
2
(9:30 a.m.) ANODE BAKE FURNACE CONTROL SYSTEM: J. S. Berry, Jr. and A. C. Hu: Reyno 1ds Metals Company, Reduct i on Laboratory, [ 1 sterhi 11 ,Alabama. In 1978, a project for reducing fuel consumption and flue maintenance was i nit i ated. One furnace was ret rofitted and operated for about one year with a prototype control system which control s two fires (1 preheat and 1 heat section). Data on temperature, emi ssions, and fuel consumption rates were collected to develop an algorithm to opt i mi ze furnace operat ions.
(11:15 a.m.) BIOMASS UTILIZATION IN THE DRYING PROCESS:
J.P.M.
Franco,
Mineracao Rio do Norte, S.A., Porto Trombetas, Oriximina, PA, Bras i I In February 1985, a pioneer bauxite drying system went on stream to dry Minerar;.ao Rio do Norte's Amazon bauxite. The installation consists of a wood hand! ing system and fluidized bed reactor which permits substitution of fuel oil by wood chips. This report describes the comparative operating results obtained with the utilization of wood and oil burn and indicates the measures adopted for preservation of the fauna and flora of the project1s area of influence.
The results justified the design and installation of a compLJterbased di stri buted mi croprocessor control system used for process opt i mi zat i on and contro 1, data collect ion, and report generat i on. The microprocessor units are convenient to the sensor and burner racks that must be moved peri odi ca lly. Each mi croprocessor uni t is connected to the central computer by a 'high speed bidirectional communication loop. Operation of the system thus far has yielded a more uniform product, reduced emi ss ions, ant i ci pated reduct ion in fl ue ma i ntenance, and a larger than predicted fuel savings.
(10:00 a.m.)
(11 :40 a.m.)
ALUMINA YIELD IN THE BAYER PROCESS: 661,65.000 Sao Luis, MA, Brasil
R. den Hond, Alumar, Caixa Postal
Abstract Not Available
COMPARATIVE STUDY OF A VERTICAL VS HORIZONTAL FLUE RING FURNACE THROUGH ENERGY AUDIT: R. T. Sui and T. Bourgeois: Universite du Quebec, Chicoutimi. Quebec, Canada; R.D. Peterson, R. Coulombe, A.L. Proulx: Alcan Smelters and Chemicals Ltd., Jonquiere,Quebec, Canada. A heat bal ance for a VFRF is worked out and compared with that of a HFRF, both of Alcan Smelters and Chemicals Ltd., Jonquiere, QC.~
44 TMS Annual Meeting
Canada. The control volume covers the heating and preheating zones but excludes the cool i ng zone. I t was observed that (1) air represents an important energy gain for the VFRF but not for the HFRF, (2) the heat losses to the foundation and to the atmosphere are hi gher in the VFRF than in the HFRF, (3) bri ckwork is 1arge heat si nk for the HFRF and even more so for the VFRF, (4) packing coke combustion is a heat source more important in the VFRF than in the HFRF, (5) volatiles combustion is a heat source less important in the VFRF than in the HFRF. The heat balance is a good tool for highlighting the distinct features of each of the two types of ring furnace, for analyzing the process and for identifying possible avenues for its improvement.
(10:30 a.m.) EFFECTS OF ANODE CURRENT AND ALUMINA-COVER THICKNESS ON THE TEMPERATURE AT THE BIMETAL JOINT IN ANODE ROD/SPADE ASSEMBLY: Nouri Levy and Jan Lablans, Alcan International Limited, Kingston, Ontario, Canada K7L 4Z4. A study of the effects of anode current level and al umina cover thickness on temperature at the interface of the steel/aluminum bimetal joint in an anode rod/spade assembly is presented. gh temperatures at the bimetall ic joint must be avoided sin.ce could lead to rapid deterioration of the mechanical pere of the joint. In this study, a finite element electric model of the anode is used to calculate average ture at the joint for a range of values of anode urrent, alumina cover thickness and carbon block height. It s shown that the temperature at the joint varies as the square the anode current. It increases and becomes more sensitive variation in the anode current as the alumina cover thickincrease·s. The temperature is not very sensitive to block height. Results are shown graphically and are rized in a single formula with anode current as a variable the a 1umi na cover thi ckness as a parameter.
TED ANODE CLEANING: Joe Rieg, Intalco Aluminum Corporation, Fernda 1e, WA 98248 tomated anode cleaning has been developed at Intalco for eaning multi-pin anodes. The anodes consist of three blocks th two pins in each block. The top surface of the anode is elevated around each pin socket and the entire anode is mantled with an aluminum spray. The resulting anode assembly is efficient; however, it has proven to be difficult to clean manually. Cleaning is now accomplished utilizing pneumatic hammers mounted to independent positioning mechanisms controlled by an electronic programable controller. Benefits realized from the cleaning equipment include a reduction in employee exposure to vibrating equipment, the ability to remove increasingly stronger bath and the ability to handle larger quantities of bath.
CAST SHOP TECHNOLOGY AND RECYCLING III: Metal Treatment Sponsosred by the TMS Light Metals Committee Tuesday, March 4, 1986 Pontchartrain Ballroom B 8:30a.m. Sheraton Hotel Session Chairman: C. E. Eckert, Alcoa Laboratories, Alcoa Center, PA 15069
(8:30 a.m.) MINT® -- AN IN-LINE MELT PURIFICATION SYSTEM: PREDICTING COMMERCIAL PERFORMANCE WITH ALUMINUM ALLOYS: Joseph A. Clumpner,
Covenant College, Lookout Mountain, TN 37350, James E. Dare, Ceramic Foam Filter Division, Consolidated Aluminum Corporation, 205 Main Street, Hendersonville, NC 28739 MINT® is a melt in-line treatment process which was developed to remove soluble and insoluble impurities from molten aluminum during transfer between furnace and casting station. Several unique features make:the MIN1!lsystem particularly suitable for providing high quality metal for a variety of semi-continuous casting processes. Corrunercial experience has demonstrated the MINT® system is effective in removing hydrogen, sodium, lithium and non-metallic inclusions from aluminum alloy melts over a wide range of alloy composition and operating conditions. Mathematical equations may be used to predict the performance during normal operations.
(9:00 a.m.) THE MULTICAST™ FILTRATION SYSTEM: D. V. Neff, Metaullics Systems, 31935 Aurora Road, Solon, Ohio 44139, E. P. Stankiewicz, Metaullics Systems, 31935 Aurora Road, Solon, Otloio 44139. Multicast™ is a new filter media configuration designed to permit conttnuous or multiple batch filter usage, with significant cost savings. In addition, this system, employs rigidly bonded ceramic media which appears to offer superior filtration efficiency compared to ceramic foams. The system consists of a carefully engineered filter media assembly housed in a heated vessel, configured for variousTM10w rate and casting pit size requirements. The Multicast System has been used in aluminum cast houses for nearly one year with excellent operating personnel acceptance, metal quality, and substantial cost ~Mfectiveness compared with other filtration means. Multicast is also applicable to the casting of zinc and zinc alloy.
(9:30 a.m.) DEEP BED FILTRATION-THEORY INCLUDING HYDRODYNAMIC AND INERTIAL EFFECTS COMPARED WITH EXPERIMENTS: To A. Engh, B. Rasch, The Norwegian Institute of Technology, Department of Metallurgy, N-7034 Trondheim, Norway; E. Bathen, SINTEF, N-7034 Trondheim, Norway. A review is presented of the efficiency of collection of granul ar-bed fil ters due to di ffusion and di rect interception. It applies to both aerosols in gases and particles and dissolved elements in liquids (metals). Furthermore, it is pointed out that inertial impaction and hydrodynamic effects can become important. Finally, a general formula is given for the efficiency of collection of particles from liquids in a granular bed which includes diffusion, interception, hydrodynamic effects and inert i a 1 impact ion. The proposed theory gives reasonable correspondence with published results on aerosol removal in granular beds. Also it explains published results concerning the removal of titanium borides from aluminum melts to an alumina ball bed, and our own results using graphite sampling filters to study removal in ceramic open pore filters (Selee). The graphite filters and Selee filters were cut, and the deposition profile of inclusions was studied metallographically.
(10:00 a.m.) A COMPUTER MODEL OF A STIRRED TANK REACTOR IN TRACE ALKALINE ELEMENTS REMOVAL FROM ALUMINUM MELT - THE ALCOA 622 PROCESS: Judy Gubala, Ingot Casting Division, Alcoa Laboratories, Alcoa Center, pA 15069, Ho Yu, Ingot Casting Division, Alcoa Laboratories, Alcoa Center, PA 15069. It is often desirable to remove trace alkaline elements from the aluminum melt prior to ingot casting. A common method for remova 1 is by di spers i ng a gaseous mi xture of argon and ch 1ori ne through the a1umi num melt ina stirred tank reactor. A batch Al coa 622 uni t was used to study the react i on rate contro 11 i ng mechanisms in the reactor. Kinetic and reaction gas surface area data were correlated, and a computer model of the Al coa 622 Process was created. The computer model has been used in design, parametric study, and optimization of the Alcoa 622 Process.
(10:30 a.m.) FILTRATION EFFICIENCY OF INDUSTRIAL FILTERS FOR MOLTEN METAL TREATMENT: A FILTRATION MODEL EVALUATION - P. Netter, Centre de Recherches Cegedur Pechiney BP 27 38340 Voreppe and C. Conti, Faculte Poly technique de Mons, 7000 Mons (Belgium). --------
The many practical uncertainties in evaluating metal cleanliness make comparison between efficiency of liquid aluminium filtration processes difficult. Mathematical modelling, therefore, is an aid to compare, design and control of the operation of deep bed filters for molten metal. We have compared initial filter performances of commercially available filter media in manufacturers recommended velocities range by means of mathematical modelling. This study implies previous characterization of structural properties : elementary filtration cells, porosity, flow properties. These mOdels, although sometimes complex, cannot account for the heterogeneous nature of suspensions and gJranular ftilter material as well as complex flow patterns through filter media. One has to plug practical information in the mathematical models to make them useful.
(11:00 a.m.)
APPLICATION OF SPEC IF IC CAKE RESISTANCE VALUES TO FILTER SELECTION IN THE INGOT PLANT: M. Scherbak, P.O. Box 150, Massena, NY 13662; C. E. Eckert, Aluminum Company of Prnerica, Alcoa Center, PA 15069; R. E. Miller, Aluminum Company of Prnerica, Alcoa Center, PA 15069; D. Apelian and R. Mutharasan, Drexel University, School of Engineering. Correctly sized cake mode filters used in the Ingot Plant
result in acceptable metal qual ity at minimum operating costs while avoiding excessive a1uminostatic head losses. The parameter necessary to perform filter size calculations is the overall cake resi stance, (aa), which has been shown to be a function of alloy type, inclusion morphology, and pre-filter meta 1 qual i ty. In thi s paper, an extens i on of the authors' previously developed technique is used to measure (aa) values in 2011 and 2014 alloys in the Ingot P1 ant. A desc ri pt i on of the apparatus used, data manipulation, and filter size calculations resulting from actual (aa) values collected is given.
(11 :30 a.m.) THE ASV INLINE SYSTEM FOR REFINING OF ALUMINUM: E. Myrbostad, T. Pedersen ASV Metallurgical R&D Center, N-6601 Sunnda 1 soera, Norway and K. Venas SINTEF, Dept. of Metallurgy, N-7034 TrondheimNTH, Norway. Arda1 adn Sunnda1 Verk a.s has the last 3 years, in cooperation with SINTEF in Trondheim, developed a system for purifying 1 iquid metals. The system has so far been tried mainly in aluminum, both as an in1 ine system and as a batch system. The system is based on a patented rotor system, and a patented heating system is an important part which gives new possibilities in secondary aluminum foundries, and also in ferroalloy, steel and copper industry. The rotor gives a very good gas distribution and a smooth surface, and has a favourable form with respect to erosion. The new ASV heating system is a part of the rotor system. This means freedom in selecting the lining materials, and still keep the possibilities to heat the melt when fluxing. 2 complete systems are today tested in production at the ASV plants. The experi ence so far is promi sing wi th respect to qua 1ity and costs. Analyses shows that the removal of hydrogen, sodium, calcium, oxides and carbides is the same or better then other comparable systems today.
COPPER, NICKEL, COBALT & PRECIOUS METALS III: INNOVATIONS IN PRECIOUS METALS PROCESSES A Sponsored by the TMS Copper-Nickel-Cobalt & Precious Metals Committee Tuesday, March 4,1986 La Galerie 5 Mariott Hotel 8:30 a.m. Session Chairman: S. D. Hill, U.S. Bureau of Mines, Salt Lake City Research Center, 729 Arapeen Drive, Salt Lake City, UT 84108
(8:30 a.m.) EFFECT OF FOREIGN IONS ON LEACHING OF GOLD WITH THIOUREA: B. Pesic, University of Idaho, College of Mines, Moscow, 10 ~
The effect of various cations and anions on dissolution of gold with thiourea was studied. These are: Na+, K+, C1-, N01, soi , Pb 2+, Fe 2+, Fe 3+, S2-, Zn 2+, Cu Z+, Ni 2+, Mn2+, and Ca 2'. The electrochemical measurements were performed on the gold rotating disc by using the three electrode technique: pure gold disc as a working electrode, platinum counter electrode, and standard calomel electrode. The current potential curves were examined for each studied ion to evaluate the standard kinetic parameters. It was found that the majority of the studied ions didn't have any effect on dissolution of gold. Among detrimental ions, cupric ion was the worst.
(9:30 a.m.)
TMS Annual Meeting 45
INCREASING THE AMENABILITY OF GOLD ORES FOR THIOUREA LEACHING: Dr. R. Schulze, SKW Trotsber9, FGR In the past several years, considerable interest has been shown in using thiourea for leaching precious metal-bearing ores. However, reagent consumption is usually high and passivation of the thiourea solution occurs due to detrimental interactions of the thiourea with certain mineral species. SKW recently recommended addition of SO, to enhance thiourea leaching; however, more recent experimental work has shown that other reagent addit ions are even more effect i ve. Detrimental interactions can be overcome by addition of spec i ally deve loped reagents, thus improv i ng both go 1d extraction and reducing reagent consumption. Examples are given for both oxide and sulfide ores for pure thiourea and modified thiourea leach solutions. These reagent additions increased gold extraction from 85 to 95 pct and reduced thiourea consumption from 3-5 kg/t to less than 1.5 kg/t.
(10: 15 ".m.) ACID PRESSURE OXIDATION OF PRECIOUS METAL BEARING SULFIDE CONCENTRATES: Ph i 1 i P Thompson, Dawson Meta 11 urg i ca 1 Corp., 5217 Major St., Murray, UT 84107
Pressure oxidation under acid conditions offers an alternative to smelting precious metal bearing sulfide flotation concentrates. A background of various pressure ox i dat i on (autoclave) processes is presented, and the important reactions and reaction products are discussed along with practical considerations for a commercial autoclave plant. Extraction of precious metals from the autoclave residue by cyanidation is discussed, with particular emphasis on enhancement of silver extraction using a 90°C lime conditionin9 step prior to cyanidation. Results of laboratory autoc1aving and cyanidation tests on selected sulfide f1 otat i on concentrates is presented.
(10:45 a.m.) ALKALINE AUTOCLAVE PRE-CYANIDATION TREATMENT OF CARBONACEOUS GOLD RESERVES AT GOLD ACRES, NEVADA: Robert D. Osmanson, Cortez Gold Mines, Cortez, Nevada 89821. The Gold Acres Mine supplied oxide ore feed to Cortez Gold Mines from 1973 to 1976. Although the oxide portion of the deposit is exhausted, substantial tonnages of unoxidized reserves were left to challenge metallurgists to develop an economic treatment method. The carbonaceous prot ore contains 4.8 grams gold per tonne, about 1% organic carbon, and 3.5% pyrite. Extensive assay work, microscopy, and microprobe work has shown that the gold is associated submicroscopically with pyrites. Acid digestion is precluded by the high limestone/dolomite content of the resource. Alkaline autoclave pretreatment research was initiated in 1981. Recent programs have studied temperature, oxygen overpressure, autoclave time at temperature, and agitation speed for affect on extraction and operating cost for systems employing sodium carbonate to the autoclave, sodium hydroxide to the autoclave, and no reagent addition to the autoclave. Testwork results are presented.
(9:00 a.m.) RECOVERY OF SILVER, GOLD, AND LEAD FROM A COMPLEX SULFIDE ORE WITH FERRIC CHLORIDE, THIOUREA, AND BRINE LEACH: Richard Sandberg, U.S. Bureau of Mines, 729 Arapeen Drive-;-saTtLake City, UT 84108
(11:15 a.m.) THE RECOVERY OF GOLO FROM UNCLARIFIED PREGNANT SOLUTIONS BY USE OF ACTIVATED CARBON IN A MULTISTAGE COLUMN: A. Mehmet, W.A.M. te Rie1e, and D.W. Boydell, Council for Mineral Technology, Randburg, South Africa
The Bureau of Mines investigated a hydrometallurgica1 procedure to recover go 1d, silver and byproduct 1ead from a complex lead-zinc sulfide ore. A ferric chloride pre leach pxtracted about 50 pct of the zinc and formed insoluble silver and lead chlorides at 40° C in 6 h; subsequent acid thiourea 1eachi ng extracted about s-5 pct of the gold and s i 1ver in 1 to 3 h at 40° C. Lead chloride was solubilized from the remaining residue with 55° C NaC1 brine solution in 1 h. Lead metal was recovered from the brine solution in an anion selective membrane electrolytic cell at a current efficiency of 95 pct and a current density of 100 Aim'. Spent ferric chloride leach solution was reoxidized in the anode compartment at a current efficiency between 75 and 95 pct.
The feasibility of using activated carbon in a multistage column (NIMCIX contactor) for the recovery of gold from unclarified pregnant solutions was investigated on pilot-plant scale. It was found that satisfactory extraction can be achieved, yielding an average gold concentration of 0,0077 p.p.m. in the barrens from a feed having an average gold content of 1,89 p.p.m., corresponding to a recovery of 99,6 per cent. The results show that excessive loading of CaCo, can be prevented by lowering the pH of the feed to about 7.6, thereby e1 iminating the need to treat the carbon with HC1 solution. The carbon was eluted by the Zadra procedure. The operating conditions of the e1ution-e1ectrowinning circuit are reported, and the elution of gold and other metals is discussed.
46 TMS Annual Meeting
DEFORMATION II TMS-AIME General Abstract Session Tuesday, March 4, 1986 Mardi Gras A-B Marriott Hotel 8:30m a.m. Session Chairman: Anil K. Sachdev, Metallurgy Dept., General Motors Research Labs., Warren, M148090-9056
(8:30 a.m.) SHEAR STRAIN LOCALIZATION IN HIGH STRENGTH STEEL: J. G. Cowie, M. Azrin, and G. B. Olson, Army Materials and Mechanics Research Center, 405 Arsenal St., Watertown, MA, 02172-2719. The causes of shear instability in high-strength martensitic steels were studied using both dynamic and quasistatic loading
conditions. Constitutive flow relations were measured from torsion and linear shear tests, with and without normal loads. The thin-wall torsion test provides the .. behavior in pure shear, while the linear shear allows testing with higher superimposed compressive An unexpected result of these tests is that the strain for shear localization in 4340 steel is identical isothermal (quasistatic) and adiabatic (dynamic) loading itions. Therefore, high strain-rate thermal softening s appear relat i vely unimportant to strain localization in dness steels. Shear-compression combined loading tests pressure-dependent instability strain. In addition, microscopy reveals void formation at carbide particles rly stage of strain localization. Void softening effects ed with carbides therefore appear as the dominant cause strain localization and eventual shear fracture.
and growth of voids in dual phase steel sheet, were investigated. Steel containing 0.08 C, 1.45 Mn and 0.21 Si was cold rolled 50% and intercritically annealed. Changes in strain state (i.e. neck geometry) were produced by varying widths of constant thickness tensile specimens. A transition from diffuse to diffuse plus localized necking, as well as a decrease in post uniform elongation, occurred with increasing MVF or specimen width. Void size and density in the necked region increased toward the fracture surface in specimens exhibiting localized necking. However, voids were nucleated uniformly, regardless of necking behavior. Void nucleation sites (related to the martensite) and differences in void size and density will be discussed relative to the effects of constraint on void growth. This work was supported by the Metallurgy Program, Division of Materials Research, National Science Foundation. (9:50 a.m.) MICROSTRUCTURAL AND STRAIN RATE EFFECTS IN DUAL PHASE STEELS: M. S. Nagorka, D. K. Matlock, and G. Krauss, Colorado School of Mines, Golden, Colorado, 80401.
This study examines the effect of strain rate on the strain hardening behavior in dual phase steels containing O.OBC, 1.45Mn, and 0.21Si and processed with various starting microstructures. Normalized, martensitic, and as cold rolled specimens were intercritically annealed at 717°C for 5 minutes. These specimens and ferrite-spheroidized carbide specimens were tested in tension at three strain rates; strain hardening data were then evaluated. For each microstructure strain hardening rates at high strains decreased (while uniform and post uniform elongation increased) with increasing strain rate. The initially martensitic microstructure exhibited the lowest strain hardening rates at strains above 0.07. Strain rate sensitivity, strain hardening behavior, and strain gradients in the necked regions of the specimens will be discussed relative to martensite particle size and distribution and compared to strain hardening theories. This research was funded by the Metallurgy Program, Division of Materials Research, National Science Foundation.
(10: 10 a.m.)
r'L.r~HHjG C1o' l!'IEi:: GH.1'.IN '/<75 ALLOY: T. rfsu~uku. 'l'llkahashi. Mitsubishi :-J:eavy Industries,Ltd., :-i:~d lI. Y'):-:;hiC:A., Ur.0, ;Jll:r.i tomn LiGht f·lr.tal Indugtry ,Ltd., hagoya, Japan
grain refinement process and the .superplastic characteristics '€' .studied en 7475 a'_uminuPl alloy. The thermo['lechanical process includi!1g furr:ace cooline from solution temperature, which results i!i a ooderatr.: di3persio::. of precipitate particles, has been (~stablished for grain refinement of 7175 alur.::tinuffi alloy. Ji t~ this therr.wmcchanical procet;s, grain si:~e of the order of lO)lffi or less has been achievpd. The su:perplastic characteristics of the !Ylatf'rial l!1ade 'by the process Here e\aluHted by trn:>ile nnd bulcp. fr'IT'd!1G b>:] ts. The' resul"':5 can be ':;'.l:::.1f.lRri :-::8d RG fol~(w3. The rlutcrial shmi:3 v"Ory hieh m-value3 (""'0.8) a!1d low 3treSGCJ (U.l ::gyrIllrr10r les.') at strain-rat€' of 1.0 x lO'''''scc· ' ct !jOOoe. In thi3 condition, -'c}:0 ITl.'lteria.l eloneated mOT'G than 600 %. 'i'lw cavity after :::;uJ1prp2.nstic dcforGlaticm ';"us Llnalyzed by i:;JQ(3'e 8Ylalyzer l':\l1d it ,'iUS ShO',\D tlw.t tne r.avi ty formation ;oJas influrnced r.:ainly by the crn:;-:, :;i.~e. b:!l!lpcJ"aturc and strain-rate.
(9: 10 a.m.) INVERSE DUCTILITY AND LOW TEMPERATURE MECHANICAL BEHAVIOR OF AUSTENITIC Fe/Mn/Al/Cu/Si/Nb/C STEEL FOR CRYOGENIC MATERIAL: Young G. Kim, Jae K. Han, Dept. of Materials Sci. & Eng., Korea Advanced Institute of Sci. & Tech., Box 131, Chongryang, Seoul, Korea, Yee S. Park, Sammi Speciality Steel Co. Res. Lab., Changwon. Korea, Tae H. Kwon, Pohang Iron and Steel Co., Res. Lab., Pohang, Korea.
The behavior of increasing elongation with decreasing temperature was observed in the austenitic Fe/30Mn/SA1/O.4Cu/O.2Si/O.lNb/O.3C steel. The air melted ingots were processed by hot controlled rolling processes for grain size refinement and dislocation substructural strengthenings. The steel exhibited 47% elongation at -196°C, compared with 20% elongation at room temperature. The steel also displayed very high strengthes: the yield strength of the steel at -196°C was 956 Mpa, while that at room temperature was 630 Mpa. The Charpy impact energy of the steel at -196°C was 125 J, which is about twice that of the conunercial 9%Ni steel. This paper presents potentials of the controlled rolled steel for cryogenic structural materials.
STRESS RELAXATION OF WC-Co, Gwendo1y~~, Roger N. Wright Materials Engineering Department, Rensselaer Polytechnic Institute, Troy, NY 12181.
I
Stress relaxation tests on commercial cemented carbide tools were performed under stress and temperature conditions similar to those found at the tool-chip interface during a typical metal cutting operation. Elevated temperature elastic modulus measurements have been made as well. The elastic measurements and stress-relaxation data are useful to develop stress-strainstrain rate-temperature relationships suitable for manufacturing process modelling and relevant to the wear process. Tests have been performed in the 800 to lOOOoC range and stress relaxation has involved strain rates ranging from 10- 7 / s to 10-4/ s . A series of materials has been evaluated involving grain sizes of 1, 2, and 3 ~m and cobalt contents of 3, la, and 13 w/o. Quantitative analyses of Co distribution have been performed. Implications regarding service performance and process modelling will be discussed.
(10:30 a.m.) BIAXIAL TENSION TESTS or HERF 304L STAINLESS STEEL:* D. A. Hughes, Sandia National Laboratories, Livermore, CA. Yield anisotropy of high strength (690 MPa) High Energy Rate Forged (HERF) 304L stainless steel was investigated via biaxial loadiny experiments. Biaxial tensile tests with proportional 10adi ng were performed on thi n-walled tubu1 ar specimens usi ng internal pressure and axial load. Results of these tests reveal eo signif1cant yield strength anisotropy in the forgings. As a consequence, traditional isotropic yield criteria, such as tile von Mises or Tresca theories, were not representative of the forged strengths. These observed yield trends are interpreted in light of the forming operation and resultant microstructure. TEM of the forgi ngs reveal ed a heterogeneous d1 sl ocati on substructure whi ch inc 1uded elongated sUbgrai n formati on para 11 e 1 to the forgi ng di recti on. This di sl ocati on substructure provi des evi dence of inhomo~eneous deformati on duri ng the forgi ng process, and the creation of internal stresses. Yield anistropy is thought to arise in large measure from the 1nterna·1 stress distribution. *Thi s work supported by U. S. Department of Energy, DOE, under Contract Number DE-ACUQ-7bDPU0789.
(10:50 a.m.) (9:30a.m.) THE EFFECTS OF STRAIN STATE ON VOID GROWTH DURING TENSILE TESTING OF DUAL PHASE STEELS, D.L. Steinbrunner, O.K. Matlock, and G. Krauss, Colorado School of Mines, Golden, Colorado 80401.
INTERNAL AND EFFECTIVE STRESSES IN THE STEADY-STATE CREEP OF POLYCRYSTALLINE CADMIUM AT ROOM TEMPERATURE: Derek O. Northwood* and Ian O. Smith+, *Dept. of Engg. Mats., University of Windsor, Windsor, Onto N9B 3P4, Canada; + Dept. of Mining & Metallurgical Engg., University of Queensland, St. Lucia, Queensland 4067, Australia.
The effects of martensite volume fraction (MVF) and strain state on necking behavior, post uniform elongation, and the nucleation
High-purity polycrystalline cadmium was creep tested in air at room temperature and the streSS-dip test used to determine the
TMS Annual Meeting 47 effective (a e ) and internal (oi) stresses. The stress-exponent of steady state creep was 2.24 for applied creeT) stresses, a, less than about 14 MPa but increased to 6.1 at higher stresses, indicating a possible change in rate controlling mechanism. The internal stress varied with the applied stress, a, increasing with increasing o. ai/a ratios remained constant at 0.93 to 0.98 and did not change at the high a values where the stress exponent of steady state creep had indicated a change in rate controlling mechanism. ai/a ratios of 0.9-1.0 agree with previous data for pure metals.
(11: 10 a.m.) CYCLIC STRAIN EFFECTS IN PURE ALUMINUM AT 4.2 K by K. T. Hartwig and Guansen Yuan, App1 ied Superconductivity Center, University of Wisconsin-Madison, 1500 Johnson Dr., Mad i son, WI 53706. Pure aluminum is used in the composite superconductors proposed for large scale magnetic energy storage for the electric utility industry. The conductors in these storage magnets will be subjected to low level cyclic stress; the pure aluminum component will undergo electrical and mechanical changes with time as crystal defects build up. Such property changes must be known for conductor design and to predict operating characteristics. Aluminum covering the purity range 99.995 to 99.9997% was given uniaxial cyclic strain to 0.5% at 4.2 K while monitoring stress versus strain and electrical resistivity. Strength saturates after about 1000 cycles independent of the strain level and the maximum stress at equilibrium approaches £E/2 where £ is strain range and E the e1asti, modulus. The effect of impurities is to aid the cyclic hardenl ng process.
(11 :30 a.m.) THE CYCLIC STRESS-STRAIN BEHAVIOR OF A SINGLE CRYSTAL NICKElBASE SUPERAllOY AT AN INTERMEDIATE TEMPERATURE, T. P. Gabb, NASA lewis Research Center, Cleveland, OH 44135 and G. E. Welsch, Professor, Department of Metallurgy & Materials Science, Case Western Reserve University, Cleveland, OH 44106. The monotonic plastic flow behavior of several single crystal nickel-base superalloys has been shown to vary significantly with crystallographic orientation. In the present study, the cyclic plastic 610w response of one such alloy, PWA 1480, was examined at 650 C in air~ Single crystal specimens aligned near the [001], [all], [Ill], and [123] crystallographic directions were tested in fully reversed, tota1-straincontrolled low cycle fatigue tests at a frequency of 0.1 Hz. The cyclic stress-strain response and general cyclic hardening behavior will be analyzed as a function of crystallographic orientation and initial plastic strain range.
EARL R. PARKER SYMPOSIUM ON STRUCTURE/ PROPERTY RELATIONSHIPS: MICROSTRUCTURE AND MECHANICAL PROPERTIES III Sponsored by The Mechanical Metallurgy, Structural Materials and Physical Metallurgy Committees oj TMS-AIME Tuesday, March 4, 1986 Mardi Gras D 8:30a.m. Marriott Hotel Session Chairmen: Govind R. Chanani, Aircraft Division, Northrop Corporation, 1 Northrop Avenue, 3872/62, Hawthorne, California 90250; William W. Gerberich, Department of Chemical Engineering and Materials Science, University of Minnesota, Minneapolis, Minnesota 55455
(8:30 a.m.) ENHANCED SUPERPLASTICITY IN ALUMINUM AND TITANIUM ALLOYS:
(9:00 a.m.) DEFORMATION BEHAVIOR OF SILICON SINGLE CRYSTALS: S. Mahajan
Carnegie-Mellon University, Department of Metallurgical Engineering and Materials Science, Pittsburgh, PA. The Czochralski (eZ) silicon single crystals constitute a model material to assess the influence of the density of mobile dislocations on yield drops and the formation of Hiders bands. In this study. the as-grown and aged (eZ) crystals oriented for single slip have been deformed at 800°C. It is observed that the yield drop is progressively reduced on aging and is absent in crystals containing a high density of aging-induced dislocat ions. Also, the Liiders front lies normal to the activated slip vector. Arguments for rationalizing these observations will be presented.
(9: 30 a.m.) STRUCTURAL ANALYSIS OF SOLIDS FOR ALLOY DESIGN: HIGH RESOLUTION ANALYTICAL ELECTRON MICROSCOPY: R. W. Carpenter, Ctr. tor Solid State Sci., Arizona St. Univ., Tempe, AZ 85287
Structural analysis for alloy design purposes has been significantly advanced during the last decade by the development of analytical electron microscopy. The method permits determination of local composition and, in some cases, local chemical bonding structure in solids without appreciable sacrifice at image resolution. The best results are obtained when tield emission electron guns are used. The methods will be illustrated with applications to metal matrix composites and electronic materials.
(10:00 a.m.) THE CHARACTERISTICS OF MICROSTRUCTURES IN ALUMINUM ANNEALED AFTER IMPLANTATION WITH SELECTED MOLYBDENUM CONCENTRATIONS, ~.~,
Benson, Jr., North Carolina State University, Raleigh, S. Army Construction Engineering Research Laboratory, Champaign, IL, J. Bentley, Oak Ridge National Laboratory, Oak Ridge, TN. The microstructures in aluminum annealed after implantation with selected concentrations of molybdenum were examined using analytical electron microscopy techniques. The BCC phase Al12Mo was isolated as the only second phase structure in the molybdenum range considered. The morphology of the Al12Mo in this molybdenun concentration range can be controlled by selecting the maximum as implanted molybdenum concentration. A predominantly lamellar Al12Mo structure formed initially in the surface modified region when aluminum was annealed after implantation with molybdenum to maximum concentrations in the range of 3.3 to 4.4 atomic percent (a/a). A model was developed that is consistent with the experimental orientation relationship and with the observed interface planes. A continuous film of All2Mo formed in the surface modified region when aluminum was annealed after implantation wi th maximum molybdenum concentrations in the range of 8.0 to 11.4 a/o. ~r.-D:- Stephenson, U.
(10:30 a.m.) THE EFFECT OF MATERIAL PROPERTIES ON EROSION BEHAVIOR: Alan ~ Materials & Molecular Research Division,
Lawrence Berkeley Laboratory, University of California Mail Stop 62/203, Berkeley, CA
94720
Erosion of ductile, structural metals by small, solid particle impacts is a high strain rate, large strain mechanism that occurs on a micro scale. The effects of materials properties measured on macro-size specimens on this severe, micro deformation process will be discussed. Erosion occurs in many dev ic es tha t operate ate levat ed tempera t ures and the eros ion process itself generates elevated temperatures on the metal surface. The nature and behavior of the corrosion scales that form on alloys at elevated temperatures are greatly affected by the impacting particles. The effects of the scale forming properties of metals on their combined erosion-corrosion behavior will also be discussed.
J. A. Wert, Dept. of Materials Science, University of Virginia, Charlottesville, VA
22901.
Constitutive models are available to describe thp relationship between stress and strain rate for deformation mechanisms that contribute to superplasticity. These models enable us to identify microstructural and compositional changes needed to provide superplasticity at higher strain rates or lower tempp.ratures. In heat treatable aluminum alloys, reduction of grain size is the primary means for improving superplastic properties. The required grain size control has been acheived through development of thermomechanical processing methods. In dupley titanium alloys, grain size, phase ratio and diffusivity can all be controlled to enhance superplasticlty. Alloy modifications to Ti-6Al-4V have heen used to demonstrate these effects. Spom::ored by AFOSR and Rockwell International.
(11 :00 a.m.) BASIC CONCEPTS IN Ni BASE SUPERALLOY DESIGN:
S. M. Copley,
University of Southern California, Los Angeles, CA 90089-0241 Although their chemistry is complex, the structure of Ni base superalloys is relatively straightforward. The diversity in superalloy compositions suggests considerable flexibility in alloying to achieve desired properties. This paper considers the interrelationships of composition, processing, microstructure and properties of Ni base superalloys with particular emphasis on factors affecting morphological stability, bulk strengthening, and grain boundaries.
48 TMS Annual Meeting
(10:15 a.m.)
EXPERIMENTAL METHODS FOR MICROGRA VITY MA TERIALS SCIENCE RESEARCH III Sponsored by the ASMIMSD Thermodynamic Data Committee Tuesday, March 4,1986 Mardi Gras C 8:30 a.m. Marriott Hotel Chairman: R. A. Schiffman, Midwest Research Institute, Kansas City, Missouri 641 IO Session Chair: D. M. Stefanescu, Department of Metallurgical Engineering, University of Alabama, University, Alabama 35486
(8:30 a.m.)
,.
PROCESSING IN EARTH-ORBIT Hendrick, and M.J. Martin, Rockwell
M.D.
Lind,
International
nd Oaks and Downey, CA.
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th-orbit, floating-zone processes can be applied to a r variety of materials, and the melted zones can be larger than is possible in the gravitational field at rthls surface. Furthermore, there wi 11 be no natural ticn in the melt in earth-orbit. However, convection sed by surface tension gradients may be expected. We conducting a series of space-flight experiments to investifloating-zone processes in earth-orbit and evaluate the potential of these processes. As subjects for our first experiments we have chosen In and Se, because their low melting points and low vapor pressures simplify the apparatus. Floating-zone processes are not practical for either of these elements on the earth because of their low ratios of surface tension to density. We expect to extend these experiments to her elements, compounds, and solid solutions eventually. is paper wi 11 discuss our experimental methods, fl ight rdware, and supporting ground-based experimentation.
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(10:35 a.m.) POSITIVE EFFECTS OF LOW GRAVITY ON FINE DISPERSIONS OF AiZ03 PARTICLES IN THE Ai MATRIX AFTER MELTING AND SOLIDIFICATION (Experiment ES 311 Performed aboard SPACELAB 1).
F. Barbieri, R. Berti, P. Gondi and C. Patuelli The influence of low gravity on the microstructure of S.A.P. (Sintered Aluminum Powder) with Al203 particles in 4% and 7% weight concentration were examined by transmission and scanning electron microscopy as well as by microhardness tests. These examinations allowed mechanisms to be postulated from the microstructural features of dispersed particles. Moreover, with regard to the experimental methods,some of the structures observed made it possible to determine the direction of melting or of solidification. Both )..lg-specimens showed a fine distribution leading to a very uniform hardness. In particular, 7% S.A.P. specimens exhibited a considerable strengthening with hardness twice that of pure aluminum and 25% greater than that of the reference samples. The same fine distribution of A1203 particles of connnercial S.A.P. may be obtained by melting specimens in O-g. The 1-g reference samples showed a high agglomeration degree of AlZ03 particles and a highly non-uniform microhardness since on Earth the particles can be aggregated in the mel t as they flow or sink because of buoyancy.
(11 :00 a.m.)
ISOTHERMAL DENDRITE GROWTH SPACE EXPERIMENT AND APPARATUS: Edward A. Winsa, NASA Lewis Research Center, Cleveland, Ohio, Marten E. Glicksman and Richard C. Hahn, Rensselaer Polytechnic Institute, Troy, New York . The NASA Lewis Research Center is designing and building an apparatus for the study of dendrite growth kinetics and morphology in the microgravity environment of the Space Shuttle. The first experiment flow" will measure the growth velocity and tip radii of succinonitrile (a transparent crystalline material) dendrites as a function of supercool i ng (di fference between sol idus temperature and actual solidification temperature). The experiment data will be compared to theoretical predictions and data from extensive ground based tests conducted at the Rensselaer Polytechnic Institute. Key engineering challenges in the automated apparatus include photography of dendrites with micrometer level resolution and isothermal temperature control within a few milliKelvin of the setpoint.
. CRYSTALS ON SPACELAB 3
L. Kroes and D. Reiss, Space Science Laboratory, NASA Marshall pace Flight center, Huntsville, AL 35812 R. B. Lal, Department of Physics and Applied Physics, Alabama A&M University, Huntsville, AL 35762 An experiment to study the growth of single crystals of triglycine sulfate (TGS) was successfully carried out on Space1ab 3. The objectives of this experiment were: (1) to develop a technique for solution crystal growth in a low-g environment, (2) to characterize the growth environment and determine its influence on growth behavior, and (3) to determine how the low-g growth environment influences the properties of the resulting TGS crystals. Two crystals were grown from seeded solutions and hundreds of holographic photographs taken of the solution/crystal interaction during the growth process.
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(9:25 a.m.) EXPERIMENTAL FACILITIES AND PROJECTS FOR MICROGRAVITY MATERIALS SCIENCE WITHIN THE GERMAN SPACE PROGRAM: G. Feuerherdt, Dr. P. Vits MBB/ERNO Bremen, Germany. -----For performing microgravity research on SPACELAB, the sounding rocket program TEXUS, and the so-called MAUS program us i ng NASA get away speci a 1 conta i ners on Shutt 1e missions, MBB/ERNO has developed a growing inventory of experiment facilities, such as furnaces for materials processi ng experiments, vari ous process chambers for instance for fluid physics experiments, and diagnostic tools such as real time television systems. These experiment and support facilities will in the future also be made available on a commercial basis to researchers and laboratories worldwide. The MAUS and TEXUS programs, all owi ng experimenters to conduct valuable research with rather modest expenditures, are being conducted in preparation of more ambitious programs being performed on SPACELAB missions and in the future also on free-flying platfonns like EURECA.
(9:50 a.m.) EXPERIMENTAL FACILITIES FOR FLUIDS IN SPACE A. Gonfalone, ESA/ESTEC, Noordwijk. Several lnstruments are being developed by the European Space Agency in the frame at its Mi crogravity Programme to study fluids in a microgravitational environment. Descriptions of the Improved Fluid Physics Module, the Bubble and Drop Unit and the Critical Point Facility are given. The latest performance of the Fluid Physics Module flown on the German Spacelab 01 Mission is presented. Emphasis is placed on the stimulil diagnostic techniques. A brief comparison with non-ESA facilities concludes the paper.
(11 :25 a.m.)
INFLUENCE OF OXIDE PARTICLE NUCLEATION ON WELD METAL SOLIDIFICATION IN MICRO-GRAVITY: M. Nance and J. E. Jones, Colorado School of Mines, Center for Weldinq Research, Golden, CO 80401 Electron beam welds were made on a rotating disc in the M512 apparatus in Skylab. The welds were made on three materials: 2219-T87 aluminum, 304 stainless steel, and rure tantalum. The welds in each material exhibited differences in solidified microstructure between the Skylab samples and ground based samples welded under identical conditions. The primary difference observed was a finer, more equiaxed, grain structure in the Skylab welds. This study used a carbon replica method with transmission electron microscopy to characterize the oxide particle distribution in the welds. The oxide particles in the Skylab samples exhibited less agglomeration and weld surface accumulation. Thus, the fine grain structure is likely due to fine, well dispersed oxide particles which act as grain nucleation sites. The fine dispersion results from the lack of convective currents which would cause the agglomeration and lack of buoyancy which would cause particle surface accumulation of the oxide particles.
EXPERIMENTAL TECHNIQUES IN HIGH TEMPERA TURE SCIENCE III Sponsored by the ASMIMSD Thermodynamic Data Committee Tuesday, March 4,1986 Mardi Gras F-G 8:30 a.m. Marriott Hotel Chairman: R. A. Schiffman, Midwest Research Institute, Kansas City, Missouri 651 10 Session Chair: R. E. Spjut, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
(8:30 a.m.) APPARATUS FOR HIGH TEMPERATURE ELECTRICAL CONDUCTI VITY MEASUREMENTS OF HIGH VAPOR PRESSURE MATERIALS: *F.R. Szafran
and H.W. Parker, Space Science Laboratory, NASA Marshall Space Flight Center, HuntSVille, AL The eddy current technique of electrical conductivity measurement is frequently used at temperatures slightly above
TMS Annual Meeting 49 ambient or lower. We have extended the technique to 1000° by using ceramic coil fonners and high temperature alloy wire. The samples (which include mercury cOlllpounds) must be contained in heavy-walled ampules which reduces the filling factor. The low filling factor combined with the relatively high resistance alloys which must be used for the coils produce a reduced signal-to-noise ratio compared to the normal applications of this technique. The present state of electronic instrumentation nonetheless permits useful measureluents to be made on materials that cannot be measured any other way because of their high vapor pressures. The apparatus will be described in detail and data obtained on solid and liquid HgTe (m.p. 670 C) will be presented. *wotK supported by NASA Microgravity Science and Applications Division.
high pressure combustion or steam environments combined with simul taneous phase characterizat ion using laser Raman spectroscopy. Specimen heating is obtained with a computercontrolled 275 Watt cw CO 2 laser. Power densities of 8xl0 4 W/cm 2 and heating rates of 1000 K/s have been achieved. OxidRtion of Zr and SiC and the phase stability of Zr02 as a function of temperature have been studied. The oxidation kinetics of Zr were obtained from 1573 K to 2673 K in steam and steam-hydrogen environments. Oxidation of SiC in simulated combustion environments has been observed with a video system from 1773 K to 2223 f at 1.5 atmospheres. *Work is supportf'd by the U. S. Nuclear Regulatory Commission under Contract DE-AC06-76RLO 1830 NRC FIN-B?455
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(9:00 a.m.) THE PROBLEMS OF ATTAINING EQUILIBRIUM WITH REFRACTORY MATERIALS: Leo Brewer, Lawrence Berkeley Laboratory and Department of Chemistry, University of California, Berkeley, CA. The tight binding of atoms in refractory compounds often makes it difficult to attain equilibrium with the bulk of the sample, particularly when the temperature limit of the experimental technique is limited to relatively low temperatures of lSOOK or less. As temperature is increased, equilibration between the bulk and surface of the sample becomes more rapid, but there is also an acceleration of various deteriorative effects such as reaction with the container, conversion to an electronic conductor of a cell electrolyte, etc. One must extend the possible operating temperature range by catalyzing the equilibration of the sample while restraining the deterioration of the experimental technique. Methods of dealing with this problem will be discussed for experimental techniques involved in (1) determining phase diagrams of solid phases, (2) determining thermodynamic properties using solid electrolyte cells, and (3) determining vapor pressures.
AUGER SPECTROSCOPY AND OPTICAL IMAGE ENHANCEMENT TECHNIQUES APPLIED TO THE SURFACE OXIDATIOI~ REACTION OF H20 VAPOUR WITH LIQUID URANIUll* Will iam r·lcLean II, .igbert Siekhaus, Ed Schmitt, Lawrence Li vennore I~atl onal Laboratory, Li vennore, CA 94550 Uranium surfaces, cleaned in-situ by argon ion bombardment, were exposed at several temperatures above the melting point, 1150 C, 1170 C, 1200 C, to water vapour }ntroduced i gto a UHV vacuum chamber to pressures from 1 x 10- to 5 x 10- Torr. The increase in the surface's oxygen concentration was measured by Auger spectroscopy as a function of water vapour exposure. The appearance of the first oxide island and the growth of the oxide island on the surface was measured as a function of exposure by a video camera observing the surface through an optical microscope. The video images were analyzed using computer controlled video image enhancement techniques. The results are compared with present surface segregation, surface growth, and thennal emi ssivity theories. *Work perfo,"ned under the auspices of the U. S. Department of Energy by the Lawrence Li vennore Nati onal Laboratory under contract number W-7405-EtlG-48.
(9:25 a.m.) HIGH TENPERATURE STUDIES WITII CO
2
LASER IIEATED SAPPHIRE:
H.Abrevaya, Signal Research Center Inc, 50 East Algonquin Road, Hox 5016, Des Plaines, II 60017; and P. C. Nordine, Midwest Research Institute, 1~25 Volker Blvd., K.ansas City, ~10 6/1110. CO Laser heating of thin filarnental sajlphire specimens were used 2 in a low pressure flow reactor in order to study evaporation and chlorination of single crystal and liquid aluminas. A sapflhire specimen which partly melts as a result of one sided transverse laser heating does not melt through due to a higher emittance for the liquid than for the solid and allows simultaneous reactivity studies of the two phases. Heasurements of liquid and solid AL,03 evaporation rates give results which are consistent with other investigators who used different techniques. Evaporation measurements were also done under conditions where rates are retarded by the presence of a laq~e gas phase saturation or by the presence of oxygen. Sapphire specimens develop a hexagonal prism shape after reaction with chlorine containing gases, whereas evaporation does not change tile initially cylindrical specimen shape. It is concluded that chlorination of Al 0 is a structure sensitive reac2 3 tion, while evaporation is mosely isotropic.
(11 :25 a.m.) DETERMINATION OF THE MOLECULAR STRUCTURES OF THE ALKALI HALIDE MONOMERS AND DINERS BY ELECTRON DIFFRACTION: M. Fink, and
*
J. Hartley, Physics Department, The University of Texas, Austin,
TX The electron diffraction patterns of the alkali halide vapors have been recorded. Fourier analysis led to the molecular struccures of the monomers, the dimers and a coarse indication of the relative concentrations. The monomer bond lengths agree with previous micro-wave data. The dimers are rhombi wi th the apex angle at the alkali changing continuously from larger than 90 0 to less than 90 0 as a function of the ionic radius of the alkali. The bond lengths increase from monomer to dimer, however they remain far short of the values in the crystal. The mean amplitudes of vibration were fixed to the previous estimates of Welch and his coworkers. The monomer-dimer ra t ios disagree signi f icantly with the predictions derived from the JANAF tables.
*
This work was supported by the NSF fiCHE 8307174
(9:50 a.m.) USE OF SOLID GALVANIC CELLS FOR OXYGEN DIFFUSION MEASUREMENTS AT HIGH TEMPERATURES:* J-W. Park and C. Altstetter, University of Illinois at Urbana - Champaign. Electrochemical measurements have been carried out on both BCC and FCC metals and alloys to detennine the diffusion co-efficient of oxygen. The exact experimental method must be adapted to the characteristics of the system under study. In particular, the solid solubility of oxygen and its vapor pressure are critical parameters. Techniques will be discussed using both zirconia and thoria-based electrolytes over the temperature range 923 - 1673K under ul tra-hi gh vacuum conditi ons. With some methods both diffusivity and solubility values may be detennined in the same experiment. Results for pure nickel, palladium, niobium and vanadium and Nb-V alloys will be used to illustrate the methods. This work was supported by the Department of Energy through the Materials Research Laboratory of the University of Illinois.
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(10:35 a.m.) GASEOUS CORROSION OF MATERiALS AT HIGH TEMPERATURES WITH TIMERESOLVED SIMULTANEOUS LASH RAMAN SPECTROSCOPY: Charles H.
*
Henager, Jr., G.J. Exarhos, and Laboratory, Richland, WA 99352
J.T.
Prater,
Pacific Northwest
In-situ corrosion and phase transformation studies have been conducted with a system capable of high temperature simulation of
EXTRACTIVE AND PROCESS METALLURGY TMS-AIME General Abstract Session Tuesday, March 4, 1986 La Galerie 2 8:30a.m. Marriott Hotel Session Chairman: John Pusateri, St. Joe Mineral Corp., Technical Center, Monaca, PA 15061
(8:30 a.m.) DEVELOPMENT OF NEW METHOD TO PRODUCE BORON-SILICON CONTAINING
AHORPHOUS MELTS: R. C. Sussman and L. G. Evans, Armco Inc. Research & Technology, 703 Curtis Street, Middletown, Ohio
J
45043.
Research work has been completed on the development of a new patented process for the melting and refining of a boron containing alloy. Based on theoretical postulations, experiments were performed on 1000-pound heats. On this basis, a new ref ining process was developed, which employs convent ional steelmaking vessels for using steel scrap, ferro alloys and boron ores to produce an FeSiB alloy. The process can eliminate the need for ferro boron alloy, high purity iron and remelt stock to produce the amorphous alloy. Process variables were established and consistent results achieved to produce the alloy with lower tramp levels than typical FeSiB melts. This process should greatly reduce the liquid metal costs for producing such an alloy for the production of amorphous boron containing steel.
50 TMS Annual Meeting
(8:50 a.m.) SEGREGATION ROASTING & BENIFICATION STUDIES OF DEEP SEA NODULES: B. K. Parekh, Institute for Mining & Minerals Res., University of Kentucky, Lexington, KY 40512, W. M. Goldberger, Superior Graphite Co., Chicago, IL 60606 and T. L. B. Jepsen, C. E. Basic Inc., Gabbs, NV. Segregation roast study of fine groWld ocean ncxiules were conduct ed in presence of a carl:onaceous reductant and a chlorinating agent which was a mixture of sodium chloride and calcium carl:onate or calcium hydroxide. The rrost effec:tive roasting temperature was fOtll1d to be above 850OC, where rrost of the Ni, Cu, and Co elffiE1ts present in the nodules migrated to the carbonaceous reductant. It was also found that roasting of ground nodules mixed with middlings, obtained from previous tests I provided a high magnetic concentrate, obtained using a low intensity rragnetic separator, averaging 23.7% Ni, 12.4% CU and 4.6% Co. Recovery (ooncentrate and middlings combined) of Ni, Cu and Co averaged greater than 90 percent. Electron scanning micrograph of the concentrate indicated. it to be an alloy of Ni, eu, Co, and Fe metals.
UPGRADING CQ.IESTIC TITANIUM: Dae S. Kim, Yong U. Choi and Suk J. 1m, KIER 219-5 Garibong, Guro Gu, Seoul, Korea. Titaniferrous slags containing about 60% Ti02 were successfully produced by smelting the domestic titaniferrous magnetite ore containing a1x:lut 20% TiO?_ and impurities such as iron, rragnesium and calcium. To rerrove the impurities present in the slags, the ground slags were treated with gaseous mixture of S02 and 02' A series of tests were conducted to investigate the effect ·of temperature, time and particle size on the impurity removal. The treated slags were then leached with hydrochloric acid at pH of 2.0 to dissolve the sulfated impurity compounds in the slag. Ti02 content in the slag with particle size of about 200 mesh was upgraded to more than 90% when sulfated at 800 0 C for 2 hrs with and equal' volume of S02 and 02' folloloJed by an acid leaching.
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the resu I ts pred i cted by the mathemati ca I mode I of a ball i ng drum circuit developed by Cross. The laboratory technique was the same uti I ized by Sastry at the Uni versity of Berkeley and the results indicate that the Cross digital simulation can be improved if we modify the second-stage of the ball growth kinetics by including the effects of feed rate and hold-up.
(10:30 a.m.) Application of Computer System at Hachinohe Works: H. Osaka M. Moriya, F. Tarmo. Hachinohe Works, Hachinohe Smelting Co. ,Ltd. Japan Hachinohe Works are engaged in zinc and lead smelting by ISP (Imperial Smelting Process). We have systematically utilized process computers, a business computer, and personal computers for the purpose of saving energy, reducing labor cost, and better overall operation. The process computer system, which was upgraded since 1980, is composed of five terminal computers and a system control computer. The business computer, introduced in 1968 and upgraded since 1985, is used for office management and tectmical calculations. Our first personal computer "las introduced in 1983. We have expanded this system to six machines that perform individual office business. Our constant upgrading of the computer system has allowed a higher degree of mutual data exchange resul ting in more efficient plant operation. This paper shows about the following: (1) Outline of the canputer system (2) Development history of the canputer system (3) Computer control system func tions and interrelationships (4) Future plant for the computer system.
(10:50 a.m.) REMOVAL OF ARSENIC FROM LEAD SMELTER SPEISS: M. R. Peterson and L. G. Twidwell, Department of Metallurgy and Mineral Processing Engineering, Montana College of Mineral Science and Techno logy, Butte, MT 59701. Experimental studies have been conducted that demonstrate that elemental arsenic can be effectively volatilized from sulfur containing lead smelter speiss in carbon monoxide atmospheres. Volatilization data will be presented. Impurity transport will be di scussed.
A METHOD FOR THE PRODUCTION OF FLUXED PELLETS USING PEAT MOSS
AS A BINDER: B.C. Jena, S. C. Panigrahy, M. Rigaud, Ecole Polytechnique, University of Montreal, Montreal(P.Q.), Canada; and A. Lemay,Centre de Recherches Minerales, Ministere de l'Energie et des Ressources, Sainte-Foy(P.Q.), Canada One of the major difficulties encounterd in the production of fluxed pellets is their stickiness during the process of induration. A method has been developed to overcome this problem by addition of peat moSS during the green balling stage. A network of pores left behind by the burning of peat moss during induration, holds the liquid phase by capillary action and thus helps to minimize the stickiness. The extra porosity created through peat moSS addition also has been found to improve pellet reducibility.
(11: 10 a.m.) IMPROVED ZINC MARKETABILITY THROUGH NEW PRODUCTS AND PROCESSING TECHNOLOGY: Etsuji Nomura, K. Kikuta, and H. Kubo, Mitsui Mining and Smelting Co., Ltd., 2-Chome, Nihonbashi-Muromachi, Chuo-Ku Tokyo, Japan. Mitsui Mining and Smelting Co., Ltd. has two zinc smelters, Kamioka and Hikoshima, and other two, Miike and Hachinohe, which belong to its subsidiaries. They consist of two electrolYSiS, one ISP and one vertical retort process and their
total zinc production was 225,000 t/y in 1984.
(9:50a.m.) Pickling of Annealed 304 Stainless Steel: B. S. Covino. Jr., T. J. Driscoll, J. P. Carter, and P. M. Fabis, Avondale Research Center, Avondale, MD 20782 The U.S. Bureau of Mines has investigated the pickling of stainless steels by studying the dissolution behavior of 304 stainless steel and three alloys representat ive of the chromiumdepleted region. Tests were conducted as a function of nitric and hydrofluoric acid concentrat ion from 30° to 90° C with added Fe, Cr, and Ni salts. Dissolution rates for all four alloys increased linearly with HF concentration, followed a non-linear relationship that exhibited a maximum with nitric acid concentration, and followed an Arrhenius-type behavior with temperature. Added metal salts caused decreases in dissolut ion rate that were proportional to the metal cation's ability to complex the fluoride ion. Analyses of the nonprotective film formed on the pickled alloys in solution showed no evidence of fluoride ion penetration. The results suggest that a solution composed of 0.8M HN0 3 plus O.sM at 50° C would be optimal for pickling anneafe-d 304 stainless steel.
In the falling
zinc market following the first oil crisis in 1973, they have been making efforts to keep and strengthen their economical competitiveness according to their situation. For example, zinc alloys, zinc powder, and zinc chemicals are produced, which add to the value of zinc. Heat recovery and on-site power generation are developed. Instead of zinc concentrates, cheap raw materials like steel dusts and zinc drosses are fed to vertical retort processes.
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TIME-TEMPERATtJRE-REDUCTION DIAGRAMS OF IR ON .l\GGLOMERATES K. Cizcan, Dept. of Metallurgical Eng. ,ITU,Istanbul/furl
duction experiments has been conbined and represented in TTR-Diagrams for temporarily constant cO/c02/N2-gas mixtures between 300 Oc and the melting temperature. The double logarithmic reduction function over the transformed time and temperature axes shows a pyrism-like body with four mantleplanes starting at the melting point of the unreduced sample. The gradients of three planes in
the direction of the temperature axis conform to the activation energies of the chemical reaction of wustite with carbonmonoxide by presence of metallic iron, of the
(10: 10 a.m.) COMPARISON BETWEEN EXPERIMENTAL RESULTS OBTAINED BY LOCKED CYCLE TECHNIQUE IN A BALLING DRUM AND THE CROSS' MATHEMATICAL MODEL: P. A. Young and J. Martins-CETEC, Av. Jose Candido de Si I ver Ra, 2000, Belo Horizonte-MG, BRAZIL The purpose of the work is to make a compari son between the experimenta I resu I ts obta i ned in laboratory ba II i ng drum and
diffusion of iron ions in wustite and of the gas diffu-
sion, respectively. The activation energies seem not to be affected by increasing the basicity and the carbon-
monoxide concentration, but the three planes are lifted logarithmicallY to higher reduction degrees. The fourth plane illustrates the dependence of the melting point on the reduction d~qree at the meltinq temperature. "ThlS work was supported by N~TO Res~arch Funds.
TMS Annual Meeting 51
HIGH TEMPERATURE ALLOYS III: Alternative Materials to Conventional Ni-Base Superalloys Sponsored by the TMS High Temperature Alloys Committee Tuesday, March 4, 1986 Acadia 8:30 a.m. Marriott Hotel Session Chairmen: D. L. Anton, United Technologies Research Center, East Hartford, CT 06108; K. A. Green, Allison Gas Turbine Division, Indianapolis, IN 46206
Bg~~~i ~~~d H~f~i ~~n~a~i ~i~~;)l w~~m~~u~i~~e a~l ~6bo~ N~~~! a~l ~n
~~~i~~ ~~~~~~ c~~~~~~ ~;~a~~c~e~~;~e~r6~n~~~~t ~R~8i}~tI~~e
test) to the maximun stress value (statiC creep test). The resulting $-N curve, dynamic creep curves, detailed strain responses and fractographic observations are compared wi th existing conventional nickel-base superalloys. It is found, for example, that for superalloys, this mode of testing results in $-N curves thatinvert at intermediate and high temperatures, wi th the degree of inversion being controlled by the relative impact of creep or fatigue behavior.
u~a~~s g~~~~YM~~~a sf~Q~~~~~4g: ~~~ ~~~g~o~mg~~\~ag~~~:niU.
The Garrett Turbine Engine Company generously provided the materials and technical discussion.
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GRAIN BOUNDARY ACCOMMODATION OF SLIP IN Ni3Al WITH BORON,' T.P. Weihs, E.M. Schulson, H.J. Frost, I. Baker and J. Horton+
STUDY OF SOLIDIFICATION RATE UPON DIRECTIONALLY SOLIDIFIED NICKEL ALUMINIDES*: ChOOD H. Lee, Richard Bellows, and John K. Tien, Center for Strategic Materials, Henry Krumb School of Mines, Columbia University, New York, NY 10027.
Thayer School of Engineering, Dartmouth College, Hanover, NH. +Oak Ridge National Laboratory, Oak Ridge, TN.
Earlier experiments (Schulson, Weihs, Viens and Baker, Acta Met. in press) on polycrystals of various grain sizes (3~. to lOOOum) established that the yield strength - - grain size relationship for stoichiometric Ni3A1 at 20 0 e is given by cry = Go + kd_o. 6 ±o.05 where GO and k are constants. More recent work shows that the addition of 750ppm (0.35 at.') boron does not change the a d-o. dependence, but raises 00 from 93 to 241MPa and lowers k from 2080 to l200MPa·~O.8 The latter effect leads to boroninduced weakening of the most finely grained (d
The effects of directional solidification (D. S.) on the microstructure of Ni-base aluminides are being investigated. The growth rate (R) has been varied using the Bridgeman-Stockbarger D. S. unit at Columbia to examine microstructure, porosity, segregation, and mechanical properties of D.S. Ni(3)Al. It has been found that the grain size and shape are extremely sensitiv to the variations in R. It has been also found that the genera features of creep/fatigue behavior is characterized from the viewpoint of D.S. structure. Hot Isostatic Pressing (HIP) technique will be applied to study and achieve pore closure without subsequent recrystallization. Segregation and microstructure before and after the mechanical test will be examined under scanning and transmission electron microscopes. *This work is sponsored by Oak Ridge National Laboratory under the contract Mrtta 19X-89664C and monitored by Dr. C. T. Liu.
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IN-SITU STRAINING OF Ni3Al IN THE TEM: I.Baker and E.M. Schulson, Thayer School of Engineering, Dartmouth College, Hanover, NH, and J.A. Horton. Metals and Ceramics Division, Oak Ridge National Laboratory J Oak Ridge, TN. In-situ tensile straining of Ni3Al containing 750 ppm wt. boron has been performed in a Philips EM430 TEM operated at 300kV. The resulting slip, which occurs mainly ahead of an advancing crack front, has been examined. Slip is observed to be very planar: ABP-coupled dislocations glide in intense slip bands until they meet a grain botmdary. Observations suggest that dislocations at the head of the resulting pile-up are absorbed into the grain boundary and dissociate. These pile-ups eventually led to the initiation of slip in the adjacent grain. Superlattice-Intrinsic Stacking faults, S-ISF's, have been observed to form as debris in the wake of gliding APB-coupled dislocations. This result suggests that S-ISF's do not have to form by collision of ABP-coupled dislocations on intersecting slip systems.
DYNAMIC MODULUS MEASUREMENTS IN CoAl, FeA1 and NiA1 ALUMINIDES UP TO 1300 K*: M. R. Harmouche, J. T. Hartman, Jr. and A. Wolfenden, Mechanical Engineering Department, Texas A&M University, College Station, Texas 77843.
This work was supported by a grant from the Office of Basic Energy Sciences, Dept. of Energy, Grant No. DE-FG-02-84ER45148.
Assessments of the composition and temperature dependences of Young's modulus E for the ordered Co, Fe, and Ni-A1 intermetallic compounds using NOT are reported. It is shown that E depends slightly in a parabolic fashion on composition at any given temperature T in the composition intervals 48.48 to 55,50.87 to 60, and 47.3 to 55.94 at % Co, Fe and Ni, respectively. However, E decreases linearly with T and is described by correlations of the form E(T)=E(O)-(dE/dT)T, where 298
(9:20 a.m.) "SOLID SOLUTION STRENGTHENING OF Ni 3Al." D. M. Dimiduk, H. A. Lipsitt, Wright-Patterson AFB, OH 45433, J. C. Williams and A. W. Thompson, Carnegie-Mellon University, Pittsburgh, PA 15213. Alloys of the intenneta11ic compound Ni3A1 exhibit a range of properties which are desirable in turbine engine blade and disk materials. For several years now these materials have been the basis of alloy development efforts seeking to strengthen monolithic alloys over the range of potential use temperatures, particularly at the low temperature end of the range. A number of theories on the mechanisms of strengthening in these alloys have been proposed over the last twenty-five years. Current explanations couple existing theories on the mechanisms controll ing the mechanical behavior of Ni3A1 with descriptions of the effects of ternary element additions on the stability of the Ll2 structure. The investigations reported on here are aimed at evaluating and updating the descriptions of solution strengthening of Ni3A1 through measurements of changes in di sl ocation di ssociat ion dl stances as a funct i on of the con cent rat i on of terna ry elements. The re1 ationship between these measurements and alloy strength and stability is discussed.
(11 :00 a.m.) BZ ALUMINIDES AS ALTERNATE HIGH TEMPERATURE MATERIALS ,* K. Vedula, Department of Metallurgy and Materials Science, Case Western Reserve University, Cleveland, OH 44106 and J. Stephens, NASA-Lewis Research Center, Cleveland, OH 44135.
Alloys based on FeAl and NiAl are being investigated as part of a cooperative research program between Case Western Reserve University and NASA-Lewis Research Center, Cleveland, OH. The research effort is directed towards alloying additions to improve high temperature properties as well as low temperature ductility. A range of ternary alloys have been processed by powder metallurgy techniques. Small amounts of ternary additions of Nb, Ta, Hf, Zr and B are found to significantly improve high temperature strength of both FeAl and NiAl. High temperature compressive creep results of several of these alloys will be presented and the critical structure-property relationships will be discussed.
*
Research supported by NASA-Lewis Research Center, Cleveland, Oh.
(9:45 a.m.) CREEP/FATIGUE BEHAVIOR OF A GAMHA PRIME ALLOY: * R.S.Bellows, C.H.Lee, T.Caulfield and J.K.Tien, Center for Strategic ~:;e~~~~~'N~e~~b2~rumb School of Mines, Columbia University,
m~~;gt~~~A~n~a~e~~;~amn~n~hr~e Lrxt~g~eg~d c~e;~~~:t1gue Stress controlled tensile fatigue
beha~ior
of a directionallY
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THE EFFECT OF TERNARY ADDITIONS ON THE DUCTILITY OF B2 FeA1: D. J. Gaydosh, NASA Lewis Research Center, Cleveland, OH 44135. Extruded bars of the 82 a1uminide FeA1 were made using powder metallurgy techniques. Binary FeA1 and FeA1 with various
52 TMS Annual Meeting ternary additions were produced. The ductility of the heat treated materials as a function of temperature was determined by tensile testing. Binary FeAl alloys showed 3-5% elongation at room temperature. Preliminary results showed that ternary additions increase the temperature at which ductility appears. Fracture surface analysis was used in conjunction with the tensile results to describe the brittle to ductile transition. Fractures ranged from transgranular cleavage to ductile tearing, while little or no intergranular failure was observed. Grain size of the materials was also determined.
batch reactor and a packed-bed reactor. Experimental resul ts obtai ned from the 1eachi ng tests conducted in the batch reactor are interpreted by a mathenatical model which combines the kinetics of chalcopyrite and pyrite leaching with the pore diffusion of dissolved oxygen within the ore fragment. A mathenatical model which combines the kinetics of Chalcopyrite and pyrite leaching, oxygen diffusion within the ore fragment, and external mass transfer together with the effect of fluid flow and axial dispersion has been fonnulated and tested for the overall leaching process in the packed-bed reactor. This overall model of the process gives a very satisfactory representation of the rate of copper recovery and can provide a basis for the design of a solution-mining process. *Supported by USBM under Grants G5115494, G1134149, and G1144149.
HYDROMETALLURGICAL REACTOR DESIGN & KINETICS III Sponsored by the TMS-AIME Hydrometallurgy, Physical Chemistry, and Electrolytic Processes, and SME-AIME Chemical Processing Committees Tuesday, March 4, 1986 La Galerie 6 8:30 a.m. Marriott Hotel Chairpersons: John E. Dutrizac, Mineral Sciences horatory, CANMET, Ottawa, Ontario, Canada KIA 001; . Martins, Department of Metallurgical Engineering, ColSchool of Mines, Golden, Colorado 80401
SOLUTION: V. S. T. OF PYRITE OXIDATION IN Na C0 3 and K. Osseo-Asare, Mineral1processlng and Metallurgy , The Pennsylvania State University, University Park, PA
kinetics of pyrite oxidation in Na C0 solutions has been 2 3 tigated in a bench-scale stirred reactor, under constant of oxygen. The experimental results fit a stochastic chemically controlled reactions. This model takes into the heterogeneity of ground minerals by trea ting k, the constant of traditional kinetic models as 8 conversiondependent variable. The assumptions behind this model are supported by the magnitude of the activation energy, the inverse relationship between the rate constant and the initial particle diameter, the independence of the reaction rate with agitation and finally, the micrographs of reacted pyrite, showing pits created by localized disolution beneath the layer of amorphous oxides that partially cover the sulfides. Pyrite dissolution behaviors in Na C0 and NaOH solution. are compared and implica2 3 tions for gold extrac tion from pyri tic gold, ores are discussed. Research supported by NSF and CNPq, CAPES (Brazil
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THE KINETICS OF PRESSURE LEACHING OF CHALCOPYRITE ANIl PYRITE ffiAINS IN PRIMARY COPPER ORE BY DISSOLVED OXYGEN:* H. K. Lin, H. Y. Sohn, and M. E. Wadsv.urth, Department of f\!tallurgy and f\!tallurgical Englneerlng, University of Utah, Salt Lake City, Utah 84112-1183. The kinetics of leaching of chalcopyrite and pyrite grains in primary porphyry copper ore wi th di ssol ved oxygen have been detenni ned. Experiments were conducted in the tenperature range 75-97°C under ollYgen pressures up to 9200 kPa. The observed dependence of chalcopyrite leaching rate on oxygen concentration is explained in tenns of adsorption of the dissolved oxygen followed by electrochemical reactions. Based on this consideration, the following rate equation has been fonnulated: 1 - (1 - x)I/3 = k{[02] / (l + K[02])//2t The activation energy for k calculated from experimental data is 64 kJ/mol. This compares with the value reported in the literature ranging between 30 and 100 kJ/mol. The kinetics of pyrite leaching showed a halforder dependency on oxygen indicating the electrochemical nature of the reaction. *SuPlJOrted by USBM under Grants G5105088, G5115494, and G1124149.
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PRESSURE LEACHING OF COPPER FRO'1 PRIMARY COPPER ORE UNDER SIMULATED SOLUTION-MINING CONOITIONS:* H. K. Lin and H. Y. Sohn, Department of f\!tallurgy and f\!tallurgical Engineering, Universlty of Utah, Salt Lake City, Utah 84112-1183. The 1eachi ng of primary porphyry copper ore under ollYgen pressure expected in a solution-mining operation has been investigated by using a
(10:00 :l.m.)
BREAK
(10,30 a.m.)
HYDROLYSIS AND PRECIPITATION OF IRON DURING ACID PRESSURE LEACHING OF ZINC SULPHIDE MATERIALS: H. Arauco, F.M. DoyleGarner, Dept. Mat. Sci. & Min. Eng., University of California, Berkeley, CA 94720 . The acid pressure leaching of zinc sulphide materials is a complex process involving simultaneous dissolution of the sulphide minerals and preCipitation of iron from solution. A study is being made to determine 'the conditions needed to minimise the loss of values to the iron residue. The kinetics of both leaching and preCipitation have been studied under two different sets of condi tions, which simulate the two different stages that would be needed in a "grass roots" plant. First stage leaching has been done at various temperatures and oxygen feed rates, to determine the optimun conditions for removing excess acid and iron from solutions, and to identify the iron phases precipitated. The behaviour of these iron phases during second stage leaching, at high aCidities, has been studied. The use of alkali additions to reduce metal losses to the j arosi te in the final residue has been investigated, and the effect of these additions on the leaching kinetics is reported.
(11,00 a.m.)
MODELLING AND SUruLATION OF REACTORS FOR AN OXYGEN PRESSURE LEACHING SYSTEM: v. Papangelakis l , D. Berk 2 , G.P. Demopoulos l , 1. Metallurgical Eng. Dept., 2. Chemical Eng. Dept., McGill University, Montreal, Quebec H3A 2A7. Pressure leaching is one of the most advanced and capital intensive technologies in hydrometallurgical processing of concentrates and ores. The design and selection of the proper pressure reactor in each case is therefore a consideration of critical importance. Pressure leaching reactions can be conducted batchwise or continuously in various types of autoclaves: vertical, multi-stage horizontal, and tubular ones. In this paper simulation of the performance of different pressure reactors is made for the oxidative treatment of an auriferous arsenopyrite concentrate (three phase system). Having established the rate equation and the heat of reaction representing the pressure oxidation of arsenopyrite several chemical reactor models were used to evaluate the following reactor configurations: batch stirred reactor; continuous stirred reactor (CSTR); cascade of CSTRs; plug flow reactor (PFR). Isothermal as well as adiabatic operation of the reactors was considered.
(11:30 a.m.)
A PROCESS FOR ENRICHING CHALCOPYRITE CONCENTRATES: R. W. Bartlett, D. B. Willson, B. J. Savage, and R. J. Wesely, Anaconda Minerals Company, P.O. Box 27007, Tucson, Arizona 85726 A process for enriching primary copper concentra tes, improved over tha t previously reported, is described. I t cons is ts of hydrothermal chemical enrichment to digeni te, under 11mi ted oxidizing conditions that release iron and sulfur; followed by solid-liquid separa tion; and nota tion wi th recycle of the middling flotation product to the enrichment reactor. Secondary enrichment chemistry has been made into a practical metallurgical process for upgrading copper concentra tes to 60% grade prior to shipment to a smelter. During a pilot plant investigation at 50 kg/hr, conditions were found in which it was possible to enrich chalcopyrite grains in a one-step process by simultaneously feeding oxygen, at a rate governed by stoichiometric considerations, with concentrate into a single autoclave. Under proper conditions in a continuous process reactor, this reaction can occur rapidly and efficiently, leading to a reduction in the number and size of au toclaves and in the quan ti ty o'f oxygen required. One percent of the copper and three percent of the silver were los t.
TMS Annual Meeting 53 (9: 50 a.m.)
MICROSTRUCTURE AND PROPERTIES II TMS-AIME General Abstract Session Regent Tuesday, March 4,1986 Marriott Hotel 8:30a.m. Session Chairman: M. A. Imam, Code 6320, Naval Research Laboratory, Washington, DC 20375
(8:30 a.m.) MICROMECHANISTIC EXPRESSIONS OF CONTINUUM MICROSCALE PARAMETERS FOR STABLE CRACK GROWTH: Warren M. Garrison, Jr. and Anthony W. Thompson, Department of Metallurgical Engineering and Materials Science, Carnegie-Mellon University, Pittsburgh. PA 15213. A measure of a material I s tendency to exhibit stable crack growth is the tearing modulus. In his treatment of stable crack growth Rice has developed an expression for the tearing modulus which is a function of two microscale parameters, ~ and OCt where 0c is a critical crack opening which must be maintained a characteristic distance t ~t behind the crack tip during stable crack growth. The purpose of this talk is to propose expressions for DC and~. The proposed expressions utilize a primary particle spacing and fractographic quantities which are believed to be influenced by microstructure as well as reflecting the stressstrain history experienced during the fracture process.
(8:50 a.m.) THE INFLUENCE OF AUSTENITIZING TEMPERATURE ON THE TEARING MODULUS OF AN ULTRA HIGH STRENGTH STEEL: Kevin Handerhan and Warren M. Garrison, Jr., Department of Metallurgical Engineering and Materials Science, Carnegie-Mellon University, Pittsburgh, PA 15213. In previous work it was shown that the fracture toughness of the steel HP-9-4-20 increased with austenitizing temperature. The increase in toughness was ascribed to an increase in sulfide spacing and an increase in the extent of growth of voids nucleated at sulfides due to the dissolution of fine alloy carbides. The purpose of this work has been to determine the tearing modulus of this steel as a function of austenitizing temperature and to analyze the results in terms of changes in sulfide spacing, microstructural changes as well as parameters used to characterize the fracture surfaces.
(9:10 a.m.) IMPURITY EFFECTS ON SUSTAINED LOAD CRACKING OF 2 1/4 Cr-l Mo STEEL AT ELEVATED TEMPERATURE: J.J. Lewandowski, M.B.D. Ellis, and J.F. Knott Dept. of Metallurgy and Materials Science Univ. of Cambridge, Pembroke Street, Cambridge, U.K. CB2 3QZ Commercial purity, high purity, and phosphorus-doped versions of 2 1/4 Cr-l Mo steel have been tested under sustained load at SOOoC in vacuum to determine the element(s) responsible for high temperature brittle intergranular fracture. Heat treatments were chosen to vary the amount of phosphorus and sulfur available to segregate, while bluntly notched specimens of various root radii and flank angles were tested to vary the position and magnitude of the peak tensile stress ahead of the notch. Brittle intergranular microcracks were observed to form ahead of the blunt notches, in regions of high stress. Surface analyses by Auger, and Laser Ionization Mass Analysis (LIMA) identified the element(s) responsible for sustained load embrittlement. The effect(s) of stress on the segregation of impurity elements at 500°C will be reviewed in light of recent work. This work was supported by a NATO Postdoctoral Fellowship (JJL) and by a Case Award by British Petroleum (MEDEl.
(9:30 a.m.) EFFECT OF MULTIPLE AUSTENITIZING TREATME~ITS ON 1IT-9 STEEL'. Roger Emigh, J. W. Morris Jr., Dept. of lo~aterials Science and Mineral Eng., Lawrence Berkeley Laboratory. University of California, Berkeley CA 94720. The effect of multiple austenitizing treatments on the toughness of an Fe-12Cr-1.0Mo (HT-9) steel was studied. The resulting microstructures were characterized by their mechanical properties, precipitated carbide distribution, and floacture surface appearance. It was proposed that Ulultiple transforll.ations would refine the martensite structure and improve toughness. Optical and SEU observations revealed that the martensite packet structure was somewhat refined by a second austenite transformation. Carbon extraction replicas, examined under TEN, showed that this multiple step treatment ha& 'eliminated grain boundary carbide films seen iT. single treated specimens on prior austenite grain boundaries. The 0.2% yield strength, tensile strength and elon8atiou were relatively unchanged. but the pre-cracked Charpy absorbeu energy increased for the Multiple steIi specimens.
* This work was supported by the U. S. Deiit. of Energy under contract HDE-AC03-76SF00098.
DEVELOPMEJ:T OF PLASTIC ZONE GEOMETRY DURING FATIGUE CRACK PROPAGATION IN Fe-Si ALLOY*: Y. Biro! and Go Welsch, Dept. of Metallurgy and Materials Science; A. Chudnovsky, Dept. of Civil Engr.; and A. Moet, Dept. of Macromolecular Science, Case Western Reserve University, Cleveland, OH 44106 Fatigue crack growth kinetics at room temperature has been obtained for an Fe-2.6Si alloy at two different stress amplitudes. Significant deformat ion accompanies crack growth. Measurements of the size of the deformation zone were carried out on the surface for geometrical characterization. This zone has been found to translate, expand and change shape with crack propagation. SEM fractographic studies revealed an increasing amount of cleavage with increasing crack length. Cross sections perpendicular to crack surface were investigated for a more complete characterization of the deformation zone in the interior of the specimens.
*
Research
supported~
by NASA-Lewis Research Center.
(10:10 a.m.) ON THE FRACTURE OF AL/SIC COMPOSITES' Y. Flom and R. J. Arsenault, Metallurgical Materials Laboratory , University of Maryland, College Park, MD 20742. Discontinuously reinforced 6061 AI/SiC composite material were tested and the morphologies of the fracture surfaces were analyz using scanning electron microscopy (SEM), and scanning Auger microscopy (SAM). On the macroscale, fracture of the all tested specimens can be characterized as brittle, occurring within a narrow region of the specimen in the irmnediate vicinity of the fractur~ surfaces with very little overall plastic deformation. On the microscale, fracture surfaces consist of very fine dimples ranging from the fraction of the micron to several microns in size. It is believed that void nucleation and coalescence is the primary mechanism responsible for the fracture. Void nucleation takes place at the various small particles that are present in matrix including but not limiting to SiC particulates or whiskers The bonding between SiC and the matrix appears to be very good.
*
This research was partially supported by ONR under Contract NOOOI4-85-K-0007 and MML of the University of Maryland.
(10:30 a.m.) PROPERTY AND MICROSTRUCTURE CHARACTERIZATIONS FOR THE NOVEL 1M Al-Li-Mg-Cu-Zr ALLOY SYSTEM: D. J. Chellman and R. A. Rainen, Lockheed-California Co., Burbank, CA 91520 and A.P. Divecha and R. K. Garrett, Jr., Naval Surface Weapons Center, Silver Spring, MD 20910 Current research on 1M AI-Li-X alloys has been generally centered on the addition of intermediate Cu and low Mg solute levels to obtain optimum pro"", perty combinations. The present cooperative study between Lockheed and NSWC represents a departure from these alloy systems, by examining the quaternary alloy of nominal composition AI-2 Li-3 Mg-l Cu-0.14 Zr. Seve~ ingot metallurgy alloy variants were prepared by chill casting, homogenization, and extrusion to rectangular bar. A screening evaluation on the alloy extrusions was conducted by selected physical and mechanical property tests that inchrled chemistry, density, elastic modulus, hardness, conductivity, tensile, and fracture toughness. Aging responses as a function of temperature, time, and cold work were studied initially in order to identify candidate heat treatment conditions. Tensile elongation and fracture toughness exceeded target goals tyP\elll of conventional 2XXX Al alloys, with values of 8.0 pet. and 30.0 Ksi - in. , respectively. An improvement in the strength-toughness property combination was attributed to the optimization of Mg/Cu solute levels for a given Li addition. Optical metallography and SEM observations were documented with respect to solute content and aging treatment.
(10:50 a.m.) TENSILE BEHAVIOR OF PB-SN/CU SOUIER JOINTS: Lenora~, Darrel Frear, Jikun lim, 1. W. Morris Jr., Dept. of Materials Science. Lawrence Berkeley Laboratory, University of California. Berkeley CA, 94720. Solders of nominal 60Sn-40Pb and 9SPb-SSn were used to join Cu base plates. Additions of ternary elements such as Bi, In. Sb, and Ag to the solders were also investigated. Bulk and intermetallic joint microstructures were observed for each solder. Both 8 and 11 phases formed with the 60Sn-40Pb solder while only 8 was found on reaction with 9SPb-SSn. The solder joints were strained to fracture in tension. Solder composition, intermetallies phases present, and strain rate were correlated with tensile strength and fracture surface topography. The Cu-Sn interlletallics were found to playa dominant role in the failure of the jOints in tension. The effect of the intermetallic layer thickness. which increases with time when the solder is molten, was also studied. This work .as supported by the U. S. Dept. of Energy under contract HDE-AC03-76SF00098.
111:10 a.m.) THE EFFECT OF STRAIN RATE ON THE BAUSCHINGER EFFECT IN ALUMINIUM: A.M. Eleiche, Dept. of Engineering, The American University in Cairo. M.H. El-Kabbany, Dept. of Mechanical Design and Production, Cairo Universi ty, Egypt.
A testing rig capable of the free twisting of thin-walled tubu-
54 TMS Annual Meeting lar specimens in the forward dnd reverse direction, at the quasi-
static strain rates of 0.03, 0.05, 0.08 and 0.32 5- 1 , up values of homogeneous strains without buckling, was used the Bauschinger effect in cormnercially-pure aluminium at and 300°C. Immediately after load reversal, the rna terial
to large to study 20, 100 exhibi-
ted a region of constant stress which was found to depend, as
well as. the B.E. phenomena itself, on the amount of plastic prestrain, strain rate of reversal and deformation temperature. Various indicators are used to analyse this dependence.
(11 :30 a.m.)
(8:55 a.m.) The Experimental Measurement and Theoretical Prediction of Fluid Flow and Electrodynamic Behavior of Inductively Stirred Melts: J. L. Meyer, N. El-Kaddah, J. Szekely, *C. Vives and R. Ricou, Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, *University of Avignon, Avignon, France. Experimental measurements are reported on the induced current density, magnetic flux density, the electromagnetic force field and the velocity field in inductively stirred mercury melts, both the presence and the absence of magnetic shields. These measurements are accurately and quantitatively predicted by means of a fundamentally based mathematical representation.
THE INFLUENCE OF STRAIN RATE HISTORY AND TEMPERATURE ON THE TORSIONAL SHEAR STRENGTH OF OFHC COPPER: A.M. Eleiche, Dept. of Engineering. The American University in Cairo, Egypt.
Experiments were carried out to determine the strain-rate sensitivity of the shear flow stress of OFHC copper over the temperaturE' range -150 to 400°C. Thi n-wall ed tubul ar short spec i mens were used in a modified torsional spli t Hopkinson bar. ThE' behaviour was first measured at 10- 3 and 10 3 s-1. Tests were then carried out wi th. jumps from the low to the high rate at different strains. At constant rates, the flow stress was rate-and temperature-sensitive, and s trai n hardeni ng al ways pas i ti ve. Strai n-rate change resul ts were not consistent wi th a mechanical equation of state relating stress. strain, strain rate and temperature. At low temperatures, a fini te elastic stress increment which increases wi th increasing prestrain was observed, while at room temperature and above, the increment is very small. The subsequent flow stress rises slowly towards that required for the same strain imposed entirely at the high rate. Thus, the observed rate sensi ti vi ty in constant-rate tests appears to be caused largely by strain-rate hi story effects. rather than by the instantaneous strain rate. Apparent, as well as true, activation volumes decrease with increasing strain and increase with increasing temperature.
(9 :20 a.m.) MATHEMATICAL AND PHYSICAL MODELING OF CURRENT DISTRIBUTION IN ELECTROMETALLURGICAL CELLS CONTAINING BIPOLAR ELECTRODES WITH HOLES IN THEM: Yu-Ping Zhu and R.A. Stoehr, Dept. of Metallurgical and Materials Engineering, University of Pittsburgh, Pittsburgh, PA 15261 Bipolar electrodes allow electrometallurgical cells to be more compact and more power efficient. Holes through the bipolar electrodes can allow circulation of electrolyte between compartments, and thereby maintain a more uniform bath composition with fewer feed points. Current leakage through the holes must be minimized so that the potential advantages will not be lost due to lower current efficiency. The present work involves a comb:ination of mathematical modeling and physical measurements on model copper electrowinning cells to optimize hole placement in such electrodes. Overpotentials on the electrodes is dealt with in an effective way, and an overrelaxation method is employed to solve the discretized potential flow equations. The weight of metal deposit on the cathodic surfaces was carefully mapped and its distribution agrees well with the predicted values.
11:50 a.m) EFFECT OF HEAT TREATED BETA MATRIX YIELD STRENGTH AT CONSTANT ALPHA MICROSTRUCTURE ON THE TENSILE AND FRACTURE
,KjX J~ar~~~~~a~h8~g~k~' n~a~~ol i~6r£OJYtechniC
..... ~th coXrse an~ fl.ne W~~anstatten ex (UXl) in coarse and fine prioe B grain sizes at yield of 760-790 (A.Q.), 885 and 985 (both aged) MPa. Void tion, void growth, tensile fracture and fracture toughness studied. Void nucleation occurred at a number of different sites, sometimes at the surface, sometimes at the interior •. In coarse B/coarse ex structures void growth occurred initially along prior B grain boundaries and proceeded along twin /UX1 interfaces. In fine wa. structures void gro..... th occurred by shear in a colonies. Void growth rate, GL '" ~-f-' as slo.....est in
...
coarse B/coarse ex structures at 985 ductility did not These results are touqhness.
at 885 MPa y.s. and most rapid for coarse B MPa y.5. Because of mixed prior B gra~n size consistently increase ..... ith decreasing GL' correlated with slip behavior and fracture
This .....ork was supported by the Office of Naval Research under Contract #N-00014-84-K-010B.
MODELING IN PROCESS METALLURGY II: ELECTROMAGNETODYNAMICS OF MELTS Sponsored by the TMS Physical Chemistry Committee Mardi Gras N Tuesday, March 4,1986 Marriott Hotel 8:00a.m. Session Chairmen: T. Deb Roy, Dept. of Materials Science and Engr., The Pennsylvania State University, University Park, PA 16802; M. J. McNallan, Dept. of Civil Engineering, Mechanics and Metallurgy, University of Illinois at Chicago, P.O. Box 4348, Chicago, Illinois 60680
(9:45 a.m.) Break
(9:55 a.m.) Three Dimensional, Swirl Flows in Plasma Systems: A.H. Dilawari and J. Szekely: Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 In recent years major advances have been made in the modelling of heat and fluid flow phenomena in plasma jets. However all this work has considered two dimenSional, aXi-symmetric systems. Here we shall discuss the generalization of this approach to systems involving swirl - which tends to be the case for all practical applications. The role of swirl in modifying the heat and fluid flow phenomena will be discussed.
(10:20 a.m.) A Mathematical Model of the Electromagnetic Force Field, the Fluid Flow and Temperature Profiles in Radio Frequency (RF) Plasma Reactors, N. El-Kaddah , Dept. Met. Eng., The Univ. of Alabama, Tuscaloosa, Ala 35486 A mathematical model has been developed for the calculation of the electromagnetic force field, the fluid flow and the temperature fields in a radio frequency (RF) plasma torch. The model involves the solution of Maxwells I equations (to calculate the electromagnetic force field and Joule heating), the turbulent Navier-Stokes equations (for the plasma velocity field) and the differential thermal energy balance equation (for the temperature distribution). The computed results are found to be in good agreement with measurements reported in the literature.
(8:30 a.m.)
(10:45 a.m.)
A Technique for the Calculation of the Three Dimensional Magnetic and Fluid Flow Fields in Induction Furnaces: J. Szekely, N. El-Kaddah and J. L. Meyer, Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge,
A Mathematical Representation of Plasma - Melt Transfer in the Presence of Foaming Slags: J. McKelliget and J. Szekely, Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
MA 02139 The electromagnetic force fields and the velocity fields in induction furnaces an!d an inductively stirred ladle metallurgy systems may be represented through the simultaneous statement of Maxwell's equations and the turbulent Navier-Stokes equations. In the paper we shall present a computational technique that may be used for the solution of this problem in real three dimensional systems. The practical, metallurgical implications of these findings are also discussed.
Through the statement of Maxwell's equations the turbulent Navier Stokes equations and the differential thermal energy balance equation a mathematical representation is given of plasma melt heat transfer in arc furnaces in the presence of a foaming slag. The principal role played by the foaming slag is that it acts as an insulator and a reflector of the radiation from both the bath and the plasma jet. These effects are quantified in the paper and compared with experimental, plant scale measurements.
TMS Annual Meeting 55
(11: 10 a.m.)
(1~':8J ,.~.)
3-D FINIJE ELEMENT, TRANSIENT HEAT TRANSFER MODEL FOR ARC WELDING: J. Mazumder, M. Stitt and P. Tekriwal, Dept. of Mechanical Engineering, University of Ilnnois, Urbana, Il 61801 This investigation has led to the development of a three dimensional, finite element, transient heat transfer model for arc welding processes. The purpose of this study was to develop a model which will accurately simulate the heat transfer mechanisms associated with welding and test its basic results by comparisions with experimental data. Future dpvelopments will also include the capability of a complete thermo-mechanical analysis of the weldment. The model's basic equations have been derived from first principles. The finite element form of these equations was developed and the solution process of the ABAQUS program was utilized. Modifications of the ABAQUS program to simulate boundary conditions and generate meshes were also performed. The model was then run for several cases and its accuracy for basic predictions was experimentally assessed. *This work is made possible by a grant from U.S. Army CERL.
PLASMAS FOR METALLURGICAL APPLICATIONS III: Plasma Applications in Extractive Metallurgy Sponsored by the TMS Physical Chemistry Committee Tuesday, March 4, 1986 La Galerie 1 8:00 a.m. Marriott Hotel Session Chairmen: W. C. Roman, United Technologies Research Center, E. Hartford, CT 06108; S. L. Camacho, Plasma Energy Corp., Umsted Industrial Park, Route 8, Box 114Z, Raleigh, NC 27612
(8:30 a.m.) PLASMA REDUCTION OF COBALT SULFIDE:
c. Wai, R. Kearney,
G. Patsakos, K. Prisbrey, Plasma Research Group, U. Of Idaho, Moscow, ID
83843.
~~,-~K
(10: 15 a.m.) LONG-COLUMN PLASMA TORCH FOR THE RECOVERY OF PGM AND OTHER PRECIOUS METALS FROM SCRAP: S. L. Camacho, Plasma Energy
Corp., Umsted Industrial Park, Rt. 8, Box 11-42, Raleigh, NC 27612 A process is described for the recovery of PGM, silver, gold, and other precious metals from recycled materials including spent auto catalysts, electronic scrap, X-ray and photolithographic film ashes, copper sludges, etc. The process used a long-column plasma arc torch to generate the high-temperature environment of about 1,800 0 C needed to produce a very fluid slag from a blend of precious-metal-bearing scraps, reductants, fluxes, and getter metal when required. The high temperature was essential to effect the clean, economical separation between the glassy slag and precious metall~cs, two of the three major byproducts of the plasma heating process. Plasma arc heating provided a virtually massless heat to the recovery process. Plasma delivered the heat and provided other exploitable processing advantages, such as (1) rapid melt rate, (2) control of the melting atmosphere to maximize metallic yields, (3) low exhaust gas flowrate to handle and treat, etc.
(10:45 a.m.) BATH SMELTING OF PARTICULATE MATERIALS IN A PLASMA FURNACE: D.G.C. Robertson. A.E. Morris. University of Missouri-Rolla. Rolla. MO 65401-0249.
A DC transferred-arc furnace with a power supply of 120 kW has been built at UMR as a general facility to study the bath sael ting/ael ting of a wide variety of particulate aaterials. e. g. alneral concentrates and wastes. The powder charge .ay be fed continually through the consullable graphite electrode. The furnace is also being used to conduct basic studies on the incorporation of solid charge into a mol ten bath using submerged gas-powder injection. Both the construction and operation of this laboratory furnace will be described. Measureaents have been aade on heat loss rates and arc voltage and current under various conditions. Bath teaperature distribution and agitation have also been rouehly aeasured. Reaul ta wi 11 be gIven on the ..elting/aelting of soae lIaterials.
A variety of metal oxides are investigated for the reduction of
cobalt sulfide to cobalt metal in a thermal plasma environment. Experimental relative efficiencies and rates of reactions are
compared to thermodynamic calculations based on equilibrium free energy minimization calculations. Efficiency of large scale smelting of cobaltite is discussed.
(9:00 a.m.) RECOVERY OF SILVER FROM SULFIDE MINERALS USING PLASMA SMELTING:
R. Kearney, K. A. Prisbrey, G. Patsakos, C. Wai, Plasma Research Group, U. ·of Idaho, Moscow, ID 938-43 Sil ver recovery from antimonial sulfides such as tetrahedri te poses special smelting problems because of the antimony and arsenic. Gas pollution control is so expensi ve that heavy smel ter penal ti es are incurred. Some producers shi p long distances to find a smelter that will even accept high arsenic concentrates. Plasma smelting offers a low capital cost al ternati ve, yet has high throughputs because of the high temperatures and rapid kinetiCS. In addition, lime can act as a sulfur and arsenic control without severe operating cost penal ti es due to heat i ng the addi ti anal 1 ime. The probl em addressed in this paper is how to take advantage of high temperature plasma smelting for silver recovery. Three different concentrates from the "Sil ver Valley" in northern Idaho are tested. We present recoveries, energy efficiencies, and proj ected economi CS. Resul ts are gi ven for the uni que chemistry possible wi th high temperatures.
(9:30 a.m.) THERMODYNAMICS AND KINETICS OF METAL-OXIDE REDUCTION IN A PLASMA ENVIRONMENT: K. Upadhya, Univ. Of IllinOis at Chicago, P.O. Box 4348, Chicago, IL 60680, J. J. Moore. and K. J. Reid, Mineral
(11 :15 a.m.) RECENT DEVELOPMENTS IN EXTRACTIVE METALLURGY PLASMA PROCESSES: W. H. Gauvin, M. G. Drouet, and R. J. Munz, Chemical Engineering Dept., McGi 11 Un ivers ity, Montrea 1, Quebec, and Hydro-Quebec Research Institue, Varennes, Quebec, JOL 2PO Plasma processes are currently being developed for gas heating, melting, consolidation, thermal decomposition, smelting, refining, extraction of halides, treatment of refractory metals, and production of ceramics. The McGill Plasma Group has collaborated closely with the Hydro-Quebec Research Institute in the design of efficient plasma generators to carry out the above operations ~ These designs will be described in detail, and compared to other industrial designs~ The results of the two plasma groups on melting, ferroalloy smelting, and strategic metal production will be discussed in terms of reactor flexibility, continuous operation, high energy efficiency, high conversion, and purity level of product. A review of large industrial plasma furnaces will be presented, and contrasted with the use of conventional arc furnaces up to 40 MW~
POWDER METALLURGY TMS-AIME General Abstract Session Tuesday, March 4,1986 Mardi Gras H Marriott Hotel 8:30a.m. Session Chairman: Patrick McGeehan, Hoeganaes Corporation, Taylors Lane, Riverton, NJ 08077
Resources Research Center, 56 East River Road, Minneapolis, MN
55455 The potential for the application of plasma technology in metal oxide reduction and in iron and steelmaking is discussed. Established thermodynamic and kinetic principles are used in postulating the mechanism{ s) of metal oxide reduction in a plasma environment. On the ~asis of this thermodynamic and kinetic analysis, the likelihood for the formation of the various metallic phases is examined. Also, the advantages and limitations of plasma reduction/smelting as applicable in ferrous extraction metallurgy is discussed, and its potential to seriously challenge the Blast Furnace/Basic Oxygen Steelmaking route is considered.
(8:30 a.m.) MICROSTRUCTURE AND PROPERTIES OF PLASMA-SPRAYED STAIN· LESS STEEL/CARBIDE MATERIALS: Ann M. Ritter and M. R. Jackson General Electric Corporate Research and Development, P. o. Box 8 Schenectady, NY 12309, and R. N. Wright, Rensselaer Polytechnic Institute, Troy, NY 12181. Low pressure plasma deposition has been used to produce bulk samples
0
316 stainless steel containing 5-30 voiume-percent titanium carbide The morphology of the melted and deposited TiC and steel powder wa
56 TMS Annual Meeting lamellar or splatted, with un melted particles of both powder type present in the structure. The grain size of the stainless steel matri: decreased with increasing amounts of TiC, and intergranular preciplta tion of secondary carb ides (M 2 C 6 and M C ) was observed. Roor temperature mechanical properties most ltr6ngly influenced by th! addition of TiC were yield strength (0) and strain to fracture ('fl' witl a increasing and E f decreasing witt?' increasing amounts of TiC. B c3'mparison, room temperature fracture stress (Of) was insensitive t 0 carbide additions. At 760 C, the presence of 5-[6 v /0 TiC had littI effect on Of and E , but resulted in some increase in a relative to 31 f stainless steel. Larger amounts of carbide (30 v /0) 2'aused a marke increase in a y and O"t and a decrease in f f"
refinement and by homogeneous incorporatlon ot' larger concentrations of dispersoid- and precipi tate-forming elements than can be achieved by can ven t ional i ngot-metall urg ical process ing. To assess the relative contributions of these mechanisms to improved strength i:l RSP Mg- Al alloys, ext rus ions of Mg-18Al, Mg-1 2. SAl, Mg-15Al, Mg-12.5AI-0.2Zr, and Mg-12.5Al-1.5Si alloys made from
roller-quenched flakes have been prepared and tested. The effects on strength of varying Mg Al precipitate concentrations; 17 12 SUbstructural refinement by Al zt- dlspersoids; and dispersion strengthening by incoherent Mg~Si particles have been determined. The effect of RSP on corrosion reSistance of Mg-Al alloys has been determined by weight-gain measurements during constant immersion in 3.5% NaCl solution.
*
Research conducted under the HcOonnell Douglas Independent Research and Development program.
(8:50 a.m.) MICROSTRUCTURE AND PROPERTIES OF LIQUID-DYNAMIC COMPACTED Al-4Li-
lCu-O.2Zr:*
P. J. Meschter, R. J. Lederich, and J. E. O'Neal,
McDonnell Douglas Research Laboratories, St. Louis, MO, 63166, and E. J. Lavernia, Dept. of Materials Sci. and Eng., M. I. T., Cambridge, MA 02139.
In liquid-dynamic compaction (LOC), a stream of ultrasonically atomized alloy droplets is deposited onto a cooled substrate, forming a 98-99% dense deposi t. This deposit can be processed directly into a product form, thus bypassing numerous steps involved in conventional powder consolidation. LOC has been applied here to a low-density (2.42 g/cm 3 ) Al-4Li alloy.
Sheet
material processed from an LOC compact has fewer oxides and inclusions than does comparable material obtained from a powdersource extrusion. The ductility and notch tensile stress/yield stress ratio of the LOC-source sheet are substantially larger than those of the conventionally processed alloy. Improved properties of LOC-source material are discussed in relation to microstructural development during LDC and conventional
(10: 10 a.m.) MICROSTRUCTURE AND MECHANICAL PROPERTIES OF HIGH ENERGY RATE P/M PROCESSED ALUMINUM ALLOY X7091: G. Elkabir, C. Persad and H. L. Marcus, Center for MS&E and T. Aanstoos, CEM, The University of Texas, Austin, TX 78712 The ALCOA Al-Zn-Mg-Cu-Co P/M Alloy X7091 has been investigated using a novel high energy rate consol idation method. Degassed powders were subjected to a pulsed high-current discharge under low pressure. The pressure was increased during the discharge. Consolidation products have been evaluated to determine structure/mechanical property/processing relationships and to model the densification process. The results indicate that with adequate degassing, microstructures comparable to vacuum hotpressed material are developed and that improvements by further processing are possible. This research was 2269-85-C-0222.
supported
by DARPA,
under NADC Contract N6
program.
(10:30 a.m.)
9: 10 a.m.) ICAL PROPERTIES OF A LIQUID DYNAMIC CONSOLIDATED (LDC) LLITE ALLOYS 21: Ghanshyam Rai, Cabot Corporation, 1020 w. k Ave., Kokomo, IN 46902-9013 Liquid dyu.a1c consolidation (LDC) is a recent developtEtent in tEtetal p.rticula~e tech.nology. It nas tEtany advantages of the P/M processing but without salle of the deterioration in properties brought about by tEtulti-stage handling of powder process. Stellite alloy 21, a Co base alloy, used for hard faCing applications, with good oxidation and thermal shock resistance, was processed by LDC. LOC deposits of weights ranging from 20 to 30 lbs. in a variety of cross sections and lengths were produced. LVC deposit density ranged fcom 95 to 99 percent of the cast density depending on such parameters as atomizing gas pressure, substrate materials etc; It was found that the atomizing ga8 pressure and metal to gas ratio were perhaps the most important factors in determining the relative density of the deposits. All the deposits produced ex.hibited a microstructure comprising well defined grain structure (25-301& grain size) with no evidence of any cast structure and precipitates. The microstructure of the deposits was very much similar to the wrought product except for the presence of porosities. Electric discharge machining (EDH) was performed to machine out bars for tensile testing and extrusion. Extrusion of EDH bars was carried out at a temperature of 1200DC with an extrusion ratio' of 7:1 approximately. There was no evidence of any porosity in the extruded structure and as a result of extrusion, the grain .ize was reduced to approximately 101AD or less in size. Tensile testing at roolll and elevated temperature showed that the material haa both improved ductility and superior strength properties.
INVESTIGATION Of POWDER !1ETALLURGY INJECTION !10LDING: B. R. Patterson. R. J. Waiker, R. S. Libb~ University of Alabama at Birmingham(UAB), Birmingham, Alabama
Research was carried out to study the various aspects of p/M injection molding. This process involves the mixing of powder metals with suitable binders, injection molding the mixture, debinding, and then sintering. The goal of this research was to examine the basic principles involved in injection molding rather than prodUCing a particular part with a specific geometry. The potential uses of different binder systems, methods of binder preparation, order of mixing, and rheological properties were investigated. Another considerably important aspect of the study was debinrling teChniques. Different binders require
different debinding procedures and times which depend upon the individual characteristics of each hinder. The effects of metal powder particle size, size distribution, shape, and some bulk properties play an important role in this process. Mold design is a crucial factor in determining the quality of the end product. Although stainless steel was the prinC:ipal powder of study a variety of others were investigated.
(10:50 a.m.) THE EFFECT OF THERMAL TREATMENT AND IMPURITY CONTENT ON BLENDED ELEMENTAL plM Ti-10V-2Fe-3Al.*; J. E. Costa, N. R. Moody, and J. E. Srnugeresky, Sandia National Labora tories, Livermore,
(9:30 a.m.) MICROSTRUCTURAL DECOMPOSITION OF RAPIDLY SOLIDIFIED ALLOYS DURING CONSOLIDATION: D. J. Miller, J. W. Zindel and H. L. Fraser, \»pt. of Metallurgy ~ "11ning Engineering, University of Illinois, 1304 W. Green Street, Urbana, IL 61801. The microstructural decomposition of several rapidly sol idified alloys as a result of consol idation processing has been characterized using light optical and transmission electron microscopy. Particulate from melt spun ribbon was consolidated by dynamic compaction and extrusion. Dynamic compaction produced only sl ight microstructural changes. Extrusion resulted in 1 argely decomposed microstructures even at temperatures at which the alloy was thermally stable. To examine this effect further the result of both cold work and hot work on the mi crostructure of Al-8Fe-2t-b Was invest i gated.
CA 94550.
Blended elemental plm Ti-10V-2Fe-3Al can be strongly affected by both internal defects and thermal treatments. In this work defect size and distribution have been varied by thermomechanical processing and by the utilization of different purity materials. Improvements in tensile properties from those of the as-sintered material were achieved by vacuum annealing above the beta transus even though the density and pore distribution remained constant. HIPping at the same temperature as vacuum annealing resulted in lower YS and UTS but in increased ductility over the vacuum annealed rna terial. Differences in material purity, particularly Cl content, has been hypothesized to affect defect size and distribution, which in turn affects mechanical properties. The present work suggests that post-sinterring heat treatment can reduce the need for HIPping. This work supported by V,S. Department of Energy under Contract
*
Number DE-AC04-76DP00789.
(9:50 a.m.) RAPID SOLIDIfICATION PROCESSED (RSP) MAGNESIUM-ALUMINUM ALLOYS:'
(11:10 a.m.)
P. J. Meschter, R. J. Lederich, and J. E. O'Neal, McDonnell Douglas Research Laboratories, St. Louis, MO 63166.
RELATIONSHIP BETWEEN PARTICLE SIZE DISTRIBUTION, MICROSTRUCTURE AND SINTERING OF TUNGSTEN: B. R. Patterson, V. D. Parkhe, C. V.
Previous research on rapidly solidified Al- and Mg-base alloys has shown that RSP improves mechani cal properties by grain
Serial sectioning was performed to obtain the. microstructural parameters such as volume porosity, surface area of pore, average
French, University of Alabama at Birmingham (UAB) ,B'ham, Ala.
TMS Annual Meeting 57 number of faces per grain, and distributions of pore lengths, diameters and volumes. A computer model was developed to predict these same microstructural parameters as a function of particle size distribution and to compare the results with those obtained through serial sectioning. Narrow and wide powder size distributions were used to compare the model with the serial sectioning, The model predicted that wider powder size distribution results in smaller average pore sizes with larger variation in pore size. The predicted average number of faces per drain are in close agreement with the experimentally obtained values, thus demonstrating the utility of the computer model.
(11 :30 a.m.) A SIHPLIFIED MODEL FOR STABLE OPEN POROSITY': F. A. Nichols, Materials Science and Technology Division, Argonne National Laboratory, Argonne, IL 60439.
A simplified model is developed for a stable network of interconnected porosity in a polycrystalline material. Rectangular parallelipipeds are assumed to represent grains, with cylindrical tubes of porosity along all edges. Adapting the theory of shape instabilities for infinite cylinders to finite segments, the model predicts a critical volume fraction (or swelling) for a stable/unstable condition of '\.5-6% for equiaxed grains. This is in good agreement with many experimental results for the onset of isolated porosity during sintering and the onset of interconnected porosity during the swelling of ceramic nuclear fuels. The model also predicts much larger critical values for significantly elongated grains and in particular indicates that the open-tunnel mechanism of fission-gas release in ceramic nuclear fuels does not apply to elongated or columnar grains. *Work supported by the U.S. Department of Energy
(11:50 a.m.) PLASHA PRODUCED SUBMICRON METAL POWDERS:
SYNTHESIS AND PROPERTIES:
p~
Lo Martin, G. J. Vogt and H. Sheinberg; Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos,
NM
87545.
An R. F.
generated inert gas plasma has been used to decompose organometallic compounds and to refine metal powders. The resultant spherical powders have varied in size from 20nm to 20~lm with the majority being in the 0.05 to 0.311m range. In addition, ultrafine ceramic particles, ::'O.lwm in diameter, have been produced simultaneously such that sintering the powders yields a dispersion strengthened alloy. Initial studies have concentrated on the Ni+A1203 system although preliminary trials using Ti-Al intermetallic compounds will be presented. The powders and compacts have been characterized by TEM,SEM,BET, optical metallography and tensile deformationL' These results will be discussed in light of the plasma synthesis parameters and the microstructures produced by consolidation, cold rolling and high temperature recrystallization. This work has been sponsored by the U.S. Department of Energy.
PRETRANSFORMATION BEHAVIOR RELATED TO DlSPLACIVE TRANSFORMATIONS IN ALLOYS III Sponsored by the ASM-MSD Structures Committee Mardi Gras I-J Tuesday, March 4,1986 Marriott Hotel 8:30 a.m. Session Chairmen: R. Sinclair, Stanford University, Stanford, CA 94305; L. E. Tanner, Lawrence Livermore National Lab., Livermore, CA 94550
(8:30 a.m.)
(8:55 a.m.) X-RAY DIVEKGENT B[,\1'l INVESTlCATION OF PREMARTE~SlTlC STRAl~ E~TECTS IN B NL\l ALLOYS:;" X.C. He, L.H. Lee, \~.E. :-layo and
Dept. of Hechanics and Haterials Science, C:ollegt.; , Rutgers University, Piscataway, N.) 08854. Back-reflection divergent beam patterns were obtained from 8-NiAl crystal plates ranging from 46 to 637. Ni content. The crystals exhibitLOd a remarkahle degree of perfection, yielding generally closed elliptic']l patterns without ruptures caused by substructural defects. For the Ni-poor alloys the diffuse scattering was so pronounced that the Ka doublets overlapped. Tn the Ni-rich allovs the diffuse scattering was greatly reduced and the Ko: uoublets were well separated LOxcept for the (220) line patterns. These displayed local broadening effects of the Kcx doublets and significantly exhibited local displacements of the elliptical patterns. The preliminary results are interpreted in terms of atumic displacement strains on (110) planes and local defect structure. A complete strain tensor determination involving data acquisition from many different directions awaits the procurement of cubic-shaped crystals. )';Th~s work is supported by the Div. of Materials Research of NSF under Grant DMR-8l04985.
(9: 20 a.m.) NElITRON SCATTERING FROM PRE-MARTENSITIC In-T! ALLOYS;*
T.R. Finlayson, Department of Physics, Monash University, Clayton, Victor!."!, Australia, 316R and H.G. Smith, Solid State Division, Oak Ridge National Lahoratory, P.O. Box X, Oak Ridge, Tennessee, 17R10. A set of measured phonon dispersion curves for In-Tl at a temperature slightly greater than the structural transformation temperature_T has failed to show phonon m softening for the [l:I;:Oj [I;:l:0l branch to within I;: :: 0.15 of the zone centre. To reconcile this with the known softening of the elastic constant, 1/2 (C 11 - C ) requires 12 that the dispersion curve show a strong positive curvature at low I;: along this branch. A current experiment is being planned to study more closely the rl;:l:Oj [I;:~Oj branch at low I;: and its temperature dependence in the vicinity of Tm and the results will be presented. The impli~ations for our understanding of the precursive lattice vibrational oroperties of In-Tl will he discussed. *Research sponsored by the Division of Materials Sciences, U.S. Deoartment of Energy under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.
(9:45 a.m.) ELECTRON DIFFUSE SCATTERING STUDIES OF PRE-MARTENSITIC
ALLOYS: B' Cu-Zn, B' Ni -AI, In-TI and Fe-Ni; T.R. Finlayson, Department of Physics, Monash University, Clayton, Victoria, Australia, 316B, A.J. ""torton, CSIRO, Division of Chemical Physics, Clayton, Victoria, 3168 and P.O. Norman, Chisholm Institue of Technology, Caufield, Victoria, 3162.
Electron diffuse scattering patterns obtained from BI Cu-Zn, B' Ni-AI, In-Tl and Fe-Ni alloys in their pre-martensitic conditions have been analyzed and compared with Kohn constructions which map Fermi surface segments into the scattering plane. Because of the close correlations between these patterns and constructions, it appears likely that the diffuse electron scattering may be viewed as arising from conduction-electron energy effects on the structure of these alloys. A comparison of the diffuse scattering observations will be made and the possible role of Kohn anomalies as a precursive phenomenon discussed.
(10: 10a.m.) HREI~
QUASI-ONE-DIMENSIONAL MODEL OF PRETRANSITIONAL SOFT MODE BEHAVIOR S. Mendelson, The City Univ. of New York, New York, NY 10031.
OBSERVATIONS OF "TWEED" IN NI-AL AND CU-ZN-AL G. Van Tendeloo and S. Amelinckx, Univ. of Antwerp (RUCA), Belgium; R. Gronsky, NCEM, MMRD, Lawrence Berkeley Lab., Serkeley, CA 94720; and L. E. Tanner, Physical Metallurgy Sect i on, Lawrence Livermore Nat. Lab., Livermore, CA 94550.
In this talk we describe the QOO soft mode model for martensitic transformations and its relation to pretransitional behavior. In this model* the structural change has its origin in one dimensional fluctuating ionic shifts along <001> (or in some cases along <011> or < 111» wh i ch give rise to two coupled correlations (one-dimensional microscopic and three dimensional macroscopic). The fluctuating ionic shifts along <001> increase their correlation and decrease their frequency as T+ Tm and 1ead to soften i ng of the <001> longitudinal acoustic PllOnons and the Cll elastic constant. The resulting internal tensile stress manifests itself as a resolved shear stress on a {Oll} system and leads to softening of transverse acoustic phonons with wave vector CiII[OllJ and polarization (;11[0l1J, and the C'=(Cll-C12)/2 e 1 as tic cons t ont. Mendelson, Ferroelectrics, 22 (1984), 265.
High resolution electron microscopy provides a simple method to determine the origin of diffuse scattering in electron diffraction (EO) patterns. Ni-Al and Cu-Zn-Al are two examples which are known to exhibit intense diffuse scattering along [llOJ directions. Under high resolution observations Ni-Al shows a pronounced tweed contrast even on an atomic scale whi Ie Cu-Zn-Al exhibits a mottled image without a preferential tweed direction. Optical diffraction (00) of both images confirm this difference. The 00 of Ni-Al is almost identical to its EO with the same pronounced [110J streaks while the 00 of Cu-Zn-Al only produces sharp basic reflections without diffuse streaks. This indicates that the dominant part of the diffuse scattering of Ni-Al is effectively static in nature while for Cu-Zn-Al it is dynamic. Simi 1 ar HREM observat ions have been made for Cu-8e and Cu-Au.
*s.
58 TMS Annual Meeting
(10:35 A.M.) BREAK
(10:45 a .1'1.) TWEED STRUCTURES ASSOCIATED WITH FCC-FCT TRANSFORMATIONS IN Fe-Pd ALLOYS;
R. Oshima, M. Sugiyama';~ and F. E. Fujita, Department of Material Physics, Faculty of Engineering Science, Osaka University, Toyonaka, Osaka 560, Japan The remarkable tweed contrasts were observed by electron microscopy in two types of cubic to tetragonal transitions of Fe-Pd alloys, (a) thermoelastic fcc-fet martensite transformation of the
alloys
with
about
30at%Pd,
and
(b)
fcc-Llo
order-disorder
transition of near equiatomic FePd alloys. It was found that the tvieed contrast in the former, which appeared in the temperature range up to lOOK above the Ks is a strain contrast induced by the static displacement of atoms, 6{ llO} /<110>, associated with the formation of very thin platelets of martensite nuclei. The other tweed contrast found in the early stage of ordering pr.ocess in the alloys is also a strain contrast due to the formation of range order domains. Nippon Steel Corporation,
ELECTRON MICROSCOPY STUDY ON THE CUBIC-TETRAGONAL To Onozuka & N. Ohnish1; The Research Institute & Other t'-ietals, Tohoku Un1versity, Senda1 980,
phase transformation above Tc of the superting compounds Nb Sn and V3S1 has been 1nves~lgated by . 3 1SSlon electron m1croscopy at 1000 kV. Part1cular attentIon was drawn to the microstructure of so-called tweed patterns associated with the pretransformat1on above Tuo Reversible changes of were observed in the the patterns on heating and cooling temperature range 10-60 K and analyzed uSIng a v'rR system. These results suggest the presence of localIzed lattice distortion having non-cubic symmetry at temperatures above the TMo
(11 :35 a.m.) PHASE TRANSrORHATIONS AND HODULATED STRUCTURES IN Ti-AJ-Nb ALLOYS:
R. Strychor*. J. C . .williams* and W. A. 50ffa**. *Carnegie-~1ellon University. Pittsburgh. PA 15213, **University of Pittsburgh, Pittsburgh. PA 15261 The bcc S-phase in Ti-Al-Nb alloys exhibits a wide variety of transformations upon cooling. The transformation products depend on composition and quenching rate. ~1any similarities are found between the transformation observed to occur in the above-mentioned alloys and those exhibited during COOling of many noble metal and shape-memory type S-phase alloys. Among these are the formation of a CsCl (82) superlattice over a wide compositional range and the subsequent appearance of "tweed-l ike" or modulated structures with associated diffraction effects. These phenomena have recently been interpreted by many investigators as being "pre-martensitic" in origin. Examination of the specific alloys under question show that many of these anomalies can be attributed to the incipient formation during quenching or aging of an {V-type phase in the parent CsCl structure. This r.ll-phase occurs over a wide range of quench rates and aging temperatures and appears to possess greater stabil i ty than similar type phases observed in other a lloy systems.
(12: 00 noon) TWEED IUCROSTRUCTURE IN Y203 STABILIZED Zr02 A. H. Heuer, V. Lanteri, and R. Chaim, Case Western Reserve University, Cleveland, OH 44106. "Tweed" microstrucyure develop in Y203-Zr02 alloys containing 8-12 w/oY203 given certain heat treatments. In this system, the tweed structure is almost certainly due to a fine dispersion of precipitates. The growth of these precipitates has been studied, as well as their effect on a martensitic cubic-tetragonal transfonnation that occurs on quenchi ng in thi s system.
PROCESS MINERALOGY APPLICATIONS TO MINERAL PROCESSING Sponsored by the TMS-SME Process Mineralogy Committee La Galerie3 Tuesday, March 4,1986 Marriott Hotel 8:30a.m. Session Chairmen: Tsu-Ming Han, Ore Research Laboratory, 504 Spruce Street, Cleveland-Cliffs Iron Company, Ishpeming, Michigan 49849; James N. Hartley, Battelle, Pacific Northwest Laboratories, Battelle Boulevard, Richland, Washington 99352
(8,]0 a.m.)
EVOLUTION OF PELLETS PROCESSED fROM MAGNETIC ORE CONCENTRATES:
T.M. Han, The Cleveland-Cliffs Iron Company, Ishpeming, Michigan
49849
Pellets processed from the magnetic ore concentrates possess two distinctive features that are not observed in pellets processed from other types of iron ore concentrates. 1) As many as three concentrically arranged textural-mineralogical zones, i. e. mosaic hematite, porphyroblastic hematite, and granular magnetite. 2) Practically no internal cracks cross-cutting into the mosaic hematite shell. These features result from the textural and mineralogical evolution of magnetite in pellets during the preheating, indurating, and cooling stages, not only in pellets fired by the grate-kiln-cooler system but also in those fired by the traveling grate and shaft furnace. This paper describes the compositional and textural changes that take place at each of these stages in the grate-kiln-cooler system. The study suggests that the zonal structures and the internal cracks are developed through quick drying, progressive oxidation, recrystallation, and retrograde oxidation. The retrograde oxidation plays a key role in determining the physical and reduction properties of the final pellet product.
(9:00 a.m.)
PRELIM [NARY I NVESTI GATION OF GRAPH iTE RESOURCES IN MI CH I GAN: HwanJ!., D,H, Carlson, A,M, Johnson, Michigan Technological University, Institute of r'iineral Research, Houghton, Mf 49931; J. Van Alstine, Geological Survey Division, Michigan DNR, Region I, Marquette, MI 49855. A preliminary geological, mineralogical, and beneficiation investigation of Michigan graphite resources has been undertaken. The graphitic rock belongs to the middle Precambrian Michigamme Fonnation, which has carbon contents ranging from 15 to 30%. An initial conservative estimate indicates that the resource amounts to more than 3 bill ion tons. Heavy 1iquid and flotation separat ions on the mi nus 400 mesh feed ma teri a1 were found to yi e1d i ncompl ete separations, e.g. 50:, carbon recovery at 60% C grade by heavy liquids. A subsequent mineralogical study revealed that poor liberation was the major reason. Very fine laminations of clays, quartz, and other minor minerals are interfingered with aggregates of graphite. These aggregates are mostly below 30 micrometers with individual graphite flakes smaller than 5 mi crometers. ~,Y.
(9:30 a.m.)
RECOVERY OF Nb/Y/REE/Th FROM A NORWEGIAN ORE BY HIGH GRADIENT fl!\GrIETIC SEPARATION: J.Y. flwanq, r·1ichigan Technological University, Institute'of MineralReSearch, Houghton,MI 49931; G. Kullerud, Dept. Geosciences, Purdue University, W. Lafayette, IN 47907. Niobium, yittrium, rare earth elements, and thorium are found enriched in an ore from Seterasen, Norway. Mineralogical study shows that the major phases of this ore are feldspar (about 7080%) and ferromagnesian silicates (about 15-20%), including pyroxene, hornblende, and biotite. Minor and accessory minerals are apatite, zircon, allanite, pyrochlore, magnetite, ilmenorutile, goethite, and chlorite. Pyrochlore and allanite are the phases which contain roost of the Nb/Y/REE/Th elements. The two minerals occur as minute grains, often smaller than 20 microns. High gradient magnetic separation at minus 20 micron feeds was conducted to concentrate these elements. The results show that up to 84% of these valuable elements can be recovered at a magnetic field strength of 1.4 tesla and a slurry flow velocity of 10/ cm sec. Mo re than 70% of the feed are rej ected in the nonmagnetic fraction, which primarily contains feldspar.
(10:00 a.m.)
PLATINUM GROUP MINERALS IN THE DULUTH COMPLEX AND THEIR BENEFICIATION BEHA V IORS: T. Sabe l i n, I. Iwasaki, and K.J. Reid,
Mineral Resources Research Center, University of Minnesota, Minneapolis, MN
55455
Platinum group element (PGE) minerals were found in a drill core from the mineralized zone in the basal portion of the Duluth
TMS Annual Meeting 59 Complex. They occur in disseminated sulfide ore and show an affiliation with Cr-rich horizons. Previous studies of massive sulfide ore indicated a close association of PGE minerals with nickel arsenide and special problems associated with their recovery by flotation have been reported. In the disseminated ore PGE occur as alloys, sulfides and sulfarsenides both as discrete grains and associated with base metal sulfides. Magnetic separation preconcentrates the PGE in the nonmagnetic tails. Further recovery will probably require special beneficiation techniques, particularly for such phases as Pt-Fe alloy.
REDUCTION TECHNOLOGY III: Energy ConsumptionProcess Control and Anode Effects Sponsored by the TMS Light Metals Committee Tuesday, March 4, 1986 Pontchartrain Ballroom D 8:30 a.m. Sheraton Hotel Session Chairman: Mr. Pierre Baillot, Director of Technology Sales, Aluminum Pechiney, 38340 Voreppe, France
(10dO a.m.)
BENEFICIATION OF OXIDIZED TACONITE BY HIGH INTENSITY MAGNETIC SEPARATION-FLOTATION: Howard D. Jacobs, Twin Cities Research Center, Bureau of Mines, Minneapolis, MN A Mesabi Range oxidized taconite was beneficiated to commercial grade using a flowscheme that included wet high intensity magnetic separation and cationic flotation (WHIMS-CF). Continuous testing was preceded by batch WHIMS-CF tests to provide essen:tial operating parameters such as feed slurry velocity, feed size and solids, and magnetic field strength. In continuous testing using a feed having a median particle size of 15 \-lm and a medium size expanded metal matrix energized to a magnetic field of 7.4 kilogauss (kG) the separator concentrate of 56.3 pct iron was further upgraded by flotation to 63.8 pct iron and 80 pct iron recovery (FeR). Using a feed median particle size of 30 lJm and a matrix of 6.5 mm steel spheres energized to a magnetic field of 4.8 kG produced a separator concentrate of 57.4 pct Fe further upgraded by flotation to 63.6 pct Fe with 93.6 pct FeR. Estimated total processing costs us~ng the WHIMS-CF flowscheme will be lower than selective flocculation-des liming-cationic flotation and reduction roasting-magnetic separation-cationic flotation.
(8:30 a.m.) HISTORY OF ELECTRICAL ENERGY CONSUMPTION BY HALL HEROULT CELLS: Warren Haupin, 2820 7th Street Rd., Lower Burrell, PA 15068
The first commercial aluminum cells at Neuhausen~ Switzerland (Heroult) and Pittsburgh, PA. (Hall) required more than 40 KWH/kg (l8KWH/lb) of almninum produced, and had current efficiencies ranging from 75 to 78%. Today the best cells require less than 13 KWH/kg (5. 9KWH/lb) of aluminum produced and have current efficienCies ranging between 94 and 96%. Early improvements were achieved, first by using larger 1 more closely spaced anodes, then by increasing the cell's size. As the cell's size was increased, electromagnetic problems arose. The current carrying molten
~~~l~U~ik!t~~d~l;~i~~~c~~~o~~ th Iihte~~~~e~~~e~~~~~ ~~ ~~~~~~{:iiJ and calculate these forces. Further development was based upon phYSical and mathematical models - work that continues even today. At the same time, studies were made of the chemistry of the electrolyte, electrode reactions, and how these and other factors influenced the current efficiency. The latest improvements came from computer control of the process coupled with automated feeding of alumina to the cells.
(11:00 a.m.)
(9: 15 a.m.)
FLOTATION KINETICS AND ORE MICROSCOPY FOR A GALENA ORE: Scott L. Volner, P.O. Box 1193, Elko, NV 89801, and John L. Watson, Fulton ~University of Missouri-Rolla, Rolla, MO 65401.
ALUMINIUM PECHINEY 280 KA POTS: B. Langon, Aluminium Pechiney LRF, 73300 St-Jean-de-Maurienne, France; P. Varin, Aluminium Pechiney, Aluval, 38340 Voreppe, France - - - -
The flotation kinetics of several galena ores from Viburnum, MO were investigated to permit an analysis of flotation problems in terms of ore mi nera logy, as determi ned by the use of ore mi croscopy. The results indicate that a first order rate model, with two galena and two gangue components, may be used to represent the flotation system. The variations in kinetic parameters were then shown to be 1 inked to the mi nera logy of each ore and a major contributor to flotation problems in the ores investigated was the presence of cerrusite, which is an oxidation product of galena. In addition the entrapment and recovery of gangue particles was demonstrated to be a significant contributor to flotation problems in the Viburnum area.
As a result of four years of extensive tests carried out on four prototypes, the St. Jean-de-Maurienne Research Laboratory has perfected a new model of reduction pot. Developed with the help of advanced computer models, this new generation of industrial pots functions with a nominal amperage of 280 k.A a current efficiency of 95% and a DC power consumption of 12,900 Kwh/T. These results as well as the different measurements taken on the operating prototypes are in complete agreement with the predictions of the models. A first potline of 120 pots is currently in the start-up phase at the St. Jean-de-Maurienne plant.
(9:40 a.m.)
INCREASING AMPERAGE IN AN EXISTING SMELTER BY INCREASING ANODE PIN SIZE; B. Michael Baltzell, Eastalco Aluminum Company, 5601 Manor Woods Road, Frederick, Maryland 21701, U.S.A. (11:30 a.m.)
1 1 = AND DEEP-CLEANING OF CANl\DIAN HIGH-SULPHUR COALS: G. I. Mathieu; Energy, r'lines & Resources Canada, 552 Booth St., ottawa, Canada KIA OGl A revolution is taking place in the physical beneficiation of coal because of envirol1!T'e11tal and energy problE!T1S. Advanced developments in multidiscipline science and engineering technologies are'required to solve the variety of problE!T1S that face the coal ?reparation engineer in producing an envirol1!T'e11tally acceptable and economically oompetitive fuel. The orocessing of fine coal has been a long-standing problem, partly attributed to insufficient knowledge of the mineralogy of coal as well as inadeauate beneficiation rrethods. In this study, two Canadian coals were characterized using soPhisticated mineralogical techniaues, and the findings were used 'for develooing the best coal cleaning procedures. .lith a progressive grinding and or=essing aooroach, using successive flotation and magnetic separation rrethods integrated with the mineralogical studies, it was possible to rerrove 95% of the ash and sulphur-bearing minerals fran both coals. The end products analyzed 0.8 to 1.6% sulohur and ash, and the therrral yield and Xlsts were acceotable.
Additional metal production from an existing prebake smelter was accompl ished by increasing the anode pin diameter. The higher heat flow from the top of the pot resulted in a more balanced pot operation, higher operating amperage, and lower anode resistance.
(10:05 a.m.) STABILITY OF ALUMINIUM REDUCTION CELLS - A NEW APPROACH : R.J. MOREAU and D. ZIEGLER - GIS MADYLAM - ENSHG - BP 95 38402 SAINT MARTIN D 'HERES CEDEX - France
Small periodic disturbances are superposed to the equilibrium shape of the interface between cryolite and aluminum, and a linear analysis of their properties is proposed. Perturbations of electric quantities are first calculated, and then perturbations of velocities and pressure in the two liquids follow from 3D Navier-Stokes equations with a linear drag. The result is a characteristic equation which relates the parameters of the disturbance (wave length, rate of amplification) to the parameters of the cell (current densities, thicknesses of liquid layers, friction coefficients~ equilibrium velocities ... ). It'is found that two different kinds of instabilities may develop. One is the classical Kelvin-Helmoltz instability of sheared interfaces slightly modified by WID effects ; it may generate small scale disturbances (20 em). The other is a new instability, essentially electromagnetic in nature, able to generate large scale waves (1.5 m) propagating in the direction of horizontal current.
60 TMS Annual Meeting (10:30 a.m.) ANODE EFFECT PREDICTION: Harry J. Meyer, Intalco Aluminum Corp., P.O. Box 937, Ferndale, WA 98248, Dave G. Earley, Intalco AllDUinum Corp., P.O. Box 937, Ferndale, WA 98248
(9:45 a.m.) HIGH TEMPERATURE IN-REACTOR TESTING OF ~b-lZr, PWC-ll AND T-lll: S. D. Atkin, P. J. Puigh, and W. L. Hue, Westinghouse Hanford Company, Rlchland, WA 99352
Anode effects are a characteristic phenomenon in aluminum electrolysis. Resistance versus time graphs, on operating side-
Abstract Not Available
break, prebake pots, were studied for the 15 minutes prior to anode effects.
It was found that these pot resistance graphs
have a characteristic rise in pot resistance leading to the anode effects. A computer algorithm was developed based on average pot resistance and slope of the characteristic pot resistance versus time curves. The algorithm has proven to be 91% effective in predicting anode effects and the pot operators have been able to get to and treat 93% of the predicted anode effects. Pot operators respond to lights installed above each pot that blink when an anode effect is predicted. Operators treat the predicted anode effect by breaking and feeding one side of the pot. This algorithm has been applied, for a period of time, to thirty operating pots yielding no operational problems and an average of 75% savings in anode effect overvoltage and 70% savings in anode effects per pot.
(10:10 a.m.) DEVELOPMENT OF A MOLYBDENUM-RHENIUM ALLOY FOR SPACE NUCLEAR REACTORS: L. B. Lundberg, Los Alamos Na ti ona 1 Laboratory, Los Alamos, NM 87545 Abstract Not Available
(10:35 a.m.) OBSERVATIONS ON THE BEND DUCTILITY OF A GTAW Mo-13 Re ALLOY, R. L. Anunon and R. W. Buckman, Jr., Westinghouse Advanced Energy Systems Division, Box 10864, Pittsburgh, PA 15236-0864
EFFECT SUPPRESSION PROGRAM: Julio Bereciartu, Ciudad Guayana, Estado Bolivar 8015, Venezuela it was put into operation, the anode effect suppression performance was measured to be 88.92 and lately 100% t. This efficiency depended upon hard, and later, super ffects. The method of evaluating it consisted of comanode effects programmed for automatic squelching versus effects put out in automatic. The time needed to extinan anode effect dropped from 4 to 2.7 minutes processwise. or power consumption savings was obtained by decreasing the tion of the anode effect from 3 to 1 minute voltagewise; this brought about a power reduction from 0.242 KW to 0.026 KW per light. Green pole consumption was reduced from 600 to 373 poles per day. Cost for operation due to manual suppression of anode effects was reduced also.
___________ OF AUTOMATIC ANODE EFFECT KILLING EITHER BY POWER OR BY AIR BLOWING: Knut A. Paulsen, Hydro, Karm~y lants, N-4265, Havik, Norway; Th. Mellerud, Hydro Research Cpntre,Porsgrunn, Norway; J. G. Thuestad, Hydro, Karm~y Plants, 265, Havik, Norway
~
NTERRUPTION
On S~derberg pots, anode effect killing by means of anode pumping has disadvantages compared to its use on prebaked pots. Other methods such as air blowing through holes in the anode or power interruption to the pot might be more convenient. The method of interrupting the current through the pot is the focus of this paper. Anode effect killing efficiency, pot voltage and pot current behavior during interruption are described and discussed.
REFRACTORY METALS AND ALLOYS IN NUCLEAR APPLICA TIONS I: Space Power
A binary alloy of molybdenum containing 13 weight percent rhenium is being considered for application in space nuclear power reactors. Rhenium addi tions to molybdenum have been shown to improve the low temperature ductility of molybdenum. However, to be considered as a useful structural material, low temperature ductility in the as-welded condition is considered essential. To evaluate the as-welded ductility of Mo-13Re, annealed sheet material, automatic, autogenous bead sheet welds were made using the GTAW process under controlled environmental conditions. Ductilebrittle behavior was determined following the procedure of the Materials Advisory Board for ductile refractory metal alloys. In the annealed condition, the ductile to brittle transition temperature was -50°F. In the as-welded condition, the ductile to brittle transition temperature was +400°F, an increase in the DBTT of approximately 450°F. Material for test was prepared by nonconsumable electrode arc melting of float zone purified molybdenum and high purity rhenium.
(11 : 00 a. m. ) MECHANICAL PROPERTIES OF VARIOUS Mo-Re ALLOYS
J. v/adsworth*, T. G. Nieh*, C. M. Packer', ana J. J. Stephens** * Metallurgy Department, Lockheed Palo Alto Research Laboratory, Palo Alto, CA 94304 ** Sandia National Laboratory, Albuquerque, NM
87185
Molybdenum alloys containing Rhenium are candidate alloys for nuclear reactor applications. The microstructures and mechanical properties of a range of experimental and commercial Mo-Re alloys will be described. In particular, a comparison of the tensile properties of conventional Mo alloys such as unalloyed molybdenum and Titanium-Zirconium Molybdenum (TZM) will be made wi th the Mo- Re alloys.
Sponsored by TMS Refractory Metals Committee Tuesday. March 4,1986 8:30 a.m.
Iberville Marriott Hotel Session Chairman: R. H. Cooper, Jr., Oak Ridge Nat. Lab., P.O. Box X, Oak Ridge, TN 37831
(11:25 a.m.) A CONSUMABLE ARC-MELTING, EXTRUDING, AND ROLLING PROCESS FOR IRIDIUM SHEET: R. L. Heestand, M. M. Martin, and G. L. Copeland, Oak Ridge National Laboratory, Oak Ridge, TN 37831 Abstract Not Available
(8:30 a.m.)
SOLID AND LIQUID MIXTURES I
COMPARI SON OF NlOB I UM (COLUMB IUM) ALLOYS FOR SP-100 SPACE REACTOR APPLICATION: M. Kangilaski, General Electric Company, Sunnydale, CA 94088 Abstract Not Available
(8:55 a.m.)
Sponsored by the TMS Solidification Committee Tuesday. March 4, 1986 8:30 a.m. Session Chairman: R. Philadelphia, PA 15069
D.
Doherty.
Bacchus Marriott Hotel Drexel University,
ANALYSIS OF CREEP DATA FOR REFRACTORY ALLOYS FOR SPACE REACTOR APPLICATIONS: J. A. Horak, H. E. McCoy, and R. W. Swindeman, Oak Ridge National Laboratory, Oak Ridge, TN 37831 Abstract Not Available
(9:20 a.m.) CREEP PROPERTIES OF PWC-ll BASE METAL WELDMENTS AS AFFECTED BY HEAT TREATMENT: R. H. Titran and T. J. Moore, NASA-Lewis Research Center, Cleveland, OH 44135 Abstract Not Available
(8:30 a.m.) THE EQUILIBRIUM MORPHOLOGY OF SOLID-LIQUID MIXTURES AT LOW LIQUID VOLUME FRACTIONS: Hyo-Hoon Park and Duk N. Yoon, Department of Materia 1s Science and Engi neeri ng, Korea Advanced Institute of Science and Technology, P. O. Box 150, Chyungyangni, Seoul, Korea. The equilibrium shape of grains surrounded by liquid of low volume fractions is descri bed in terms of the condition that the sum of
TMS Annual Meeting 61 various interfacial energies is mlnlmum. The interfacial energies are a ssumed to be i sotropi c. At hi gh 1 i qui d vo 1 ume fractions the gra i ns are spheri ca 1; as the 1 i qui d vol ume fraction decreases, the grains become anhedral approaching polyhedral shape. The grain shape can be a 1 so descri bed in tenns of a ba 1 ance between the sphering force of the grains and the liquid pressure arising from the menisci at the specimen surface. The results of the analysis are compared with the observed morphological changes during 1 iquid phase sintering. If the chemical equilibrium of the solid-liquid mixture is altered by either changing the composition or the temperature, migration of sol id-l iquid interfaces can occur, causing a sUbstantial deviation from the equilibrium shape.
phases can cause material s to creep at greatly enhanced rates and reduce their creep ductil ity. Liquid effects on creep have been observed in a wide variety of materials, including metals, ceramics, and geological material s. Recent studies in our 1aboratory have been di rected at understanding the mechani sm by which the liquid affects the creep deformation process. A number of model materials have been investigated, including porous alkalai halide salts with various liquids in their porosity and several metallic alloys containing low melting grain boundary phases. Results from these studies are presented and discussed.
(9:05 a.m.) MIGRATION OF SOLID-LIQUID INTERFACE INDUCED BY TEMPERATURE CHANGE: Stephen Hackney, Center for Materials Science, National Bureau of Standards, Gaithersburg, MD 20899, Young-Joon Baik, Korea Advanced Institute of Science and Technology, Seoul, Korea, Duk N. Yoon and John R. Manning, Metallurgy Division, National Bureau of Standards, Ga i thersburg, MD 20899.
TECHNIQUES FOR CHARACTERIZATION OF METALLIC AND CERAMIC POWDER AND SURFACES Sponsored by the TMS-AIME Powder Metallurgy Committee Tuesday. March 4. 1986 Mardi Gras K 8:30a.m. Marriott Hotel Session Chairmen: R. V. Raman, GTE Laboratories, Inc. Ceramics and Metallurgy Technology Center, 40 Sylvan Rd. Waltham, MA 02254; I. Anderson, Code 6321, Na Research Laboratory, 4555 Overlook Ave. S.W., Washington DC 20375
When 80Mo-20Ni powder mixtures are liquid phase sintered at 1500·C, Mo-rich grains of nearly spherical shape are produced with their composition in equilibrium with the liquid matrix. Most of the grains are separated from their neighbors by liquid films, but grain boundaries also exist between some grains. If the sintered specimens are heat-treated at a lower temperature (1390·C), the liquid films and grain boundaries are observed to migrate. The new solid solution fonned behind the migrating interface has an equil ibrium composition at the heat-treatment temperature as indicated by quantitative EPMA/EDS measurements. Because of the retrograde solidus, liquid droplets fonn at the grain boundaries. These droplets are observed to migrate with the grain boundary, acting as sinks for Ni atoms. Similar interface migration is observed in liquid phase sintered Co-Cu alloys.
* Research
supported by the National Science Foundation.
(8:30 a.m.) AN OVERVIEW ON THE CAPABILITIES AND LIMITATIONS OF PARTICLE SIZE CHARACTERIZATION TECHNIQUES, D. S. Parsons, GTE Products
Corporation, Hawes Street, Towanda, PA
(9:40 a.m.) THE STABILITY OF MIGRATING LIQUID FILMS: P. W. Voorhees and R. J. Schaefer, Metallurgy Division, National Bureau of Standards, Ga ithersburg, MD 20899. At elevated temperatures near the bulk solidus temperature, a thin liquid film forms at the grain boundaries of a polycrystalline alloy. When such a boundary migrates, as it will under the influence of curvature or temperature gradients, it leaves behind a modified mi crostructure. The microstructure generated by the moving 1 iquid film depends primarily on the stabil ity of the sol idifying interface. In experiments perfonned using a 2024 aluminum alloy in which a temperature gradient caused boundary migration, the solidifying interface was cellular, while in a succinonitrile-acetone alloy the solidifying interface was less unstable but one could observe a droplet shedding process from the freezing interface as the film migrated. A detailed calculation of the stability condition for migrating liquid films has been performed. The calculation i.s in reasonable agreement with experiment. The experimental results along with the theoretical predictions will be presented.
(10: 15 a.m.)
Break
(10:30 a.m.) DETECTION OF LIQUID PHASES IN BRASS AND DENTAL ALLOYS WITH THE PUCOT: A. Wolfenden and M. R. Harmouche, Mechanical Engineering Department, Texas A&M University, College Station, Texas 77843. An ultrasonic method known as the PUCOT (piezoelectric ultrasonic composite oscillator technique) has been used to detect small quantities of liquid formed in solids on heating via the influence of the liquid on the elastic modulus and mechanical damping of the system. The apparatus is described and then three examples of investigations are presented: the melting and redistribution of lead in free-machining brass near 327°C; the presence of Hg near 70°C in Ag-Hg-Sn amalgams; and the formation of the Al-Si eutectic in a porcelain/gold alloy interface.
The characterization of metal powders by particle size distribution can be very important in the powder' 5 use. An overview is presented, containing, in the author's experience, some appropriate and not so appropriate measurement techniques. Problems which may be encountered, as well as suggestions for use of the resulting data will be -discussed.
(9:00 a.m.) SURFACE CHEMISTRY AND SIZE ANALYSIS OF FINE AGGLOMERATED CERAMIC POWDERS, A REVIEW: M. Kahn. Code 6360, Naval Research Laboratory, Washi ngton, DC 21!375':'dnd R. Chanchani, AT&T, Bell Laboratories, Allentown, PA 18105. Mi cron size and submi cron powders used to prepare advanced ceramics have high surface curvatures and therefore exhibit high interparticle forces. This can result in strong agglomeration tendencies that impede the densification of green compacts. This presentation is a review of liquid suspensions that are used to control these phenomena and that allow maximum homogenization of multiconstituent formulations. The surface chemistry of these powders controls the interfacial forces between the powders and methods to measure and adjust these parameters in aqueous suspensions will be discussed. They will then be applied to attain meaningful determinations of agglomerate size and strength. (9:30 a.m.) CHARACTERIZATION OF POWDERS FOR STRUCTURAL CERAMICS: S. Natansohn, GTE Laboratories, Inc., 40 Sylvan Road, Wa ltham, MA 02254 one use of ceramics as structural components demands materials of the highest quality and this, in rurn, poses stringent requirements on the properties of the starting powders. The abil i ty to defi ne, characteri ze and measure these properti es is essential, not only to the development of such materials, but also to assure their continued quality in production. This paper reviews the techniques for the characterization of the sUb-mi cron cerami c powders, wi th parti cul ar emphas i s on silicon nitride. Specifically, it discusses methods for the determination of a. phase purity; b. composition, both bulk and surface; c. impurities; and d. physical properties such as surface area, particle size distribution and particle morphology. An assessment of the extent to whi ch specifi c powder characteri sti cs affect the properti es of the resulti ng cerami cs is presented. (10:00 a.m.)
(11:05 a.m.) CREEP OF SOLIDS CONTAINING LIQUID PHASES:* G. M. Pharr, B. L. Vaandrager, and P; S. Godavarti, Department of Materials Science, Rice University, Houston, Tpxas, 77251; T. G. Nieh Lockheed Palo Alto Research Laboratory, 0-9310, B-204, 3251 Hanover Street, Palo Alto, CA 94304. The creep behavi or of so 1 ids conta i ni ng 1 i qu i d phases is often very different from that of entirely solid materials. Liquid
18848
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(10: lOa .m.) THE CHARACTERIZATION OF FINE METAL POWDERS USING A CENTRIFUGAL
PARTICLE ANALYZER:* R.M. Allen, Sandi.q National Li vermore, CA, 94':550 A
~park
ero~ion
variou~ m~tal1ic
Laboratorie~.
device is being u~ed to produce fine powder~ of elements. The de,gired particle size is near the
62 TMS Annual Meeting lower limits of capability of most commercially-available particle size analysis equipment. However, a centrifugal particle size analyzer has been obtained which is claimed to allow the determination of particle distributions with a lower size limit of 20 nm. Initial results obtained with this device indicate that measurements of size distributions can be obtained for the fine spark eros ion powders with generally good reproduc i b iIi ty. Work
is under way to establish the accuracy of these distributions with pi3.rticle counting using an automated scanning electron microscope
and scanning transmission electron microscope.
The results of
this comparative study will be described, together with general observations on the relative merits and drawbaCks of the two analytical approaches. *Thi:3 work supported by the U.S. Department of Energy, DOE, under
contract number OE-AC04-76oP00789.
(10:30 a.m.) TECHNIQUES FOR CHARACTERIZING AS-ATOMIZED ALUMINUM ALLOY MICROSTRUCTURES: S. D. Kirchoff and W. M. Griffith, Air Force Wright Aeronauti~ Laboratories, Materials Laboratory, AFWAL/MLLS, Wright-Patterson AFB, OH 45433 and Young-Won Kim, Metcut-Materials Research Group, P.O. Box 33511, Wrightterson AFB, OH 45433
(8:50 a.m.) THE ATTAINMENT OF VERY LARGE UNDERCOOLINGS IN SUBMICRON Al-Ge POI-JOERS AND ITS IMPORTANCE IN NON-EQUILIBRIUM SOLIDIFICATION M. J. Kaufman, National Bureau of Standards, Gaithersburg, MD 20899, H. L. Fraser, University of Illinois, Urbana, IL 61801 Conventionally, undercooling studies have been performed on small droplets (1-10 ~m in diameter) in order to minimize the number of heterogeneous nucleation sites and thereby, approach homogeneous nucleation conditions. Recently however, techniques have been developed for producing submicron size powders the results of which have been corresponding increases in attainable undercooli ngs. In thi s study, the undercoo 1 i ng of submi cron Al-Ge powders has been studied directly in a transmission electron microscope. By employing a microscope heating stage the undercool ings prior to nucleation were measured and found to be Significantly greater than those reported previously. In addition, the effect of . cool ing rate on undercool ing was determined by using the electron beam as a heating source to melt individual particles and then quenching the molten droplets at different rates to preset substrate temperatures. The various microstructures which developed in these alloys will be discussed in terms of undercool ing both before and after the onset of nucl eation. (9;10 a.m.)
is difficult to study the fine microstructural changes that Jr in aluminum alloy powders between atomization and consolidation. The powder particles themselves are typically less than 20 microns in diameter making direct TEM thin foil preparation impossible without prior consolidation which results in a modified microstructure. Two techniques for preparing thin foils for TEM observation of as-atomized microstructures will be presented. The first involves embedding the powders in a nickel foil using an electrolytic deposition process. The second technique is an adaptation of the ultramicrotomy process. used routinely for the preparation of biological specimens. A stepby-step description of both processes will be presented and examples of results for lOOO-series and AI-Fe-Ce powder alloys 1 be discussed.
ELECTRON MICROSCOPY OF RAPIDLY SOLIDIFIED AND UNDERCOOLED IRON ALUMINlDE ALLOYS. S. A. Myers, C. C. Koch, Materials Enqineering, Box 7907, Raleigh, NC 27695-7907. J. A. Horton, Metals and Ceramics Division, Box X, Oak Ridge National Lab., Oak Ridge, TN 37830.* Iron aluminide alloys (Fe(Ni, Mn)-Al-C) produced by rapid solidi fi ca ti on will be compa red to samples under coo 1ed in the drop tube at Marshall Space Flight Center, Huntsville, Alabama. A piston and anvil (arc-hammer) device is used to produce rapidly solidified samples which have been shown to have metastable L12 structures. Undercooled samples were heated, dropped, undercooled and experienced containerless solidification in an inert atmosphere at the drop tube. Very high interface velocities are achieved in rapidly solidified and undercooled samples but the heat transfer mechani sms are very different. The effect of these two techniques on the microstructure was studied using scanning transmission electron microscopy. *Supported by NASA grant NAG8-475 (S.A.M., C.C.K.) and SHaRE program under contract no. EY-76-C-05-0033 with the Oak Ridge Associated Universities (S.A.M., C.C.K., J.A.H.). (9:30 a.m.)
UNDERCOOLED ALLOY PHASES III Sponsored by the TMS Alloy Phases Committee Tuesday, March 4,1986 Mardi Gras E Marriott Hotel 8:30 a.m. Session Chairman: D. E. Polk, Office of Naval Research, ONR Code 431,800 N. Quincy St., Arlington, VA 22217
CRYSTALLIZATION BEHAVIOR OF A MELT-SPUN Fe-Ni BASED STEEL: G.M. Michal and V. Laxmanan, Dept. of Metallurgy and Materials - Science, Case Western Reserve Univ., Cleveland, OH 44106, and T. K. Glasgow, Metal Science Branch, NASA Lewis Research Center, Cleveland, OH 44135. Whether Fe-Ni based alloys sol idify with a BCC or FCC structure has been Observed by many investigators to be a stronger function of kinetics and undercool ing than strictly free energy minimization. Such behavior has been observed in an Fe based alloy containing 33 Ni, 2 Al, 6 Ti, 2 B by wt. 7.. The alloy was cast as a ribbon "'40 urn thick using a dual "free-jet" variation of chill block melt spinning against a Cu wheel. Optical, X-ray, and electron analyses of the as-cast and annealed ribbons were performed. A microstructure containing at least four layers comprised of FCC, BCC, or mixed FCC and BCC structures was observed in the as-cast-ribbon. The mid-thickness 1ayer had the most unusual features containing FCC grains'" 75nm in size encompassing spherulitic regions as large as 15 urn comprised of FCC grain "'25 nm in size. The crystall ization sequence responsible for the as-cast microstructure will be discussed in terms of undercooling, recalescence and variable cooling rates. (9:50 a.m.)
Break
(8:30 a.m.)
(10:00 a.m.)
GROWTH OF THE SOLID PHASE IN THE PRESENCE OF A LIQUID MISCIBILITY GAP FOR HIGHLY UNDERCOQLED SINGLE PHASE LIDUID ALLOYS: D.C. Van Aken and H.L. Fraser, Dept. of ~tallurgy, Univ. of 1111n01s, IIrbana, IL 61R01, and S.J. Ridder, National Bureau of Standards, Gaithershurg, Mn 20899.
UNDERCOOLED AND RAPIDLY QUENCHED Ni-Mo ALLOYS, S. N. Tewari and T. K. Glasgow,NASA-Lewis Research Center, 21000 Brookpark Rd., Cleveland, OH 44135.
The evolution of microstructure, as related to prior liquid undercooling, for rapidly solidified Al-Be and Al-In alloys will be presented. For Al-Be alloys, with low undercooling in the incipient liquid, solidification begins with the cooperative growth of a-Al and hcp Re. For higher values of undercool ing, the microstructure exhibits a change in morphology from a rod eutectic to that of a random di stribution of hcc Be spheres. The change in microstructure is related to a metastable phase diagram involving a liquid miscibility gap. For undercool ed monotect i c all oys, thermodynami c s requi res either a prior liquid-liquid phase separation or the simultaneous formation of the second liquid if the solid is to form. Experimental evidence for this phenomenon will be presented for the Al-In system.
Ni -Mo alloys were undercoo 1ed in both e 1ectromagneti c levitation (at M.LT.) and differential thermal analysis equipment. After thermal cycling undercoolings as great as 160 0 K were attained. The rate of recalescence depended upon the degree of initial undercooling and the nature (faceted or nonfaceted) of the primary nucleating phase. For comparison alloys of the same compositions were rapidly quenched by chill block melt spinning. Extension of Mo solid solubility from 28 to 37.5 a/o indicated effective quenching. Comparison of microstructures and microsegregation patterns showed distinct differences between rapidly solidified structures attained by pri or undercoo 1i ng and by rapi d quenchi ng. Di ffi culty in nucleating the F.e.C. phase was observed in rapid quenching but not in undercoo 1i ng. Dr. Tewari acknowledges the support of the National Research Counci 1 .
TMS Annual Meeting 63
(10:20 a.m.) A STUDY OF ALTERNATIVE CRYSTALLIZATION PHASES IN SUB-MICRON SPHERES OF IRON-NICKEL ALLOYS:* Yeon-Wook Kim and Thomas F. Kelly, University of Wisconsin, 1500 Johnson Dr., Madison, WI 53706 Three iron-nickel alloys (30, 40, and 50 wt% Ni) have been processed in vacuum by el ectro hydrodynami c a tomi za t ion to produce sub-micron spheres. This experimental geometry minimizes the possibil ity of heterogeneous nucleation. Transmission electron microscopy is used to determine crystal structure, composition, and microstructure of the solidified particles. The alternative crystall ization phase, BCC, is found in the 30 and 40 wt% alloys. The 50 wt% alloy is found to crystall ize as FCC only. Both of these findings are in accordance with predictions of a model of alternative crystall ization phase nucleation. In addition, an FCC phase is found in some of the 30 and 40 wt% alloys and its origin is considered. Furthermore, about one-fourth of the smaller droplets (less than 40 nm diameter) are found to be amorphous. *This work was supported by the Department of Energy, Office of Basic Energy Sciences, under contract Number DE-FG02-85ER452l5.
TUESDAY PM
ALTERNATE ALLOYING FOR ENVIRONMENTAL RESISTANCE IV: Oxidation Session I Sponsored by the TMSIMSD Corrosion and Environmental Effects Committee Tuesday, March 4,1986 Mardi Gras L-M 2:00 p.m. Marriott Hotel Session Chairmen: Chi-Meen Wan, Department of Materials Science and Engineering, National Tsing Hua University, Hsinchu, Taiwan, R.O.C.; and S. K. Banerji, FerroaIIoys Division, Foote Mineral Company, Exton, PA 19341
(10:40 a.m) UNDERCOOLING AND NUCLEATION IN IRON NICKEL ALLOYS. D. H. Rasmussen and K. Javed, Dept. of Chemical Eng _, Clarkson University, Potsdam NY 13676
Pure iron, pure nickel and iron-nickel alloys have been underroaled a rraximum of 0.25 'I'm (actual ITBximum observed under-coolinga varied from 440 degrees for pure iron to 420 degrees for a 58 w/o nickel alloy). The dispersion of the preformed and surface trea ted rretal p::>wders in a ceramic na trix tas penni tted large me ta 1 drople t undercool ing and con trol of the drople t un-
derccx>ling through surface ctEmistry.
(2:30 p.m.) TENTATIVE TITLE I NFLUENCES OF ALLOY I NG ELEMENTS ON THE HIGH TEMPERATURE OX IDA TI ON OF Fe-AI-Mn-C ALLOYS: Chi-Meen Wan, et al., Department of Materials Science and Engineering, National TSing Hua UniverSity, HSinchu, Taiwan, R.O.C.
Even though these un-
dercoolings exceed the clasical 0.2 Tm limit for homogeneous nucleation, the nucleation event is not likely to be ho['['K)geneous in origin becaslle of the imp:>rtance of droplet surface chemistry on determining the undercooling. The droplets crystallized into the FCC structure of the equilibrium alloys. The temperature of nucleation mirrors the liquidus curve in composition dependence. This betavior is explained with a thermodynamic model of nuclea-
tion in regular sol utions.
(ABSTRACT NOT AVAILABLE)
(2:55 p.m.) TENTATIVE TITLE MORPHOLOGICAL DEVELOPMENT OF OXIDE SCALES FORMED DURING HIGH TEMPERATURE OXIDATION OF Fe-Mn-AI BASE ALLOYS: Chi-Meen Wan, et aI., Department of Materials Science and Engineering, National TSing Hua UniverSity, Hsinchu, Taiwan, R.O.C.
(11 : 00 a. m. ) STUDIES OF UNDER COOLING IN THE IRON-CARBON-SILICON SYSTEM: William Oldfield, Materials Research & Computer Simulation Corp., Santa Barbara, CA 93110 and Alan J. Markworth, Battelle, Columbus Laboratories, Columbus, Ohio 43201.
(ABSTRACT NOT AVAILABLE)
(3:20 p.m.) 0
Studies of the stable and metastable phase diagrams for the FeC-Si system are described. These studies involved solidification at varying rates of heat removal, coupled with thermal analysis, as a means of inferring the equilibrium eutectic temperatures for the two diagrams. Heating experiments, in the region between the two diagrams, were conducted in which melting of the metastable phase and re-solidification of the stable phase were used to confirm the measured temperatures.. The kinetics of solidification in this system are next discussed, in relationship to the practical considerations which govern in which system solidification actually takes place. Finally, the concepts used in this work are related to studies in other systems and to other experimental work.
(11 : 20 a. m. ) RAPID SOLIDIFICATION OF UNDERCOOLED MELT DROPLETS OF AN ALUMINUM ALLOY AI-5.7%Fe-6.l%Ni: Young-Won Kim, Metcut-Materials Research Group, P.O. Box 33511, Wright Patterson AFB, OH 45433 and F. H. Froes, Air Force Wright Aeronautical Laboratories, Materials Laboratory, AFWAL/MLLS, Wright-Patterson AFB, OH 45433 A hypereutectic aluminum alloy Al-5. 7Fe-6 .IN! was studied to characterize the sequence of rapid solidification during atomization. Both homogeneous and heterogeneous nucleations were observed, with the former event in fine «lOllm) alloy droplets that are undercooled more than 30 0 K below the eutectic temperature (Te). The homogeneous nucleation is followed by planar solidification (PS) which gradually becomes morphologically unstable as, with recalescence, the solidification rate decreases and the diffusive velOCity of solutes in the liquid increases. A fine-scale cellular solidification (CS) develops, eventually transforming to coupled eutectic growth. After solidification both PS and CS regions contain extremely fine «25nm) compounds (AI FeNi), which apparently precipitate during 9 solid-state cooling. The whole process of solidification in both events is expUlined in terms of undercooling and non-equilibrium phase relations.
Extractive Metallurgy Lecture and Luncheon See Page III
OXr:J\TION OF A Fe-Mn-Al-C ALLOY AT 1000 C : M.F.Silva Lopes anu F.C Rizzo Assuns:ao, Department of Materials Science and Mettallurgy, PUC!RJ, Rio de Janeiro, R.J. 22.453, BRAZIL Austenitic stainless steels based on Mn and Al have been considered as an interesting alternative to the Ni and Cr based alloys due to the high cost and external dependence associated with these two metals. The behavior of a Fe-Mn-AI-C alloy during oxidation at 100aoe was investigated in atmospheres of air, nitrogen, argon, oxygen and vacuum of 5 x lO-4 atrn • Substitution of Al for Cr was expected to preserve the oxidation resistance of the alloy. In nitrogen rich atmospheres the behavior of the alloy was unsatisfactory. The poor oxidation resistance was correlated with an intense precipitation of AlN in the underlying matrix, which removed the Al from the solution, leaving the alloy unprotected. In atmospheres containing low pressure N2 the oxidation resistance of the alloy was very good, probably due to the formation of aluminum oxide on the surface. The thermodynamic stability diagram at IOaOoC for the Fe-Mn-AI system in an atmosphere containing 02 and N2 was used in the discussion of the experimental results.
(3:55 p.m.) I SOTHERMAL OX I DA TI ON BEHAV lOR OF FeMnA 1 ALLOYS AND COMPARI SONS WITH TYPE 304 STAINLESS STEEL: J. E. Flinn, G. R. Smolik, and D. V. Miley, EG&G Idaho, Inc., P. O. Box 1625, Idaho Falls, ID 83415 Isothermal tests in flowing dry oxygen have been performed on three alloys. Two of the alloys were FeMn(30-33%)Al(8-9%), one with I. 5 Wt% Si and the other with 0.1 wt% Si. The third alloy was an AISI Type 304 stainless steel. Continuous weight change measurements were recorded within the temperature range of 700 to 900'C for durations up to 800h. The results showed that the FeMnAl alloy with 0.1% Si had the largest weight gain per area of the specimen for all test temperatures. This alloy was also most susceptible to oxide scale spalling during controlled cooling. The FeMnAl alloy with 1.5% Si showed less weight gain/area, but the gain was markedly larger than for the AISI Type 304 stainless steel. Kinetic formulations associated with oxidation behavior are presented and compared for the three alloys, along with SEM/EDS analysis of the oxide scales.
64 TMS Annual Meeting (4:20
(3:40
p.m.)
HIGH TEMPERATURE OXIDATION KINETICS OF IRON BASED ALLOYS
CONTAINING A DISPERSED PHASE: S-W. PA.rk, Grad. Student - Metal., The Penna. State Univ .• 207 Steidle Bldg., Univ. Park, PA, 16802, G. Simkovich, Prof., The Penna. State Univ., 206-B Steidle Bldg., Univ. Park, PA
16802.
Iron based alluys containing vnrious concentrations of Cr and other alloying elements were tested in oxygen over a range of temperatures (1173-1373K) with a range of concentrations of a dispersed phase. The oxiclation resistance of a number of these a.lloys was found to be as resistant or more resistant as many complex super alloys such as the MeCrAIY a11oys. It was also found that the alloys displayed the maximum resistance at essentially a unique concentration of both Cr and the dispersed phase. Additionally, an unusual temperature effect was determined in a number of the alloys in that the resistance increased as the temperature increased. Finally, it was also determined that the alloys displayed little spalling in thermal cycling tests. It, therefore. appears that alloys have been developed which exhibit desirable properties with Cr contents considerably less than in presently utilized alloys.
p.m.)
SURFACE ACTIVE DELIQUORING AGENTS FOR ALUMINA TRIH¥DRATE,
Brian K. Failon, Nalco Chemical Company, 1601 W. Diehl Roao., Naperville, Illinois 60566 The use of chemical additives as deliquoring agents for alumina trihydrate, as produced in the Bayer Process, has recently become an acc~pted concept by alumina producers. Such reagents provide lower trihydrate filter cake moistures which results in reduced calcination costs, and also reduced soda levels in the trihydrate,which leads to improved product quality and greater caustic soda recovery. This paper deals with the mechanisms by which surface-active agents function as deliquoring agents. The principal focus is on the surface modifications at the air/liquid and solid/liquid interfaces, induced by adsorption of the surfactant components. The ultimate performance of such reagents is also related to such process parameters as filter VaCUum, temperature, trihydrate particle size, etc. A cursory discussion of potential benefits of deliquoring agents is included, as evidenced by extensive plant experiences.
(4:00
p.m.)
INSTRUMENTED OVERPRESSURE PROTECTION FOR BAYER PLANT PRESSURE
ALUMINA AND BAUXITE IV Sponsored by TMS Light Metals Committee Tuesday, March 4, 1986 Pontchartrain Ballroom A 2:00p.m. Sheraton Hotel Session Chairman: D. B. Salt, Alcan Smelters and Chemicals Ltd., P.O. Box 6090, Montreal, Canada H3C 3H2
ICTION OF HEAT EXCHANGER - HEAT TRANSFER COEFFICIENT DECAY TO FOULING: G. A. O'Neill, Alumina and Chemicals Division, coa Techni ca 1 Center, Alcoa Center, Pennsyl vani a 15069. reduction over time of the overall heat transfer coefficient n Bayer process tubul ar heaters due to DSP foul i ng is iscussed. A mathematical heat transfer model of this problem as been developed. The model is in a general form allowing for he use of different kinetic equations for the OSP formation reaction. Liquor-side heat transfer coefficients are calculated from correlations using the liquor physical properties. Steamside heat transfer coefficients are calculated using a Nusselttype equation. The heat transfer model predictions are compared to experi menta 1 results.
(3:00 p.m.) New Slurry Pump Mechanical Seal:
J. A. Monnot, P. O. 80
337, Gramercy, LA 70052, Robert S. Wentworth, 27941 Fron St., Rancho, CA 92390. Slurry pump glana water is eliminated with the use of a ne, mechanical seal design, resulting in reduced operatmg costs The seal is suited for operation in caustic, abrasive, higl saturated, and scaling fluids. The seal is easily installed ir existing pumps and has given excellent service even wher subjected to conditions of poor shaft to case alignment, cavitation, and extreme radial whip of the rotating assembly, The seal employs an elastomer ring to serve as both sprine and secondary seal and has no sliding fits to clog or jam. The rotating face seats against a surface which is unlikely tc be out of true, relative to the bearing axis, regardless of thE pump condition. The stationary face adapter permits the face to freely align with this true running seal face. The usefulness of the seal is enhanced by an innovative mounting assembly designed to simplify installation and maintenance procedures, to allow external adjustment while the pump is running, and to allow impeller seal clearance adjustment without affecting seal setting.
(3:20 p.m.) Modification of Horizontal Table Filters to Decrease the Moisture Content of the Cake Christian Tremblay, Aluminum Company of Canada Ltd., P.O. Box 1500, Jonquiere, Que., Canada 97S 4L2 The arrangement of the feed and wash lines was modified to decrease the moi~ture content of the cake: The feed pipe was shortened and placed closer to the blow-back ared; the cloth wash was relocated; the cake wash was moved I and the fi1 ter valve modified accordingly. Better cake distribution and more efficient use of filter area led to a decrease of 2-3% in the moisture content of the cake: 6-8% moisture is now obtained consistently.
VESSELS: D.L. Puxley and P.F. Bagatto, Alcan Smelters and Chemicals Ltd, P.O. Box 1500, Jonquiere, Que., Canada, G7S 4L2 The single most serious problem in using conventional pressure relief systems in Bayer process digestion circuits. is the formation of a rock like scale deposit on all wetted surfaces. Digesters, heaters and all interconnecting piping is subject to this scale formation. As a result, relief valves and rupture discs will be rendered totally or partially inoperative. The safety device may fail to relieve at the set pressure or the relief capacity may be greatly reduced due to scale formation. This paper presents an instrumented over-pressure protection system that has been in operation for several years and that has received approval in principle from the Provincial Government.
(4:20 p.m.) MUD DISPOSAL AT THE BURNT ISLAND ALUMINA PLANT: SA ChemicaLs Limited, SurntisLand, ScotLand.
B. G. PurneLL.
This paper describes the method of mud disposaL used at the SurntisLand ALumina pLant since 1942. Red mud from the rotary vacuum filters, at 60% solids, is transported by road to an inland tipping site using speciaLLy seaLed trucks. The mud is tipped into a natural depression in the topography some 2 Km from the factory previousLy occupied by an oil shaLe mine. r·iud is tippee:: tv 6 j"j,uiC1;;;UI01 depth c..f 25m into ,In ore.:: :::;Ci.:C 12QO~ Long by 200m wide. The mud is contained by embankments formed from burnt oiL shale. The trucks transport the material to the tipping site aLong pubLic roads and then to the tipping bench across a Layer of red sand laid on top of the recently tipped mud. The tipping sequence across the bench is carefuLly controlLed to maximise the stabiLity of the tip and maintain the design slope on the tipping face. Drainage from the tip area is coLLected and returned to the factory site.
(4:40
p.m.)
RETROFITTING CONVENTIONAL MULTIDECK THICKENER-CLARIFIERS INTO
HIGH RATE THICKENERS: P.F. Bagatto and D.L. Puxley, Alcan Smelters and Chemicals Ltd, p--:-O:-B-;x 1500, Jonquiere t Quebec, Canada, G7S 4L2 This paper describes the techniques used to retrofit the existing conventional multideck thickener-clarifiers in the mud washing circuits into high rate thickeners using synthetic flocculants. One stage of mud washing has been already retrofitted at each of the two Bayer Plants with excellent results, well beyond original expectations. At a small capital cost one counter current washing stage was retrofitted to make the most efficient use of today's synthetic flocculants. The results show that we were able to decrease the settling area requirements by a factor of 12 and at the same time increase the underflow percent solids by 50% while maintaining good clarity in the overflow.
TMS Annual Meeting 65
CARBON TECHNOLOGY IV Sponsored by the TMS Light Metals Committee Pontchartrain Ballroom C Tuesday, March 4,1986 Sheraton Hotel 2:30p.m. Session Chairman: Jean-Paul Huni, Alcan International Limited, P.O. Box 1250, Jonquiere, Quebec, Canada G7S 4K8
(2:30 p.m.) COAL TAR PITCHES FROI·1 COAL TAR DISTILLATES: Dr. Henry Kremer and Mr. Samuel Cukier,. Domtar Inc./Chemical Group/Organlc Chemicals Division, 1136 t1atheson Blvd., Mississauga, Ontario, L4,1 2V4, Canada. The polycondensat i on of aromati c compounds duri ng di st ill ati on was enhanced by catalytic dehydrogenation. The changes in molecular weight of the precursor were followed by GPC. A significant portion of compounds and their reactivity were determi ned by HPLC.
binder, free from coal tar pitch, the emanation of PAH from the anode can be significantly reduced. However, the paste must also ensure a uniform current flow from the different studs into the carbon. The baking characteristics must yield a homogeneous anode, free from cracks, cavities and points. This paper communicates the results in terms of workplace hygiene and operational performance, achieved in Rheinfelden ' s 90 kA VS-Soederberg electrolysis using a tar-free anode paste.
(4:35 p.m.) REDUC TI ON OF STUD CORROS I 011 IN VSS ANODES: Otto Behrman, Cindy Jones, John Johnson, Commom
(2:55 p.m.) FACTORS AFFECTING THE BAKE VOLUMETRIC CHANGES OF CATHODE RAMMING MIX: D. G. Brooks and A.L. George, Reynolds Metals Company, Reduction Laboratory, P.O. Box 1200, Listerhill, Alabama 35660. The shri nkage on baki ng of hot rammed cathode mi x was i nvestl gated to determi no the effect of varyi ng formul ati on and formi ng pressure. Green apparent density and shrinkage on baking both decrease with i ncreas i ng fi nes aggregate and decreas i ng pitch content. For a given formulation, the shrinkage on baking may be minimized by ramming to high pressure; however, equating high green density with low shrinkage does not hold true when varying the mix formulation: a dry mix results in both low density and low shrinkage. Other important properties of cathode seams as related to mix formulation were investigated alkali swelling, porosity, Taber wear index and thermal expans on. Tests indicate that a dryer mix may be used to reduce shr nkage without adversely affecting these properties.
(3:20 o.m.) PROUUCTION OF A NEW COl.D RAMMING PASTE WITH LOW LINEAR SHRINKAGE: A. Murgia, R. Foddi, S. Montesi, Aluminio Italia S.P.A., Casella Postale 51,09010 Portoscuso Sardinia, Italy. Production and optimization of a new cold ramming paste for electrolysis cells, the work, based on the research and the deve 1opment of optimi zed granul ometri cal di stri but i on and binder type, resulted in the production of a cold ramming paste with following characteristics: Low content of bi nder - Low baki ng wei ght losses - Hi gh resistence at sodium penetration low linear shrinkage, the product is actually used, with good results, in aluminia's 150 KA electrolysis cells.
CAST SHOP TECHNOLOGY AND RECYCLING IV: Vertical and Continuous Casting Sponsored by the TMS Light Metals Committee Pontchartrain Ballroom Tuesday, March 4,1986 Sheraton 2:30p.m. Session Chairman: John E. Jacoby, Alcoa Center, P A 15069
(2:30 p.m.) EXPANDING CAPABILITIES OF THE ELECTROMAGNETIC CASTING PROCESS (EMC) OF ALUMINIUM ALLOYS: Dr. J. C. Weber and Dr. R. Sautebin, Swiss Aluminium Ltd, Research and Development, 3965 Chippis, Swi tzerl and. After seven years of industrial production, the electromagnetic casting process has proven to be highly economical, reI iable and safe. Today worldwide more than 450,000 metric tons/year of EMC ingots mainly for can stock business are rroduced by the ALUSUISSE EMC process, and the production is rapidly growing. More recently the capabil ities panded for casting hard alloys (up to 85" wide). The savings alloys, which normally require
of this technology have been ex(2xxx, 7xxx) and larger sizes are especially high for hard deep scalping and wide trimming.
This paper is concerned with these more recent developments.
(2:55 p.m.) (3:45 o.m.) A TECHNIQUE FOR ME AS IN SITU CATHODE EXPANSION DURING ALUMINIUM ELECTROLYSIS: DavTifT. Newman, Harald Justnes, Ola T. Dahl, Sissel Kopperstad and Harald A. Oye: Institute of Inorganic Chemistry, Norwegian Institute of Technology, Universitetet i Trondheim, N-7034 TRONDHEIM-NTH, Norway. A differential method for precisely measuring the linear expans ion (or cont ract ion) of a cathode duri ng electro 1ys is of aluminium has been developed. Reproducable changes as small as 0.2%, over a 100 minute electrolysis, have been measured. Expansion of AUC-graphite and commercial cathode material are reputed.
(4: 10 o.m.) SOEDERBERG POT OPERATION WITH TAR-FREE PASTE: A. J. Franke Aluminium-Hutte Rheinfelden GmbH, Friedrichstrasse 80, 7888 Rheinfelden, West Germany; L. F'orster, Aluminium-Hutte Rheinfelden GmbH, Friedrichst.rasse 80, 7888 Rheinfelden, West Germany; A. Sturm, Aluminium-"Hutte Rheinfelden GmbH, Friedrichstrasse 80, 7888 Rheinfelden, West Germany; H. Kaiser, Aluminium-Hutte, Rheinfelden GmbH, Friedrichstrasse 80, 7888 Rheinfelden, West Germany
Workplace concentrations of polycyclic aromatic hydrocarbons (PAH) are of major concern in Soederberg potrooms. Using a
FLUID FLOW PHENOMENA IN CONTINUOUS ELECTROMAGNETIC CASTING : Ch. Vives and R. Ricou, Laboratoire de Magnetohydrodynamique, 001 vers 1 te d' Avi gnon, 84000 Avi gnon, France. The commercial value of circular and rectangular cross-section blocks cast in electromagnetic molds is dependent on the flatness of the ingot surface and the number of folds and pinholes per unit area of surface. An exact understanding of the role of the shield is necessary to eliminate these defects. The effects of the screen on the magnetic field distribution, the electromagnetic force field and the velocity pattern has been experimentally exami ned us i ng both a phys i ca 1 model (mercury pool) and under casting conditions on an industriel scale. Velocity measurements have been made within the sump using a newly developed magnetic probe. Experiments were carried out for various shapes, dimensions and locations of the shield. The evolution of the flow structures are eas ily understood by exami nati on of the e I ectromagnet i c force fi e 1ds.
(3:20 p.m.) HEAT TRANSFER MEASUREMENTS OUR I NG DC CASTI NG OF ALUM I NUM. PART I: MEASUREMENT TECHNIQUE: J. A. Bakken, T. Bergstrom, The Norwegian Institute of Technology, Dlvlsion of Metallurgy, N-7034 Trondheim, Norway. A method for determination of surface heat transfer to the cool ing water and mold based on in-situ temperature measurements
66 TMS Annual Meeting in the DC cast ingot has been developed. Three or more steel mantled coaxial thermocouples (0.5 mm diameter) are mounted on a wire frame called a "harpe." Allowing the "harpe" to freeze into the solid ingots during the casting time, temperature plots Tl(t), T2(t), T3(t) are obtained for three moving points positioned typically 3.7 and II mm from the ingot surface. From these measurements surface temperature, heat fl ux and heat transfer coefficients are computed as a function of vertical distance. The computer program is based on steady state twodimensional heat balances with convective terms for two fixed volume elements: one around thermocouple TI and one surface element. A special numerical smoothing procedure is incorporated. The heat of solidification is taken into account.
(3:45 D.m.) HEAT TRANSFER MEASUREMENTS OUR I NG DC CASTI NG OF ALUM I NUM. PART II: RESULTS AND VERIFICATION FOR EXTRUSION INGOTS: E. K. Jensen, S. Johansen, Elke" a/s, Mosal Aluminium, Lista Al umini umverk, P. O. Box 128, N-4551 Farsund, Norway; T. Bergstrom, J. A. Bakken, The Norwegian Institute of Technology, Division of Metallurgy, N-7034 Trondheirn, Norway. Measurements were carried out during ordinary production runs of DC hot top mold casting of extrusion ingots. Measured values cover the initial shell formation within the mold as well as direct water cooling zones/mechanisms below the mold. A separate two-dimensional mathematical casting model (Dystal) was then used to verify the measured heat transfer values. This was ained by using these values as input, recalculating observed perature time curves for selected points moving with the at. Al so cal cui ated and observed sump profi 1es were
strings of side dams which are moving at the same velocity as the sol idifying section. There are no major discontinuities in the mold, either across the width or length of section. Heat transfer is very rapid compared to other continuous casting processes; thus, casting speeds are suitable for entering the cast strip, directly into a tandem roll ing mill, at hot roll ing temperature. Hazelett's production work in the '60 ' s and '70 ' s. however,
revealed that areas of distortion of the mold belts caused liquation and segregation in the strip surface which rendered the product commercially unsuitable for hard alloys or special surface finishes. This paper reviews Hazelett's solution(s) to the belt distortion problem and our experiences during the last two years in continuously casting and in-line rolling aluminum alloys containing
~~a~~ i ~gs m~ms~~mc ~~gd; i a~~n~m~~i v/~g~~Tt ~~~a ~ms d~~g included.
mf"fj ng
COPPER, NICKEL, COBALT & PRECIOUS METALS IV: INNOVATIONS IN PRECIOUS METALS PROCESSES B Sponsored by the TMS Copper-Nickel-Cobalt and Precious Metals Committee Tuesday, March 4,1986 La Galerie 5 2:30 p.m. Marriott Hotel Session Chairman: S. D. Hill, U.S. Bureau of Mines, Salt Lake City Research Center, 729 Arapeen Drive, Salt Lake City, UT 84108 (2:30 p.m.) THE REACTIVITY AND EQUILIBRIA OF Au, Pt, Pd, Ir, Rh, Re, Mo AND W WITH CHLORINE: Arne Landsberg, U.S. Bureau of Mines, Albany Research Center, P. O. Box 70, Albany, OR 97321
IMPROVEMENTS OF ROLLING SLAB QUALITY BY D.C. CASTING WITH A NEW HOT TOP MOLD: W. Schneider, Vereinigte Aluminium-Werke AG, Georg-von-Boeselager-Str. 25, Bonn, Germany In addition to the successfully used VAW hot top casting technology for billets a hot top mold for rolling slabs was developed. The aim of this evelopment was to improve the slab quality with respect to shell zone and surface in order to reduce the scalping depth considerably or even to avoid scalping completely before rolling for some products. The present work introduces the new mold and shows the influence of the new casting technology on the slab parameters such as surface finish, shell zone formation incl uding surface segregation, cell structure and geometry of pure aluminium slabs. Furthermore first results of cast shop performance of thenewmold and costs will be discussed.
(4:35 p.m.) A FLUID MECHANICS CONSIDERATION OF THE ROLL CASTER TIP DESIGN CRITERIA: Ho Yu, Alcoa Laboratories, Aluminum Company of America, Alcoa Center, PA 15069, Daniel K. Ai, Alcoa Laboratories, Al umi num Company of Ameri ca, Al coa Center, PA 15069. Nonuniform molten metal temperature distribution across the width of the roll caster can create hot spots and consequently causes bleed out during high speed casting. Flow disturbances and separation caused by the internal support structures in the caster tip can also cause surface defects on the cast plate. To ensure uniform temperature of molten metal feed across the entire width of the roll caster, a flat molten metal velocity profile must be maintained throughout the caster tip. Fluid mechani c scans i derat i on and theoret i ca 1 ca 1cui at ions were used to determine the conditions necessary to maintain a flat molten metal velocity profile in the tip and minimize flow disturbances caused by the tip internal support structures. A water model was constructed to test the val idity of the theoretically establ i shed des i gn criteri a. Good agreements were found between theory and experimental results.
(5:00 p.m.) UPDATE ON CONTINUOIJS CASTING OF ALUMINUM ALLOYS BY THE TWIN-BELT PROCESS: Charles J. Petry and Wojtek Szczypiorski, Hazelett Strip-Casting Corp., P.O. Box 600, Colchester, VT 05446 In the Hazelett twin-belt process, the casting mold is defined by two thin substantially parallel steel bands, or belts, and two
The chlorides of precious and refractory metals have intriguing properties which often arouse the metallurgist's imagination. The ease of preparation, reactivity, and vo 1 at iii ty of these compounds makes them attract i ve as intermediates in the chain of processing and recovery. The Bureau of Mines, U.S. Department of the Interior, has investigated the formation and properties of these chlorides. This paper explores the kinetics and equilibria pertinent to the processing and recovery of gold, platinum, palladium, iridium, rhodium, rhenium, molybdenum, and tungsten with chlorine.
(2:55 p.m.) THE KINETICS OF GOLD CYANIDE ADSORPTION ON AN ANION EXCHANGE RESIN: J. B. Hiskey, University of Arizona, College of Mines, Tucson, AZ 85721 Much attention is currently focused on resin ion exchange as an a lternat i ve to the carbon- i n-pu 1 p (C I P) process for extracting gold from cyanide media. This paper describes the kinetics of extracting the aurocyanide complex from solution by an anion exchange resin. Adsorption rates were determined as a funct i on of temperature, free cyan i de, pH, and res in particle size. Equilibrium isotherms have been obtained for temperatures between 25 and 45 'C, and for initial gold concentrations ranging from 25 to 400 ppm Au(CN),. The equilibrium isotherms correlated well with the simple Freundl i ch equat i on. Loadi ng capac i ty decreases wi th increasing temperature, however, within the narrow range investigated adsorption rates appear to be insensitive to temperature.
(3:20 p.m.) BELT-PRESS FILTER APPLICATION IN CYANIDE MILL TAILINGS DISPOSAL: Allan Young, Larry Enloe and Brad Huff, Sunshine Mining Company, Silver Peak, NV 89045 Sunshine Mining Company's Sixteen-to-One Mill is a conventional cyanide plant utilizing counter-current decantation and Merrill-Crowe precipitation. Commissioned in 1982, this plant now processes 750 TPD of silver-gold are from underground mining operations. Since start-up, cyanide, together with tailings disposal costs, had represented a major portion of the total milling costs. High cyanide consumption was primarily a result of mechanical loss to tails due to unrecoverable moisture content in the deposited tailings and to high evaporation rates in the area. Significant tailings disposal costs were due to the requirement that the impoundment dike be constructed using compacted borrow material together with a clay liner on the up-stream side of the dike. Both of these costs were substantially reduced following the installation of a belt-press filter. This unit produces a stackable filter cake while returning more valuable solution to the mi 11,
(3:45 p.m.) TENNECO MINERALS - MANHATTAN PROJECT: C. A. Moore, Tenneco Minerals Co., P. O. Box 56, Manhattan, NV 89022 The Manhattan District was discovered in 1905. Minin9 activity continued until 1912, when the rich surface ores were exhausted. Tenneco acquired the property in 1981 and commenced exploration, metallurgical testing, and in 1983 resumed mining and milling. The paper describes the Tenneco operation including ore geology, mining, crushing and grinding, gravity concentrate circuit, flotation concentrate circuit, thickening, fi ltration, leaching, and product recovery.
(4:10 p.m.) WEAK AC I D DI SSOC IABLE CYAN I DE DESTRUCT! ON FROM WORK I NG CYAN I DE SOLUTIONS: P. R. Taylor, University of Idaho, Moscow, Idaho, S. E. Clay, Taylor Metallurgical Laboratory, Moscow, Idaho, and J. C. Lawrence, United States Antimony Corp., Thompson Falls, Montana Recent 1y env i ronmenta 1 regu 1at i on of cyan i de so 1ut ions discharge have changed in Idaho. One area of active interest is methods for the destruction of weak acid dissociable cyanide complexes. The results of a number of laboratory tests on solutions from the Yankee Fork Mine are presented. The field application of the laboratory results are also presented. A discussion of the practicality and economics of the various alternatives available is presented.
TMS Annual Meeting 67 transformatlon product. These combined effects act to stabilize the plastic flow, and can result in substantial enhancement of uniform ductility in austenitic and low-alloy ferrite-based steels. Critical experiments also reveal a noteworthy transformation-toughening effect in high-strength steels that fail by ductile shear localization.
(2:25 p.m.) THE FCC TO HCP TO BCC PHASE TRANSFOR'lATION SEQUENCE IN HETAST"",BLE FE-Ml,\l'-CR ALLOYS: Larry D. Thompson, Department of :,1echanica1
Engineering, San Diego State University, San Diego, CA 0191
92182-
Phase transformations in metastable austenitic Fe-Mn-Cr alloys are discussed. The FCC to HCP to BCC phase transformation sequence was studied for both the athennal and strain-assisted modes including nucleation events and resultant microstructural features. Mechanical behavior and fracture characteristics are correlated with alloy chemistry, phase stabilities and morphologies in the temperature range of -196 to 23C. Finally, a discussion is presented on possible mechanical design applications and methodologies for metastable materials. Their potential in unique applications such as solid-state energy absorhing devices to protect engineering structures during seismic act ivi ty, fail-safe magnetically-triggered mechani cal df'formation detectors for safety swi tches, and reinforcement mat erials for ultra-light vehicles is reviewed.
(2:50 p.m.) TRANSFORMATION TOUGHENING OF CERAMICS:
(4:35 p.m.) THE BARRICK MERCUR DUMP LEACH - TOOELE, UTAH: R. E. Brewer, Getty Mining Company, P. O. Box 838, Tooele, UT 84070 The Barrick - Mercur Mine is stockpiling sub-ore at a grade of .035 oz Au/ton ore and as much as three to four mi 11 ion tons may eventually be accumulated. The amenability of the ore lends itself to heap leaching; however, due to the mountainous terrain, a dump leaching approach is considered more practical. The initial concept utilizes the dump containment area as an internal pregnant liquor storage pond. Similarly, the barren solution will be supplied by the existing tailings area solution which is produced from the carbon-in-leach production plant in operation since 1983. Leach operation will require carbon adsorption to recover the gold. Two methods of carbon contact are anticipated in the early stages, one of which will utilize portable carbon adsorption units; however, the initial adsorption will be accomplished in the existing carbon-in-leach circuit. Start-up is anticipated in August 1985.
A. G. Evans, Department
of Materials Science and Mineral Engineering, University of California, Berkeley, CA 94720. A comprehensive review of toughening mechanisms in transformable brittle solids is presented. Primary emphasis is given to transformation toughening, although microcrack and deflection toughening are also considered. Models of toughness are developed using concepts from applied mechanics, but within the context of the thermodynamics and kinetics of the transformation process. The predictions of' the models are compared with experimerltal data for various Zr0 containing ceramic alloys. 2 I t is concluded that the predominant toughening mechanism depends on the alloy composition and microstructure; dilatational transformation toughening with shear modifications dominates in partially stabilized zirconia; uniaxial transformation and microcrack mechanisms prevail i0 zirconia toughened alumina; transformation toughening with partial reversibility predominates in tetragonal zirconia polycrystals.
(3: 15 p.m.)
EARL R. PARKER SYMPOSIUM ON STRUCTURE/ PROPERTY RELATIONSHIPS: PHASE TRANSFORMATIONS AND ALLOY DESIGN Sponsored by The Mechanical Metallurgy, Structural Materials and Physical Metallurgy Committees oj TMS-AIME Tuesday, March 4, 1986 Mardi Gras D 2:00 p.m. Marriott Hotel Session Chairmen: Gareth Thomas, Lawrence Berkeley Laboratory, Materials and Molecular Research Division, National Center for Electron Microscopy, University of California, Berkeley, California 94720; Morris Cohen, Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
THICKENING KINETICS OF GRAIN BOUNDARY ALLOTRIOMORPHS IN Fe-C-2 W/O Mo ALLOYS AND THE THREE DEFINITIONS OF BAINITE: P. G. Bos-
well, Battelle Geneva Research Center, Geneva, Switzerland; K. R. Kinsman, Intel Corp., Santa Clara, CA 95051; G. J. Shiflet, University of Virginia, Charlottesville, VA 22901; and H. 1. Aaronson, Carnegie-Mellon Univ., Pittsburgh, PA 15213 Investigation of four Fe-C-2 W/O Mo alloys containing 0.055% to 0.25 W/O C, mainly at temperatures between the upper nose and the bay, has disclosed striking morphological and kinetic anomalies in the proeutectoid ferrite/bainite reaction. Widmanstatten morphologies are largely suppressed in favor of grain boundary allotriomorphs containing interphase or fibrous carbides. A little below the bay, the Widmanstatten morphologies begin to reappear, but in highly degenerate form. Near the bay, the thickening kinetics of allotriomorphs pass through a minimum. Both anomalies are ascribed to the solute drag-like effect of Mo upon the migration kinetics of disordered areas of austenite:ferrite boundaries. Present results strongly support the view that the generalized microstructural, overall reaction kinetics and surface relief definitions of bainite emphasize different groups of diffusional phase transformations phenomena.
(3:40 p.m.) INFLUENCE OF ALLOYING ELEMENTS UPON THE Ws TEMPERATURE OF Fe-C-X
(2:00 p.m.) MARTENSlTIC TRANSFORMATIONS AS A DEFORMATION PROCESS: G. B. Olson and Morris Cohen, Massachusetts Institute of Technology, Cambridge, MA 02139 Constitutive relations for transformation plasticity have been derived from martensitic transformation kinetic theory. Statistical analysis of the nucleation-site potency distribution defines an effective transformation stress for multi axial loading conditions, and predicts the particle-size dependence of kinetic stability in dispersed-phase systems. Kinetic models then quantitatively relate the flow stress to strain, strain rate, temperature, and stress state. The stress-strain curve can exhibit upward curvature under the combined influence of the softening contribution of martensitic transformation as a deformation mechanism and the hardening contribution provided by the
ALLOYS: H. 1. Aaronson, Carnegie-Mellon Univ., Pittsburgh, PA 15213; P. G. Boswell, Battelle Geneva Research Center, Geneva, Switzerland; G. J. Shiflet, University of Virginia, Charlottesville, VA 22901; and K. R. Kinsman, Intel Corp., Santa Clara, CA 95051
The effects of (usually) 1 and of 3 A/a x upon the Widmanstattenstart (W s ) temperature in Fe-O.S A/a C-X alloys have been investigated with optical microscopy, where X was successively AI, Co, Cr, Cu, Mn, Mo, Ni and S1. In general, the Ws temperature is displaced in the same direction and by roughly the same amount as the paraequilibrium y/(o. + y) temperature. Complications in this simple picture appear primarily in Fe-C-Cr and Fe-C-Mo as a consequence of special effects upon morphology and kinetics associated with the bay region. The implication that the Ws temperature occurs when a critical level of driving force for growth becomes available is examined in terms of the Jones-Trivedi analysis of growth by the ledge mechanism.
68 TMS Annual Meeting
(4:05 p.m.) DESIGN OF LOW ALLOY STEELS FOR THICK WALL PRESSURE VESSELS. J. A. Todd. Department of Materials Science, University of Southern California, Los Angeles, CA 90089-0241. The steels required for second generation coal conversion vessels must be fabricated in section sizes up to 400 mm thick and must withstand chemically hostile environments containing elevated temperature and high pressure hydrogen. Compositional modifications of 2!t;Cr-lMo and 3Cr-lMo steels have been developed to provide improved hardenability, strength, creep strength, reduced temper embrittlernent susceptibility and resistance to hydrogen attack. Transmission electron microscopy studies have shown that Cr additions significantly accelerate the carbide tempering kinetics, producing Cr-rich carbides which reduce susceptibility to hydrogen attack. The microstructural features contributing to the improved properties will be discussed.
(4:30 p.m.) DESIGN OF STRONG, DUCTILE, LOW ALLOY STEELS, Gareth Thomas. Dept. of Mat. Sci. and Min. Eng., and the NCEM, LBL, University of California, Berkeley, CA 94720. This paper summarizes our alloy design programs at Berkeley which ilize the principles of composites to achieve superior mechanI properties (strength, toughness, wear, etc. ,) in medium bon low alloy steels (austenite-martensite) and cold form'lity (strength, ductility) in low carbon dual phase (ferritetensite) steels. Applications of these principles have been cessfully attained in commercial production of steels for agriculture and structural applications. work was supported by the Director, Office of Energy Reh, Office of Basic Energy Sciences, Materials Sciences sion of the U.S. Department of Energy, under Contract DE-AC03-76SF00098.
PERIMENT AL METHODS FOR MICROGRA VITY TERIALS SCIENCE RESEARCH IV Sponsored by the Thermodynamic Data Committee, Materials Science Division, American Society jor Metals , March 4, 1986 Mardi Gras C 2:00 p.m. Marriott Hotel Chairman: R. A. Schiffman, Midwest Research Institute, Kansas City, Missouri 64110 Session Chair: M. P. Siebel, NASA/Michoud Assembly Facility, P.O. Box 29300, New Orleans, LA 70189
ESA organised already parabolic flights dedicated mostly to fluid physics and related to the Dl program. It is the intention to continue this program and extend it to other materi a 1 sci ence experi ments. A short descri pt i on of the different investigations is given.
(2:50 p.m.) LCW-GRAVITY PROCESSING OF DIRECTIONALLY SOLIDIFIED IRON-CARBON
TYPE ALLOYS; D.M., Stefanescu' PoA. Curreri**, and M. Fiskeo* *Department of Metallurgical Engineering, College of Engineering, The University of Alabama, P.O.Box G, University, Alabama 35486. * *NASA/MSFC, Alabama., A Bridger.lan-type directional solidification furnace was used to solidify Fe-C, Fe-C-Si, Fe-C-Si-P, Fe-C-Si-Ce and Fe-C-V samples during aircraft lowgravity maneuvers. Controlled solidification \1aS continued through a nulltler of aircraft parabolas, resulting in the solidification of the sample over alternate high-gravity (1 to 1.7 g) - low-gravity (10- 2 g) fields. It was found out that the austenite-cementite eutectic interlamellar spacing in Fe-C alloys decreases, the eutectic grain size in Fe-C-Si-P and Fe-C-Si-Ce alloys increases, and the secondary am spacing in Fe-C-Si and Fe-C-Si-P alloys increases, during solidification in low gravity. Also i t was observed that the low-gravity to high-gravity transition has a destabilizing influence on the solid-liquid interface. Experiments with Fe-C-Si-Ce alloys exhibiting spheroidal graphite have show.j that bouyance driven phase segregation can be prevented by 1ow-gravi ty proces s1 ng. Proposed follow-up experiments on the shuttl e will be discussed.
(3:15 p.m.)
A TEM STUDY OF MICROGRAVITY CONTAINERLESS PROCESSED NIOBIUM BASED ALLOYS: N. D. Evans and Robert J. Bayuzick, Oept. of Mechanical. and Materials Engineering, Vanderbilt University, Nashville, TN and E. A. Kenik, Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN. The 100 meter drop tube at the Marshall Space Flight Center has provided a microgravity environment for containerless processing of niobium based alloys. The use of either an electron beam furnace or levitation furnace allowed liquid drops 75 to 400 mg in mass to undercool as much as 0.22 Tm prior to splatting on a copper block. Subsequent transmission electron microscopy with energy dispersive analysis by x-rays, and convergent beam electron diffraction was used to identify and characterize the resul ti ng mi eros tructures. In addi ti on to grain refi nernent and extensions in solid solubil ity when compared to corresponding equilibrium morphologies, metastable structures have been observed and are di scussed.
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CONTAINERLESS LOW GRAVITY PROCESSING OF HYPERMONOTECTlC GOLD-RHODIUM ALLOYS: *J .B. Andrews and **M.B. Robinson, *University of Alabama at Birmingham, Birmingham, AL 35294, **Space Science Laboratory, NASA Marshall Space Flight Center, Huntsville, AL 35812 Hypermonotectic gold-rhodium alloys have been solidified under container less , low gravity conditions through use of the Marshall Space Flight Center 100 Meter Drop Tube Facility. Alloys melted and solidified under one "g" conditions exhibited sedimentation of the more dense immiscible liquid phase. However, redistribution of the two immiscible phases occurred during low gravity, containerless processing. Microstructural analysis indicated the formation of dispersions of the immisci ble phases and a tendency for the gold rich minori ty liquid phase to wet the free surfaces of samples. Aligned microstructures were evident in several samples. *Work has be-en supported -by the NASA Microgravity Science and Applications Division.
CRITICAL POINT WETTING DROP TOWER EXPERIMENT: William Kaukler, Dept. of Chemistry, University of Alabama, Huntsville, AL, 35699. The wetting of a near-critical interface on a container wall is being studied under a brief microgravity environment produced by the 100 meter MSFC Drop Tower. The interface between two flu1d phases will go through a first order wetting transition at some temperature below the critical temperature for the system. The experiment monitors the dynamic shape changes an interface or meniscus undergo while the vertical cylindrical ampoule containing the two fluid phases is taken from unit gravity to micrc>gravity. In one-g, the density differences between the two fluids causes distortion of the interface and of the contact angle between the interface and container wall. By changing the g-level alone, the Bond number for the interface can be varied by several orders of magnitude which causes a corresponding change in interface shape. Presented will be results of the two systems: carbon tetrabromide liquid-vapour and perfluoromethyl cyclohexane with isopropanol. The former is interest1ng because it is a single component system wi th a very dense liquid phase. The latter is the only system known where the first order wetting transition temperature has been independently measured.
(4:25 p.m.) (2:25 p.m.)
THE ROLE OF PARABOLIC FLIGHTS IN A MICROGRAVITY PROGRAM D. Frimout and A. Gonfalone, ESA/ESTEC, Noordwijk. The parabolic flight is a useful tool for simulating microgravity and for performi ng short duration experiments. Its real value is in the verification tests that can be conducted in preparation for sp.ace experiments in order to improve their quality and success rate. The low cost and the short turn-around time (less than four months between deci sion to perform the fl ights and the presentation of the first results) make such an aircraft attractive and efficient for the preparation of microgravity missions. The parabolic flights also allow to test new ideas with minimum effort at low cost.
BEHAVIOR OF A NON-WETTED MELT IN FREE FALL: W.R. Wilcox and R. Sen, Clarkson University, Potsdam, NY 13676. Metal and semiconductor ingots solidified in space have frequently had a smaller diameter than the containing silica ampoule. This has been attributed to non-wetting of the ampoule wall by the melt, causing the melt to pull away. This concept was tested by experiments in the KC135 aircraft during low g parabolic maneuvers. These experiments and theory showed that the liquid behavior is highly dependent on its contact angle. In cylindrical ampoules, separated columns of liquid and large gas bubbles on the wall were observed. In ampoules with a triangular cross section, the liquid pulled away from the corners. Beyond a critical contact angle it should touch the walls only along lines. For the melt to pull away completely, it must be repelled by the walls.
TMS Annual Meeting 69 (4,50 p.m.) TEMPERATURE DEPENDENCE OF SOLUTION-CONTAINER INTERFACIAL FREE ENERGIES OF CONJUGATE PHASES IN A MISCIBILITY-GAP TYPE SYSTEM *Kijoon Chang and **Donald O. Frazier, *Department of Chemistry, Alabama A&M University, Normal, AL, **NASA/Marshall Space Flight Center, Huntsville, AL
Observation of solidification processes in microgravity indicates ;hat outside of sedimentation, preferential wetting
and thermal migration of second-phase droplets can separate the phases of a binary mixture cooling through a miscibility gap. The temperature dependence of the liquid l -contalner and the liquidZ-container interfacial free energy difference is calculable from film pressures following ellipsometric film thickness measurements on surface films adsorbed from the vapor phase. Application to Young ' s equation can yield the zero contact angle transition temperature inside the miscibility gap. These determinations should compliment direct contact angle measurements done in microgravity to relieve contact angle distortions imposed by the gravity field near the critical temperature.
EXPERIMENTAL TECHNIQUES IN HIGH TEMPERA TURE SCIENCE IV Sponsored by the ASMIMSD Thermodynamic Data Committee Tuesday, March 4,1986 Mardi Gras F-G Marriott Hotel 2:00 p.m. Chairman: R. A. Schiffman, Midwest Research Institute, Kansas City, Missouri 641 JO Session Chair: W. Siekhaus, Lawrence Livermore National Laboratory, Livermore, California 94550
Knudsen cell and heated. A dark spot inside the uniformly bright disc of the orifice appears suddenly at the formation of the first traces of liquid phase. This first appearance of dark spot gives the solidus temperature. The temperature at which several dark spots coalesce into a single spot will be the . liquidus. This technique was used in determining the high temperature diagrams of Ta-U, W-U, and Re-U. *Present Address Chemistry Department, Texas A&M University, College Station, Texas 77843.
(3 :15 p.m.) METALS COMPATIBILITY DURING THE CHLORINATION OF MOLTEN CaC1 ·CaO 2 SALTS: c. E. C. Rense, K. W. Fife, M. D. Ferran, Los Alamos National Laboratory, Division of Materials Science and Technology. Direct reduction of plutonium dioxide to plutonium metal uses calcium in a molten CaCl solvent, 2 llCaCl Pu0 + 2Cao ~ Puo + 2Cao.nCaC1 2 2 Due to the limited solubility of CaD in CaC1 , the solvent salts 2 are currently discarded after each reduction. Research into converting these salts back to 100% CaCl by reacting the molten salt 2 with either Hel or Cl gas is well unoerway. Because ceramic re2 action vessel breakage is high, a metal container to hold the mo'ten salt and a sparge tube to deliver the gas are needed for the process. Results of a test program to find a suitable metal or alloy are presented. Data include results for pure metals, nickel based alloys, iron based alloys, and rare earth alloys. Observed corrosion includes general attack, selective leaching and integranular attack. Finally test results of actual hardware made from candidate materials are presented and discussed.
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PHASE RELATIONS FOR REACTIONS OF HYDilOGEN WITH SODIUM OXIDE BETWEEN 500 and 900 0 C:* E. Velegis and L. Leibowitz,
(2:00 p.m.) ACTIVITY OF ARSENIC IN MOLTEN Cu-As SOLUTIONS: * R H' Lamoreaux, K. H. Lau, R.D. Brittain, and D.L. Hildenbrand, SRI International, Menlo Park, CA. 94025
Knudsen cell mass spectrometry and torsion-effusion vapor pressure measurements were used to determine AS partial pressures over 2 molten eu-As solutions at As contents ranging from 3.2 to 28 wt % and at temperatures from 1133 to 1570K. Arsenic activities and Giebs energies of mixing were derived using the liquid As standard state. The results are in reasonable agreement with previous studies on solutions containing more than 14 wt % As.
*
This work was supported by the National Science Foundation, Division of Chemical and Process Engineering.
(2:25 p.m.) MEASUREMENT OF THE SURFACE TENSIONS OF LIQUID OXIDE SOLUTIONS BY PADDAY'S CONE TECHNIQUE. D. R. Gaskell and M. Kidd, School of Materials Engineering, Purdue University, W. Lafayette, IN 47907. Padday's cone technique allows determination of the surface tension of a liqUid from measurement of the maximum force exerted on a cone during its immersion in, or withdrawal from, the liquid. As the technique does not require rupture of the meniscus, an equil i bri um measurement of obta i ned. The surface tens ions of 1 iquid iron oxides have been measured at l460°C from iron-saturation to XFe?o, = 0.205 using Pt-Rh cones, and the surface tensions of Fe-saturat~d iron silicate melts and Fe-saturated calcium ferrite melts have been measured at l4l0°C using iron cones. The results obtained for the latter two systems are in good agreement with values in the literature obtained using the hollow cylinder technique. The surface tensions of liquid iron oxide differ significantly from the literature values and it is shown that the latter are incorrect because of an error in the experimental procedures used.
(2:50 p.m.) HIGH TEMPERATURE PHASE DIAGRAMS OF Ta-U, W-U, AND Re-U BY SPOT TECHNIQUE. D. Das, S.R. Dharwadkar, and M.S. Chandrasekharaiah,* Water Chemistry Division, Bhabha Atomic Research Centre, Bombay 400085, India. The accuracy of determining solidus and liquidus of binaries in which one of the components is Ta J W, Re, or Mo could be improved greatly using the "spot method" of Ackerman and Rauh. In this method, one makes use of the sudden change in the emissivity and reflectivity of the sample at the first appearance of the liquid phase. The alloy sample contained in a cup is placed inside a
Argonne National Laboratory, Argonne, IL. The decomposition pressure method, commonly used for investigating the phase relations in binary gas-condensed phase equilibria, was applied to the Na-Na2 o-NaOR-NaH corner of ternary Na-o-H system by constraining the NalO atomic ratiO to a constant value of 2, thereby allowing study of the Nazo-a system. Measured amounts of hydrogen were reacted with NazO (sealed in a thin-walled nickel crucible) and the equilibri\D1l hydrogen pressure (P) was determined as a function of hydrogen concentration (Xu). Discontinuities encountered in the isothennal ~ vs. XH plots were used to delineate the phase boundaries. Data fitted to analytical equations permitted construction of a major portion of the phase diagram and yielded pertinent thermodynamic information. Applicability of the method to other similar systems is discussed. ~rk
performed under the auspices of the u.s. Dept. of Energy.
(4:25
D.m.) THE PHOTOELECTRON SPECTRA OF INORGANIC THALLIUM SALTS: G. K. Schweitzer, D. R. Loder, Jr., J. E. Bloor, and R. E. Sherrod. Department of Chemistry, University of Tennessee, Knoxville, TN. The high temperature vapor He(I) photoelectron spectra of thallium fluoride, chloride, bromide, iodide, nitrate, metaborate, and sulfate are presented. These spectra are interpreted with the assistance of a relativistic MSXa theoretical program. The results of the program indicate that reassignment of previously held identificat ions of the predominantly thallium 6s molecular orbital levels are called for. The influence of the relativistic effect is discussed in detail.
(4:50 D.m.) ACTINIDE ALLOY PREPARATION BY COREDUCTION:* S. A. Apgar III and J. G. Reavis, Los Alamos National Laboratory, Los Alamos, NM. Selected binary and ternary alloys of thorium, uranium, plutonium, and americium with each other and with zirconium, yttrium, molybdenum, and lanthanum were prepared by coreduction of their compounds. The method used was reduction by excess calcium in a magnesia crucible in an argon atmosphere contained in a closed steel pressure vessel, or "bomb." Heating was inductive, and an iodine booster was used to ignite the reaction. The alloy regulus produced was mechanically separated from the slag after cool ing. Coreduction of mixtures of fluorides produced higher alloy yields than reduction of mixtures of fluorides with oxides. The alloys were characterized by Chemical and microstructural analyses. *Work done in the Materials Science and Technology Division of the Los Alamos National Laboratory under the auspices of the Uni ted States Department of Energy.
70 TMS Annual Meeting
FRACTURE TOUGHNESS TMS-AIME General Abstract Session Tuesday, March 4,1986 Regent 2:00 p.m. Marriott Hotel Session Chairman: E. E. Underwood, School of Materials Engineering, Georgia Institute of Technology, Atlanta, GA 30332
(2:00 p.m.) Influence of Prestrain History on Fracture Toughness Properties of a 4340 steel, P. K. Liaw, Westinghouse R&D Center, Pittsburgh, PA 15235 and J. D. Landes, American Welding Institute, Knoxville, TN 37777 The effects of prestrain history on fracture toughness properties values and JR curves) of 4340 steel were investigated. Monoprestrai ns decrease fracture toughness as compared to the in material. Increasing the monotonic prestrain level from to five percent decreases fracture toughness. Cycl ic preins, however, elevate fracture toughness. The effect of cycl ic train on fracture behavior is suggested to be related to ic softening characteristics of 4340 steel. It was found that teri a 1 strength rat i ona 1 i zes the i nfl uence of prestra in history on fracture toughness properties. Furthermore, dimple fracture was observed regardless of prestrain history.
variations in tortuosity could be qu;mctfied. This same technique allowed for detailed t!xamination c)f anomalous features within the shear lip of tensile s.pecimens. features which indicate the presence of a heating effect. The possibility of a chermoreechanical coupling at the head of movin~ crack tip is pursued frot! a theoretical standpoint. *Research sponsored by the Office of Naval Research.
(3:20 p.m.)
ANALYSIS OF FRACI1JRE SURFACE ~RPHOU:X;Y DURlOC FCP IN HIGH PURI1Y AL-4°fm BINARY AJ.l1)YS" Kingshuk Baner ji am Ervin E. Underwood, Fracture & Fatigue Research LalXlratory, Georgia Institute of Technology, Atlanta, Georgia 30332 QUANTITATIVE
An Al-4'l,cu alloy was therrromechanically treated to produce two different microstructures; large grain size with shearable precipitates am small grain size with non-shearable precipitates. Fatigue crack propagation experiments were comucted for various R-ratios in the near-threshold am Paris regimes at room temperature l.lf'rler laboratory environment conditions. Fracture surface roughness am crad~ deflections were characterized using previously developed tedmiques of quantitative fractography. Statistical hypothesis testing criteria based on fracture profile am bulk microstructural parameters were developed, which could detect microstlUcture sensitive crack growth at low stress intensities. Variation of the fracture profile parameters with stress intensity also provided a better, objective understaming of such microstructure related crack growth phenomena as closure and deflections .
"'This work was supported by NSF Grant No. U'1R-8204018
(3:40 p.m.) EFFECT OF Ti AND C ADDITIONS ON FRACTURE TOUGHNESS OF LASER WELDS OF Mo:* C. R. Hills, L. E. Pope, and J. L. Jellison, Sandia National Laboratories, Albuquerque, NM
87185
EFFECTS ON CLEAVAGE FRACTURE IN FULLY PEARLITIC
STEEL: J.J. Lewandowski, University of Cambridge, idge, U.K., and A.W. Thompson, Carnegie-Mellon University, ttsburgh, PA 15213.
pearlite interlamellar spacing and prior austenite grain size e independently varied to study microstructural control of vage fracture. The critical cleavage fracture stress, OF, obtained for each microstructure by testing bluntly-notched bars containing a size range of root radii and flank angles. in fully pearlitic microstructures is controlled by this interlamellar spacing only. Temperature independent values for OF were obtained on fine pearlite between 23°C and -125°C, while temperature dependent values were obtained on coarse pearlite. These results are discussed in terms of recent theories of cleavage fracture. and will be contrasted to the cleavage behavior of mild steels. Research sponsored by Fannie and John Hertz Foundation, the NSF, and a NATO Postdoctoral Fellowship.
(2:40 p.m.) EFFECT OF BORON ON THE LOW TEMPERATURE FRACTURE AND DEFORMATlON
OF B2 FeAl:* M. Crimp, K. Vedula and G. M. Michal, Department of Metallurgy and Materials Science, Case Western Reserve University, Cleveland, OR 44106 Addition of boron (0.2 at%) to polycrystalline, P/M processed FeAI (B2 crystal structure) has been found to change its room temperature fracture mode from intergranular to transgranular. This is bel ieved to be due to the effect of boron segregating to the grain boundaries resulting in better grain boundary adhesion. Boron is also found to modify the ductile to brittle transition temperature and improve the strength of the polycrystalline FeAl. Presence of stacking faults in the boron doped specimens indicates that the improvement in strength may be related to a change in the stacking fault energy. Effects of stoichiometry, grain size and level of boron addition (from 500 to 2000 ppm) are also being investigated and preliminary results will be presented.
The fracture toughness of laser welds in sintered Mo was consistently less than in vacuum arc remelted (VAR) Mo. Auger spectroscopy of in-situ fractured Mo welds determined that there is a correlation between higher 02 content and lower fracture toughness of sintered Mo. It appears that 02 segregating to the grain boundaries during welding promoted grain boundary embrittlement. Ti additions in the weld refined the grain structure and improved the fracture toughness. TEM studies show that C in the absence of Ti forms M02C within the grains and at grain boundaries in both sintered and VAR Mo. C further decreases the 02 content mi tigating the tendency for grain boundary segregation and embrittlement by 02' Ti in the weld getters 02 by forming Ti203 while precluding M02e formation. *This work was performed at Sandia National Laboratories and supported by the U. S. Department of Energy under contract
number DE-AC04-76DP00789.
(4:00 p.m.) DISLOCATION-FREE ZONE MODEL OF FRACTURE UNDER CYCLIC LOADING: S.-J. Chang and S. M. Ohr, Oak Ridge National Laboratory,* Oak Ri dge, TN 37831 We have shown previously that the presence of a dislocation-free zone (DFZ) between a crack tip and its plastiC zone is closely re 1 ated to the cond it i on for di sl ocat i on emi ss i on from the crack tip. In the absence of the DFZ, the crack tip is completely shielded from the applied stress and the local stress intensity factor becomes zero. In the present work, we have examined the effect of cyclic loading on the size of the DFZ and the distribut i on of di s 1ocat ions near the crack tip. It is shown that during reverse loading two distinct equilibrium distributions of dislocations are possible. The true distribution can be found, however, if we assume that the local stress intensity factor is equal to the critical stress intensity factor for dislocation emission. *Operated by Martin Marietta Energy Systems, Inc. under contract DE-AC05-840R21400 with the U. S. Department of Energy.
*
Research supported by NASA-Lewis Research Center, Cleveland, Ohio.
(4:20 p.m.) SEMI-AUTOMATED TOPOGRAPHIC MAPPING OF FRACTURE SllRFACES:*
(3:00 p.m.) HEATING EFFECTS DURIliG FRACTURE IN Ti-10V-2Fe-3Al:* J.D. BrY-'nt
and H.G.F. Wilsdorf. Dept. of Materials Science, Virginia. Charlottesville, VA 22901.
J. D. Bryant and H.G.F. Wilsdorf. Dept. of Materials Science University of Virginia, Charlottesville, VA 22901.
University of
Variation in mechanical properties of the beta-alpha titanium alloy Ti-lOV-2Fe-3Al were measured as a function (If_3'it.!rin ratei stJai? rates were varied from quasi-static (10 s ) up to 10 s - . Mechanic.:!1 testing consisted of tensile testing and K 1c testing. Distinct chan~es in reduction of area and fracture toughness were measured with variation in strain rate. Differences were also nnted in the fracture surfaces of specimens subjected to different strain rates; through the use of R n~wly developed semi-au coma ted sterco-phocogr.:J.mmetr'Y technique. these
The interpretation of three dimensional features from two dimensional scanning electron micrographs of fracture surfaces is important in that it assists in the identification of microstructures and the determination of their role in fracture. By equipping a standard Hilger-Watts stereo-photogrammetry viewer with transducers to moniter the X and Y translations of the stereo-pairs and the vertical translations of the light source used to read relative heights from the fractographs, voltages corresponding to sets of (X, Y ,Z) coordinates of features within the stereo-pairs can be obtained. The three transducer signals can then be recorded and interpreted using an analo~-digital converter and an ATT 6300 computer. Using this system, it is
TMS Annual Meeting 71 possible to generate calibrated topographic maps of any fracture surface, as well as carpet plots and ] ine profiles, by using commercially available software. *Research sponsored by the Office of Naval Research.
(4:40 p.m.) SHATTER TRANSITION BEHAVIOR OF HIGH STRENGTH STEEL PLATE: J.G.Cowie, M.Azrin, and E.B.Kula, Army Materials and Mechanics Research Center, 405 Arsena) Street, Watertown, MA 02172-2719.
In order to quantify the phenomenon of plate shatter under ballistic impact, the temperature dependence of the plate shatter behavior of high strength steels was investigated and correlated with selected mechanical properties. For a given projectile velocity and geometry, plate geometry, and crack starter, a temperature was found above which little or no cracking occurred and below which extensive cracking occurred. This temperature, termed the Plate Shatter Transition Temperature (PSTT), provides a relative measure of resistance to cracking under ballistic impact. AnalysiS of the ballistic and mechanical property tests revealed that PSTT varies inversely with both static and dynamic fracture toughness. Charpy impact energy and hardness displayed no direct correlation with the PSTT.
(S:OO p.m.) ON THE LOW TOUGHNESS OF VANADIUM-CONTAINING 3Cr-Mo PRESSURE VESSEL STEELS:* R. McClau~hry, E. R. Parker and R. O. Ritchie, Department of Materials cience and Mineral Engineering, University of California, Berkeley, CA 94720. Recent studies on a new class of 3Cr-Mo-Ni steels, developed to replace 2'4Cr-1Mo steels for thick-section pressure vessels in hydrogen service, have been shown to possess very high toughness levels (KIc cc 170 MPa/iii, Charpy transition temperature < -SOOC) fo 11 owi ng temper i ng at 650 to 700 0 C. When 0.1 to 0.2 wt pct vanadium is added for strength and creep resistance, however, these steels can show much lower toughness levels (KIc cc 70 MPalril, Charpy transition temperature> +50 0 C) after tempering at 650 0 C, a lthough the effect is not seen after tempering at 7000C. This effect is investigated in a 3Cr-1Mo-lNi-0.2V steel and related to the nature of the carbide precipitation. Deformation, fracture toughness and microstructural results are compared with those for conventional 2'4Cr-1Mo steels. *Sponsored by the Department of Energy, Advanced Research and Development Fossil Energy Materials Progra~
HIGH TEMPERATURE ALLOYS IV: Advances in High Temperature Materials Sponsored by the TMS High Temperature Alloys Committee Tuesday. March 4. 1986 Acadia 2:00 p.m. Marriott Hotel Session Chairmen: K. A. Green, Allison Gas Turbine Division, Indianapolis, IN 46206; D. L. Anton, United Technologies Research Center, East Hartford, CT 06108
(2:00 p.m.) ORIENTATION DEPENDENCE OF CYCLIC STRESS ASYMMETRY IN NiJAI-TYPE Ni3Ge SINGLE CRYSTALS: Han-ryong Pak, Leih-ming Hsiung,and Jinn P. Chu, New Mexico Tech, Socorro, NM 87801, Masaharu Kato, Tokyo lnst. of Tech., Yokohama 227, Japan, and Soji Nenno, Osaka Univ., Suita 565, Japan.
Recen tly the au thers (H. Po, L. H. and M. K.) carried ou t room- temperature cyclic deformation of Ni3Ge single crystals with one orientation and reported a cyclic stress asyrrunetry. In this study further tests were performed to obtain a better understanding of such stress asymmetry. Three orientations were selected and cyclic tests were made at room temperature under the control of total strains. The strain rate used was 1 x 10-3s -1 and the total strain amplitudes employed were between 5 x 10- 4 and 1.5 x 10- 3 • (245]-orientation showed that the cyclic stress amplitude is higher in compression than in tension,and that this stress asyrmnetry becomes more prominent as the strain amplitude becomes larger. [IIl}-orientation showed a similar stress asymmetrY,but at high strain amplitudes the stress difference becomes smaller. lI23]-orientation showed little stress asymmetry. These differences in stress asymmetry behavior will be explained.
(2:20 p.m.) EFFECT OF HEAT TREATMENT VARIABLES ON TIlE FATIGUE CRACK GROWTH BEHAVIOR OF Ti3Al + 10 Nb: M. A. Stucke, Materials Laboratory, AFWAL/MLLN, Wr1ght-Patterson AFB, OH 45433 and H. A. Lipsitt, Materials Laboratory, AFWAL/MLLM, Wright-Patterson AFB, OH 45433
The effect of different cooling rates from the B solution temperature on the subsequent fatigue crack growth behavior is considered. In addition, some data on the effect of variations in aging temperature on the fatigue crack growth rate are presented. Powder Ti3Al + 10 wt% Nb has been canned and extruded 0 at l204 c into bars. The samples were solutioned at l2040C for one hour and quenched into boiling water, molten salt or air cooled. The samples were machined into compact tension spec imens 0 and tested in an MTS machine at 650 C and a frequency of 1 Hz. The microstructures resulting from each heat treatment have been determined and correlated with the measured fatigue crack growth properties.
(2:40 p.m.) NEW HIGH ALUMINUM, LOW CHROMIUM CONTENT AUSTENITIC STAINLESS STEEL SUPERALLOYS. J. A. McCurty, R. Nekkant i, E. Rosa, and J. Moteff, Department of Materials Science and Metallurgical Engineering, University of Cincinnati, Cincinnati, OH 45221.
The B (Ni-Al) precipitate which forms in the new high aluminum (5%), low chromium (10-14%) content austenitic stainless steel superalloys show interesting stability for some high temperature. high strength alloy applications. The addition of titanium (1%) to these alloys modifies the B precipitate and improved high temperature properties are obtained. The distinctive feature of these alloys is that they form an aluminum oxide type film which is protective of the base metal in air to temperatures as high as 2400°F. Based on work conducted at the University of Cincinnati the properties of these new alloys are compared to those of conventional superalloys (A-28b). An attractive feature of these new alloys, which relates to their high aluminum content is their significantly lower densities as compared to conventional superalloys.
(3:00 p.m.) HIGH TEMPERATURE NON-METALLIC COMPOSITES AS TURBINE ENGINE MATERIALS* P. Nagy, G.S. Cruzen, Williams International Corporation, Walled Lake, Michigan
Carbon Carbon and ceramic composite materials are currently being evaluated as potential alternatives to cooled nickel base superalloys for use in advanced gas turbine engine applications. These materials have been shown to possess the attractive high temperature mechanical properties available in ceramic monoliths, while maintaining the degree of toughness and defect tolerance required in turbine engine design. The feasibility of these material systems for turbine engine applications is being determined via engine testing of hot section components. Carbon Carbon and ceramic composite components which have been designed, fabricated, and tested include turbine rotors, combustors and nozzles. The test results to date have been very promising, indicating a bright future for these material systems.
(3:20 p.m.) MICROSTRUCTURE AND MECHANICAL PROPERTIES OF SUPERALLOYS PRODUCED BY THE OSPREY PROCESSTM, R. K. Ch ien, Teledyne All vac, P.O. Box 5030, Monroe, N.C. 28111-0531.
The Osprey Process™ is a patented technology for the direct conversion of molten metal into shaped preforms by means of a gas atomizing and spray-depositing process. This approach eliminates the powder handling process which can cause severe contamination problems for the conventional powder metallurgy superalloys products. A program was initiated at Teledyne Allvac to evaluate the microstructure and mechanical properties of two superalloys (IN 718 and IN 625) produced by the Osprey Process™. Microstructure and mechanical property evaluations were performed in the as-sprayed condition and after various thermomechanical processing. The results will be discussed and compared to those of the cast and wrought IN 718 and IN 625 products produced by the conventional method.
(3:40 p.m.)
DEFORMATION BEHAVIOR OF A SINGLE-CRYSTALLINE NICKELBASE SUPERALLOY AT ELEVATED TEMPERATURES: Wal ter W. Milligan and Stephen D. Antolovich, Fracture and Fatigue Research Laboratory, School of Materials Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0100. Interrupted tensile tests were conducted on <001> oriented samples of PWA 1480, and the associated deformation microstructures were studied via transmission electron microscopy. Tests were conducted to plastic strain levels of 0.1% and 0.3%, at temperatures ranging from 22°C to l093 0 C, and strain rates
72 TMS Annual Meeting of O~5 and 50%/m!n. Several specimens which were tested to failure were also studied by TEM. Fundamental deformation mechanisms will be related to the ~bserved mechanical properties. Acknowledgements: The authors wish to thank Mr. Gus Swanson and Dr. David Duhl of P&W East Hartford for supplying This
the
research
sdmples was
that
were
sponsored
sulfate, and sulfuric acid concentration. Kinetics of dissolution of CuFeS , PbS, ZnS, and Fe , were also studied In acidic thiourea solullons. Finally, smal1 scale column leach tests were conducted on a low-grade sulfidic gold ore from new Mexico and the resul ts were compared wi th conven tional cyanide leaching tes ts.
tested to failure. by the NASA-Lewis
Research Center under Grant NAG 3-503, which monitored by Dr. R. C. Bill and Dr. R. A. Mackay.
is
(4:00 p.m. SURFACE INSTABILITY OF PLATINUM ALUMINIDE COATING AT ELEVATED TEMPERATURE CYCLIC EXPOSURE:' T. Manley, P. Deb and D. H. Boone, Naval Postgraduate School, Materials Science Group, Monterey,California 93943 The effect of surface structure of two structural groups of Platinum aluminide coatings were studied. Various heat treated Platinum aluminide coatings on IN-738 alloy were exposed to cyclic oxidation at 1100 0 C for various lengths of time. It was found cycling at elevated temperature enhances surface rumpling as ared to specimens which were not cycled, while Platinum-free did not show surface rumpling. Amount of rumpling is dependent on the coating structure and the relative tal distribution. Results of this study will be presented detail.
(3:00 p.m.)
ELECTROCHEMICAL STUDY OF THE HYPOCHLORITE ELECTROOXIDATIONPROCESS FOR LEACHING OF MOLYBDENITE: P. F. Jorge and G. P. Martins, Colorado School of Mines, Department of Metallurgical Engineering, Golden, Colorado, 80401. The electrooxidative leaching of molybdenite was investigated. Hypochlorite ion was electrolytically generated in a recirculating cell and used directly for leaching of a molybdenite pulp in an agitated reactor. The research consisted of the following components: (i) electrochemical kinetic characterization of a molybdenite electrode in contact with hypochlorite solution, by scanning voltametry; (ii) leaching kinetics of molybdenite in hypochlorite solution and correlation with the electrodekinetic behavior in (i); and (iii) testing of two hypochloriteelectrolyzer cell-conf igurations. Mathemat ical descriptions of the leaching-behavior and electrolyzer performance have also been developed.
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D.
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(4:00 p.m o
OF PLATINUM ON VARIOUS SUPERALLOYS SUBSTRATES:' . Ellis, P. Deb and D. H. Boone, Naval Postgraduate School, Materials Science Group, Monterey, California-93943 Surface topologies of Platinum on various superalloys substrates (Le., Rene-BO, IN-792, IN-792 + Hf, X-40 and IN-73B) were studied. Previous study has shown the processing va\iables which lead to the rough, convoluted surface structure of Platinum modified aluminide coatings. Therefore, a project was initiated to study the selective interaction of Platinum with various substrates element. It was found that as deposited surface structure of Platinum on various substrates exhibit similar surface structure. There is no difference in surface topologies of these specimens after post coating heat treatment for 1/2 hour at 870 0 e except for X-40 alloy. Results of this study will be presented and discussed in greater details.
3RZAK
)
PREDICTING THE RATE OF GALVANIC INTERACTIONS FROM ELECTROCHEMICAL POLARIZATION CURVES: Denny A. Jones, Department of Chemical & Metallurgical Engineering, Mackay School of Hines, University of Nevada Reno, Reno, NV 89557 The principles of galvanic interaction between electrically conductive dissimilar surfaces in an electrolyte will be described. Instrumentation for determining anodic and cathodic polarization curves in galvanic couples will be reviewed, and methods using curves to predict the ra te of galvanic reactions will be presented. Data from measurements on brass-steel couples will be used to illustrate the utility of the described methods. Additional galvanic reactions on mineral surfaces, having application to geochemistry and hydrometallurgy, will be discussed. Finally, composite polarization diagrams, which indicate the rate of galvanic reaction for alloys and minerals will be presented as a supplement to the usual galvanic series which gives only the tendency for galvanic In terae tion.
*Research sponsored by ONR.
(4:30 p.m.)
HYDROMETALLURGICAL REACTOR DESIGN & KINETICS IV Sponsored by TMS-AIME Hydrometallurgy, Physical Chemistry, and Electrolytic Processes, and SME-AIME Chemical Processing Committees Tuesday, March 4, 1986 La Galerie 6 2:30 p.m. Marriott Hotel Session Chairpersons: Patrick R. Taylor, Department of Metallurgical and Mining Engineering, College of Mines, University of Idaho, Moscow, Idaho, 83843; V. 1. Lakshmanan, Ontario Research Foundation, Mississauga, Ontario, UK IB3, Canada
(2:30 p.m.)
KINETICS OF LEACHING GOLD AND SILVER IN ACIDIC THIOUREA SOLUTIONS: J. C. Huyhua and 1. H. Gund!ler, Department of Metallurgical and Materials Engineering, New Mexico Institute of Mining and Technology, Socorro, NM 87801 Kinetics of leaching gold and silver in acidic thiourea solutions in the presence of Oxone monopersulfa te compound, (2KHS0 ' KHS0 · 4 5 The K SO ), was studie4 using the spinning disc technique. 2 A levels of concentrations in this study were 0.02-0.06 M thiourea, 0.005-0.015 M potassium monopersulfate (Oxone), and 0.01-0.09 M sulfuric acId. Temperature and rotation speed were maintained constant at 25 C and 600 rpm, respectively. The initial rate of gold and silver dissolution was described by a second-order polynomial equation as a function of thiourea, potassium monoper-
ELECTROCHEMICAL KINETIC BEHAVIORS OF MINERAL AND COAL PYRITES IN ACIDIC SOLUTION: K. Mishra, H. O. Ogunsola and K. Osseo-Asare, Department of Ma terlals Science and Engineering, The Pennsylvania State University, University Park, PA 16802 The electrochemical behavior of mineral pyrite has been studied in 1M HC10 solution in the potential range of -350 to 300 4 mY(SCE). Cyclic voltammograms reveal two reversible peaks in the anodic and cathodic sweeps Initially. These peaks are believed to be associated with surface processes. On extending the polarization for longer periods reoxldizable solution soluble species are generated resulting In an addi tlonal peak In the anodic and cathodic cycles. This new peak Is located in the same potential region as the reversible peaks thus resulting in a superimposed peak on the cyclic voltammogram. A similar peak Is also observed when experiments are conducted in H2S saturated solution. An attempt has been made to Identify the chemical origins of these peaks on the basis of the assocla ted charges and pertinent thermodynamic data. A comparison of the behavior of mineral pyrite with that of coal pyrite Indicates a significant influence of surface morphology and solid-phase impurt ties.
TMS Annual Meeting 73
INTERFACES IN COMPOSITES I: Mechanical 8ehavior Sponsored by the TMS-ASM COlllposite COllllllillee Tuesday, March 4,1986 Mardi Gras A-8 2:00 p.m. Marriott Hotel Session Chairman: Dr. Ashok K. Dhingra, E. I. DuPont de Nemours Company, Inc., Corporate Composites Venture, Wilmington, DE 19898
signs. In a preceding pdper, tbe authors focused on the geometric shape of fibers and ductile elastomeriL matrices. Based upon the model I...·here all the fibers assume a sinusoidal curvature in one spatial djrection, the flexible compos ite provides: (1) low Young's modulus in the range of low applied stress and high modulus in the range of high applied stress, (2) enhanced elongation, and (3) high energy associated with deformation. In this paper. the stress distribution at interface is determined and examined in relation to the tensile and shear strengths of the matrix and the interfacial bond strength. The analytical findings form the basis of modeling of the failure behavior.
(4:00 p.m.)
(2:00 p.m.)
INTRODUCTORY REMARKS: Dr. Ashok K. Dhinqra, E. I. Du Pont de Nemours Company, Inc., Corporate Composites Venture, Wilmington, DE 19898
(2: 15 p.m.) INTERFACE HYBRIDIZATION IN METAL MATRIX COMPOSITES: W. H. Hunt, and C. R. Cook, ALCOA Technical Center, Alcoa Center.-~ PA 15069 In many fiber-reinforced composite materials, the attainment of high strength and high fracture resistance are mutually exclusive due to the role of interface bond strength on the competing processes of fiber fracture and debonding/pullout. Materials with strong bonding exhibit good strength properties but poor fracture resistance, while relatively weakly bonded materials achieve improved fracture resistance at the expense of transverse strength. Earl ier studies in resin-based composite material s have demonstrated that, through selective coating of the fiber to produce controlled amounts of strongly and weakly bonded areas, increased strength-fracture energy combinations can be obtained. Such an approach has not been attempted in the metal matrix systems to date. In addition, the potential for alternative methods to Droduce the distribution in interface strengths such as interply as well as intraply hybridization, needs to be explored. Finally, consideration of the role of interface strength in discontinuous, al igned fiber reinforced composites in comparison to continuous fiber reinforced materials should be studied. The experiments reported here util ize a model system such as B/Al or SiC/AI in which prior fiber coating is employed to produce different fiber interfaces and different degrees of bonding. In addition, discontinuous al igned' fiber composite materials are generated to examine the combined influence of interface properties and fiber length. Interface strength and fracture testing are employed to characterize mechanical behavior.
Jr.,
PARTICCLATC WETTIN(; Mil PARTICLE:SOLID INTERFACE PHENOMENA IN CAST METAL ~IATJH:; CONPUSITES:* S-Y. Oh 7 ,(, J. A. Cornic+,;, and K. C. RU5sellT",(,cf. ~lass[lchusetts Institute of Technology, Cambrid~r-1A ·62~ [t Cump()site Naterials Center; (, Dept. of Materials Science 6. Eng.; § ~Jaterials Procl:'ssing Centerj ¢ Dept. of Nuclear Eng.]
Techniques to facilitA.tc- particle and fiber introduction into the melt include special surface preparation, coatings, melt additions, stirring, pressure infiltration, an<;l pre-heating the particles or fibers. Particles t)r fibers are often pushed by the solidifying interface and become concentrated in the last material to solidify. Theoretical studies Ilave approa.ched particle pushing froma number of kinetic or thermodynamic bases. Previous work on part icle wetting and particle pushing will be reviewed briefly, followed by a discussion of our new results in theoretical and experimental studies on solidification proceSSing of AI-alloy m[ltrix composites with 1\1203, SiC. and B4C particuL:ne dispersoids.
*
Research sponstlred by Office of Naval Research Strategic Defense Initiative undpr contract no. NOOOI4-84-K-049S.
(4:30 p.m.) FORMATION OF Mg 2 Si IN A PH-64AL ALLOY REINFORCED WITH SIC PARTICULATE: 11.,-~~honey(l), J. M. Papazian(2), and C. G. Rhodes(l).
Metal matrix composite (MHC) alloys sllch as PM-64Al reinforced with SiC offer significant increases in stiffness. Although more difticult to fabricate due to <1ssociated decreased ductility. aluminum matrix composites can be superplastically formed. However, this work shows that exposure to the high temperatures associated with SPF can rf's'llt in the formation of a phase iden'!fied as !'1g2Si. Formati(1n 'If thi.s phase depletes the matrix of r'lg which is later Iwcessary to Attain full prAcipitAtion hardf'>nnble .strength in PM··f1/,. Results will illllstrate 1) how free sil icon becomes a'.'.1ilable tn rCflct with Mg, 2) the pffpct of Mg2Si form;ltion nn subsPCltlent strength properties and 3) the chemislry and distribution of consitupnt particles when the second phase Mg2Si is present. 1) Member Technical Staff, Rockwell Intl. Science Center 2) Senior Staff Scientist, Grumman Aerospace Corp.
(2:45 p.m.) TOUGHNESS CHARACTERISTICS OF THREE-DIMENSIONALLY BRAIDED a-M203/
A£-Li COMPOSITES: A. P. Majidi, J.-M. Yang, T.-W. Chou, Center for Composite Materials, and Department of Mechanical and Aerospace Engineering, University of Delaware, Newark, DE 19716. The fiber/matrix interface in composites of fiber FP, an a-alumina fiber, in a matrix of aluminum-lithium, is found to be very strong. The strong interface, while providing good load transfer between the constituents and thus increasing the strength of the composite, has an adverse effect on the fracture toughness and impact resistance as demonstrated by the brittle behavior of unidirectional FP/A£-Li Composites under impact loading. One way to improve the toughness of such composites made with brittle fibers is, therefore, by weakening the interface bond. Another possible approach is by geometrical manipulation of fibers in the struc~r~ an example of which is provided by the three-dimensionally (3-D) braided fiber reinforced composites recently developed. In this paper, the toughness characteristics of unidirectional and 3-D braided FP/A£-Li Composites has been investigated under quasistatic and impact loading conditions, and the role of interface and the 3-D braided structure on the material behavior has been discussed.
(3:15 p.m.)
BREAK
(3:30 p.m.) MODELING OF THE INTERFACIAL BEHAVIOR OF FLEXIBLE COMPOSITES: Tsu-Wei Chou and Kiyohisa Takahashi, Center for Composite Materials and Department of MechaI\.ical and Aerospace Engineering, University of Delaware, Newark, DE 19716.
The term "flexible composites" is used here to categorize composites capable of sustaining deformations much larger than those in conventional unidirectional composites. Such performance of enhanced extensibility without sacrificing stiffness and strength could be achieved through innovative geometric and material de-
LEAD, ZINC & TIN I: Applications Technology; Challenges of the Changing Market Place Sponsored by the TMS Lead, Zinc & Tin Committee Tuesday, March 4,1986 La Galerie 2 2:30 p.m. Marriott Hotel Session Chairman: M. R. Toivanen, Noranda, Inc., 860 Cadieux Blvd., Valleyfield, Quebec J6T 4W2
(2 :00 p.m.)
WHAT IS THE CHALLENGE?: G. Jewett, Jewett and Associates, 39 Old Mill Road, Suite 2104, Toronto, Ontario, Canada MaX lG6
(2:30 p.m.) PRODUCT DEVELOPMENT-A VITAL LINK FROM THE MINE TO THE MARKETPLACE: GENE O. COWIE, P.E., PIONEER ENGINEERING AND MANUFACTURING COMPANY, WARREN, MICHIGAN
This paper divides the journey of zinc from the mine to the marketplace into four broad categories: extraction, alloy prodUction, metal working technology, and product development.
The paper focuses primarily on the product development process, as it relates to zinc alloy die casting, from the product engineer's viewpoint. The process is outlined and illustrated with a block flow diagram. The critical points are identified where the selection of materials may be influenced, and the problems related to the use of a new material are discussed. Finally, critical areas of the product development process are identified where additional technology will be useful or necessary in developing new markets for zinc alloy die castings.
74 TMS Annual Meeting (3:00 p.m.) rHE CHANGING DEMANDS ON PRIMARY BATTERIES AND THEIR IMPACT ON ZINC - A RAW MATERIAL: T. N. TELZROW. UNION CARBIDE CORP •• BP OIVISION P.O. Box 6056, Cleveland. OH 44101 The demand by device manufacturers for greater current carrYlng capac; lities began some twenty years ago and resulted in the development of the Alkal ine Manganese Dioxide battery system. Rate carry' ng capab; 1 i ty , 5 d 1reet 1y re I ated to surface areas: t~erefore. the Al ka I; ne system uti 1; zed powdered z; ne rather than rolled zinc stock.. M~nlaturizatl0n
of devices has put size constraints on batteries to the pOlnt that in some cases a single particle of zinc powder can be thicker than the height of a miniature battery.
Envi ronmenta 1 quest 1 ons have ra i sed the concern of us i n9 mercury as a gasslng lnhibitor in batteries. Reactlng to these concerns. the battery lndustry is investigatlng a host of gas inhib1ting "alloys" of Zinc to minimize or elimlnate the need for mercury. n any case the resu I t wi 11 be a demana on the z 1nc supp 1i ers for urer anO purer material and a better definition of gass1ng gents. both phys i ca 1 and chem1 ca 1 •
(3:30 p.m.) THE LEAD ACID BATTERY TEST: Past, Present, Facing the Challenge of the Future: P.J. Gurlusky, Johnson Controls, 5757 North Green Bay Avenue, P.O. Box 591. Milwaukee. Wisconsin 53201.
PHASE TRANSFORMATIONS IN COPPER ALLOYS I: A Review of the Phenomena Sponsored by the TMS Non-Ferrous Metals Committee and the TMS/ ASM-MSD Phase Transformations Committee Mardi Gras I-J Tuesday, March 4, 1986 Marriott Hotel 2:00p.m. Session Chairman: Professor David Laughlin, CarnegieMellon University, Department of Metallurgical Engineering and Materials Science, Pittsburgh, P A 15213
(3:00 p.m.) ON THE MASSIVE TRANSFORMATION IN COPPER BASED ALLOY SYSTEMS,
Mark R. Plichta, Department of Metallurgical Engineering, Michigan Technological University, Houghton, MI 49931. Many copper based alloy systems show the potential for undergoing a massive transformation. Indeed, some of the pioneering research on this type of phase transformation was performed on Cu-Zn and Cu-Ga alloys. This study focuses on identifying other Cu-based alloy systems which will likely exhibit one or more massive transformations. Prediction of these yet uninvestigated massive transformations is based primarily on two considerations: a) thermodynamics, i.e. whether an allotropic type transformation is present somewhere in the binary phase diagram, and b) kinetics, i.e. whether diffusional processes are rapid enough at a given transformation temperature to allow the potential massive product to form at reasonable rates and/or compete with other possible phase transformations. Experimental evidence as to the existence €If a few massive transformations in selected alloys will then be presented to test the reliability of the predicting power outlined above.
(3:30 p.m.) PRECIPITATION IN COPPER ALLOYS* L. E. Tanner and L. A. Jacobson, Physical Metallurgy Section, Lawrence Livermore Natlonal Laboratory, Livermore, CA 94550. Formation of compound or solution phases is used to increase the strength of both cast and wrought copper alloys for a variety of appl i cat ions, inc 1ud i ng e 1ectri ca 1 swi tch components, rocket combustion chambers and nozzles, high-strength electrical conductors, and injection molds for plastics. The alloy systems of greatest current interest, including Cu-Be, Cu-Co, Cu-Cr, and Cu-lr, are reviewed with respect to precipitation mechanisms (both with and without i ntermed i a te mechan i ca 1 deforma t ion) and ternary element effects. The most recently published microstructure characterization information is used as the basis for this review, and prospects for the development of other precipitation strengthened copper-base alloys with different elements are discussed. *WorY-performed -under the auspi ces of the U. S. Department of Energy by the Lawrence Livermore National Laboratory under contract number W-7405-ENG-48.
(4:00 p.m.)
(2:00p.m.) SPINODAL DECOMPOSITION IN COPPER ALLOYS: W. A. Soffa Department of Metallurgical and Materials Engineering, University of Pittsburgh, Pittsburgh, FA 15261
Theoretical developments by Hillert and Cahn in the late 1950's and early 1960' s identified spinodal decomposition as a spontaneous clustering process occurring at high supersaturations in thermodynamically unstable solutions quite distinct from a classical nucleat ion and growth process. The theory of spinodal decomposition provided a basis for explaining the "wave-like" clustering first observed in the Cu-Ni-Fe alloy in the early 1940's and later found in numerous metallic and non-metallic systems. In this paper the experimental work on copper-base "spinodal alloys" will be reviewed with an emphasis on results stemming from electron microscopy (TEM) , X-ray diffraction, and atom probe field-ion microscopy (APFIM). The evolution and characteristics of spinodal microstructures will be discussed as well as the possible synergistics of clustering and ordering during ccntinuous phase separation. Also, the influence of spinodal decomposit ion on mechanical propert ies will be addressed.
ORDERING TRANSFOR:1ATIONS IN COPPER ALLOYS*: D. E. Laughlin, Carnegie-Mellon University, Pittsburgh, PA 15213
Various modes of ordering as exemplified in selected Cu alloys will be discussed. First order and higher order order/disorder reactions will be compared. Ordering in combination with other reactions (e. g. spinodal decomposition) will be discussed \vith examples taken from the copper alloys. The effect of crystal symmetry on equilibrium phase diagrams will be discussed with examples from copper alloys diagrams presen ted.
*Supported in part by DMR-NSF Grant 8413115 and by a subsistanee Grant from SERC of the U. K. during a Sabbatical at Oxford University
(4:30 p.m.) DISCONTINUOUS PRECIPITATION REACTIONS IN COPPER ALLOYS: D. B. Williams, Department of Metallurgy and Materials Engineering, Lehigh University, Bethlehem, PA 18015
(2:30 p.m.) MARTENSITIC TRANSFORMATIONS IN COPPER ALLOYS*: University of Illinois, Urbana, IL 6180l.
C. M. Wayman,
Martensitic transformations in copper based alloys such as CuAl, Cu-Sn and Cu-ln have been known since the 1930's or before. Until recently these transformations have received little i nteres t other than the research carri ed out by the academi cs. However, the reversible thermoelastic behavior of these copperbased alloys gives rise to some interesting properties such as the shape memory effect, and today commercial copper-based shape memory alloys such as Cu-ln-Al and Cu-Al-Ni alloys are readily available and in use. These memory alloys have many other interesti ng properties, such as a "two-way" shape memory, superelasticity, rubberlike behavior, high damping capacity, and the ability to und~rgo reversible stress induced martensitic and martensite-to-martensite transformation. These interesting properties will be discussed in some detail. *PartiallY supported by NSF Grant 83-16981 through the Materials Research Laboratory at the University of Illinois, IBM Corporation and the International Copper Research Association.
The grain boundary discontinuous precipitation reaction is a In this recommon phase transformation in many copper alloys. action, heterogeneous precipitate nucleation occurs on a grain boundary, in conjunction with boundary migration. The preCipitate can be a metastable or stable phase. In those copper alloys which exhibit homogeneous metastable precipitation or spinodal decomposition, a primary method of coarsening of the matrix preCipitates is through this grain boundary discontinuous reac tion. The coarsening leads to rapid overaging and invariab ly results in a degradation of mechanical properties. Studies of the initiation, growth, and prevention of this generally undes irab Ie reac t ion have been made in many c opper alloys. A t tempts to suppress the reaction through a variety of approaches have generally been unsuccessful. This paper will review our current knowledge of the initiation and growth of grain boundi"Ary discontinuous reactions in copper alloys, comment on their effect on properties and consider possible methods of elimination.
TMS Annual Meeting 75
PHYSICAL CHEMISTRY II: HETEROGENEOUS KINETICS OF METALLURGICAL PROCESSES Sponsored by the TMS Physical Chemistry Committee and the ISS/ PTD Tuesday, March 4, 1986 Mardi Gras N 2:30 p.m. Marriott Hotel Session Chairmen: S. M. Howard, Department of Metallurgical Engineering, South Dakota School of Mines and Technology, Rapid City, SD 57701; B. 1. Sabacky, AMAX, Inc., 5950 McIntyre Street, Golden, CO 8040]
(2:30 p.m.l THE IGNITION OF CHALCOPYRITE PARTICLES UNDER SUSPENSION SMELTING CONUITIONS*: P. C. Chaubal and H. Y. Sohn, Department of Metallurgy and Metallurgical Engineering, University of Utah, Salt Lake City, Utah 84112-1183 The ignition of chalcopyrite particles under suspension smelting conditions has been analyzed by considering the intrinsic kinetics of oxidation and heat and mass transfer between the particle and its surroundings. Under suspension smelting conditions (Sh = Nu = 2), chalcopyrite particles ignite at around 850 K. The effects of various parameters such as oxygen concentration, particle size, and gas temperature have also been elucidated. Comparison between calculated results and experimental observations by Jorgensent indicates that SU is the important gaseous product that forms at the surface of the particles. *Supported by NSF under Grant No. CPE-8204280 tF. R. A. Jorgensen, Proc. Australas. Inst. Min. Metall .. v. 288, pp. 37-96, 1983
(2:55 p.m.) KINETICS OF THE REACTIONS BETWEEN S02(9), 02(9) AND SOLID COPPER OXIDES: D. Eppelsheimer, P. Bolsaitis and J. F. Elliott, Dept. of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 Submicron-sized particles of copper oxides are formed by oxidation of copper vapor with a gas phase containing low concentrations of oxygen. The kinetics of reactions of S02(9), 02(9), and mixtures of these gases with the parti cles have been studied at temperatures between 400 and lOODoe by thermogravimetric analysis, and the reacted particles have been examined with SEM and TEM/ STEM. Reactions to form adsorbed layers of the gas species, and the convers i on of the oxi des to copper 5 u)fate have been 5 tudi ed also.
(3:20 p.m.) MASS TRANSFER OF
OXYGE~
TO MOL TF.N LEAD
U.S. Conochie and D.G,C. Ro!J~F~SOI"!, Dp.lJ81'tnll;-'nt or :v/pt.111urgy and Materials Science, Imperial College. London. S.W 72BP The open-top bubblE' apparatus (described by Conochip and
co-workers in Trans. I.M.M. 9~., (1984). C45-58) wus used to study the kinetic of mass transfer of oxygen to a stirred bath of molten lead. initially maintained in an inert nitrogen atmospherp at 450°C. A f.ixed quantity of OXygP.!1 (typically 10 ml at STP) was jetted onto the lead surface and rapidly formed a film of solid PhO which then dissolved in the lead at a rate determined by 1 iquid phase mass transff>r. Oxygen potentinls in thf' g<1S and metal IJhases were monitored by gas reference zirconia oxygen probes of our (lw"Tl des i gn. Two probes werf> used in the 1ead to prov ide a check and the probes could also be tested by changing the gas referencf'. Results will bp. given on thp. mass transfer coefficient in the lead and mass transfer in the gas phase will also be discussed. The kinetics of growth and dissolution of the thin PbO layer were so rapid as not to be limiting under ~hp experimental conditions.
(3:45 p.m.) KINETIC STUDIES FOR THE REMOVAL OF SULFUR FROM LOW-BTU GASES USING REDUCED IRON ORE PELLETS: E.L. Joyce Jr., Inland Steel Company, East Chicago, IN 46312, Kun Li and w.o. Philbrook, Carnegie-Mellon University, Pittsburgh, PA 15213
Use of commercial iron ore pellets as a. sorbent for desulfuri0 zing a simulated low-Btu g,s was investigated at 700 to 900 e and I to 5 atmospheres. In addition to the kinetic data, optical microscopy, SEM, and diffusion studies were used to characterize the structure of samples. The sulfidation reaction was found to occur on iron and to be controlled by pore diffusion through the FeS product layer. The rate of sulfidation decays quickly in the first minutes due to the formation of this dense
FeS phase. The effective diffusivity was found to be far lower than in the reduced iron. The low diffusivity of this phase is likely the result of two factors: the chemical density differences between Fe and FeS and the sintering observed in the FeS layer. The model for sulfidation considers multicomponent and Knudsen diffusion as rate-controlling.
(4: 10 p.m.) CHLORINATION OF ALUMINA WITH CO-CI -He GAS MIXTURES; PHOTOLYTIC EFFECTS: M.K. Soleiman ana Y.K. Rao, Department of Materials Science and Engineering. University of Washington, Seattle, Washington In the chlorination of alumina grain with CO-CIZ-He gas mixtures. two interesting phenomena have been observed. The first relates to a break-down in the Arrhenius behavior of rate constant (for chlorination). This break was noted to occur in 0 the temperature 'range 670-850 C; within this range the rate constant declines with rising temperature. At higher temperature, the Arrhenius behavior 'returns but the plot, nevertheless. remains discontinuous. The second aspect deals with photolytic effects in chlorination. When the apparatus was completely shrouded, blocking off virtually all forms of electromagnetic radiation, the rate of chlorination declined very sharply; the rate constant for chlorination in virtual darkness was only a third to one-half of the value for chlorination under ordinary laboratory conditions. Detailed study was made of the photolytic effects and their variation with temperature.
(4:35 p.m.) THE EFFECT OF CHROMIUM ON THE HIGH TEMPERATUHt: H.1XED OXIDATlON OF IRON AND NICKEL BAS~D ALLOYS IN OXYGEN-CHLOJ{IN" H.1XTUHJ
The reaction. of pure iron and nickel in oxygen-chlorine mixtures in the temperature range 900 - 1200 K has been described in earlier presentations. Under some condition •• the rate. of the reactions can be catastrophic leading to very rapid consumption of the metals. The add.ition of chrom~um to allOYS generally reduces the rate of oxidation of the metal. but i t . effect on mixed corrosion in thiS environment is not known. The results of tests of iron-chromium and nickel-chromlUDl alloys in
environments which produced catastrophic oxidation of tne pure metals will be discu.sed.
PLASMAS FOR METALLURGICAL APPLICATIONS IV: Plasma Applications in Metals ProceSSing Sponsored by the TMS Physical Chemistry Committee Tuesday, March 4, 1986 La Galerie 1 2:30p.m. Marriott Hotel Session Chairmen: C. Twigge-Molecy, Hatch Associates, Ltd., 21 St. Clair Ave., E., Toronto, Ontario, M4T IL9, Canada; P. R. Taylor, Dept. of Metallurgical and Mining Engineering, Univ. of Idaho, Moscow, ID 83843
(2:30 p.m.) T. Kuwabara. T. Hiraoka, T. Oohashi, K. Takeda, K. Ichikawa, K. UmezaWa, Nippon Steel H irohata Works, Hirohata-Ku Himej i, Hyogo I Japan.
STUDY OF THE PROPERTIES OF A PLASMA ARC IN A VACUUM:
This paper covers a study of the plasma arc in terms of the characteristics of plasma behavior in a vacuum and its heating
efficiency. The conclusion is that the heating of mol ten steel wi th a plasma arc used as a heating source in vacuum degaSSing vessels is highly feasible. The authors carried out the experiment using a transfer-type direct current torch. Results showed that the plasma arc vol tage is hardly affected by the arc length, gas flow rate or arc current, while it is greatly suscepti b1e to the extent of the vacuum. It was proven that CO and N2 in a vacuum will make the potential inclination of the arc column larger than in an Ar environment. At less than 100 Torr, the radiation loss of arc column decreased. This paper covers the first step of the study and is limited to the electrical and thermal properties of the plasma arc.
76 TMS Annual Meeting (3:00 p.m.) PLASMA MELTING OF LARGE DIAMETER TITANIUM INGOTS: R. C. Eschenbach, Retech, Inc., P.O. Box 997, Ukiah, CA 95482, S. C. Stocks, Oregon Met. Corp., P.O. Box 580, Albany, OR 97321. Production data are presented for melting ingots up to 28 inches in diameter and up to 180 inches long using plasma melting into a withdrawal crucible, The feed 1s a mixture of sponge and alloy. Ingot composition matches the feed within experimental error with plasma melting, while conventional VAR technology requires special preparation of compacts, and alloy loss is common in electron beam mel ting. The process is as effecti ve for producing ingots containing high percentages of tin, aluminum and other low meiters as for Tl-6Al-4V aircraft alloy and commercially pure titanium. The feed size can range from all sponge and alloy to chunks as large as 12 inches.
(3:30 p.m.) TITANIUM ALLOY SCRAP RECLAMATION USING D.C. THERMAL PLASMA TECHNOLOGY: W. C. Roman, United Technologies Research Center, o Hartford, CT 06108, T. Wagner, Homogeneous Metals Inc., 13322. an era of growing awareness that conservation of materials be pursued in a cost effective manner, novel techniques are considered in the metals processing industry for converting la1loys into aerospace and industrial products. Advanced for recycling titanium alloy scrap have been investiat UTRC; included is the development of laboratory scale systems which can reclaim scrap material through a recycling process and thereby reduce limited availability and cost burdens of using only raw materials to produce the final product. This paper will describe details of the thermal plasma reactor and associated techniques that have demonstrated the ability to produce homogeneous, void-free 5-cm-dia. ingots of Ti-6AI-4V in an atmospheric pressure environment without loss of volatiles with no significant contamination introduction.
PLASMA TORCH IN LADLE METALLURGY: S. L. Camacho, Umsted Industr ial Park, Rt. 8, Box 11 4Z, Long-column plasma arc torches were employed wi th proven success in ladle metallurgy dur ing the past year. The plasma torches were installed on a ladle cover and used to (1) raise the molten steel temperature and/or (2) maintain the molten steel temperature in a 220-ton ladle. The raising or maintaining of the temperature of mol ten steel is required, for example, during sequence casting or when "aborts" are encountered during the continuous casting process. The hardware, and its use in this metallurgical process, is called Plasma Ladle Reheater (PLR). PLR "saved" ladle heats by plasma heating of the molten steel wi thout affecting the steel chemistry. PLR offers an alternative to "dumping" the ladle of mol ten metal into a heated mixer, where the metal chemistry will be altered and rendered out-ofspecification for continuous casting.
ment of very low oxygen pressures. Desulfurization experiments on a small (200 g metal) and medium size (25 kg metal) scale were carried out in a hermetically sealed furnace operated at slight pOSitive pressure. The results using a graphite and a MgO crucible showed that although sulfur levels as low as 0.008\ could be Obtained, the crucible had a significant effect on sulfur removal. This paper will describe the plasma furnace used, and results obtained on desulfurization. Some preliminary results using a CaD lining in the furnace will also be presented.
PROCESS MINERALOGY APPLICATIONS TO LIBERATION Sponsored by the TMS-SME Process Mineralogy Committee Tuesday, March 4, 1986 La Galerie 3 2:00 p.m. Marriott Hotel Session Chairmen:. William Petruk, CANMET, Department of Energy Mines, and Resources, 555 Booth Street, Ottawa, Ontario KIA 001; Frank F. Aplan, Mineral Processing Section, The Pennsylvania State University, University Park, PA 16802
(2:00 p.m.)
AN ASSESSMENT OF THE PROBLEM OF QUANTIFYING MINERAL LIBERATION; Peter T. Luckie, The Pennsylvania State University, 108 Steidle Building, University Park, PA 1&802 Like the weather, everyone talks about it, but no one seems to do anything about it. As we strive to improve our quantitative predictive capability for unit operations such as comminution, classification, concentration, etc., we seem to be forgetting the keystone that holds it all together - liberation. This paper assesses the current state-of-the-art for quantifying mineral liberation.
(2:30 p.m.)
LIBERATION AS A FUNCTION OF SIZE REDUCTION IN THE COAL-ASH-PYRITE SYSTEM: J. W. Perez, Freeport Minerals Company, P.O. Box 26 Belle Chasse, LA 70037, F. F. Aplan, Mineral Processing Section, The Pennsylvania State University, University Park, PA 16802 The effect of crushing on the liberation behavior in the coalash-pyrite system has been studied and a classification system developed to describe the different types of feed assemblages. Liberation behavior of the various species is well described in terms of fractional yields within a given size range. A simple negative exponential model was developed which fits the data well and can be used to simulate yields of coal and pyrite out of raw coal or middlings.
(3:00 p.m.)
(4:30 p.m.) A PLASMA FIRED CUPOLA FOR FOUNDRY APPLICATIONS: S. V. Dighe, C. B. Wolf, Westinghouse Electric Corp., Waste Technology Services Div., Plasma Center, Box 286, Madison, PA 15663, W. H. Provis, Modern Equipment Co., 336 S. Spring St., Port Washington, WI 5307l.i, A. D. Karp, Electric Power Res. Inst., P.O. Box 10412, Palo Alto, CA 94303. A test program on a 2.5 ton per hour plasma fired pilot scale cupola at the Westinghouse Plasma Test Center in Madison, PA, has indicated the abili ty to melt unbriquetted machining chips and other large surface area charge materials with potential operating and economiC benefits over conventional practice. The benefi ts include reduced coke requirements, lower wind rates, enhanced silicon recovery and improved productivity. The test facility and operating conditions are described and the experimental results presented and discussed. The project has shown that the potential exists for plasma technology to playa significant role in the foundry industry.
(5:00 p.m.) DEEP DESULFURIZATION OF IRON ALLOYS AND STEEL IN A PLASMA ARC
FURNACE USING SLAG! CONTAINING CaO, Al 2 0 3 , AND caC or CaF 2 : 2 S. Tochowicz, J. Jowsa, M. Rozpondek, Technical University of Czestochowa, 42-200 Czestochowa, Al.Zawadzkiego 19, Poland. Plasma arc furnaces can be used to advantage in steel refining, because the higher temperatures allow the use of slags of greater basicity, and closure of the furnace permits the attain-
THREE-DIMENSIONAL MODEL FOR LIBERATION PREDICTION: INFLUENCE OF ORE TEXTURE DESCRIPTION. G. Barbery and D. Leroux, Mining and Metallurgy Dept., Laval University, Quebec G1K 7P4, Canada. A model which predicts particle composition distributions resulting from the breakage of multiphase materials is presented. It is based on integral and stochastic geometry and it properly assesses three dimensional particle properties, as derived by Davy (1984). Among the model parameters, ore texture descriptors are important and difficult. A comparison is made of Poisson polyhedral texture and Boolean texture with Poisson polyhedra unit grains. Methods of texture quantification are outlined which include image analyzers as well as more conventional methods of physical separation.
(3:30 p.m.)
EFFECT OF GRAIN SIZE DISTRIBUTION AND GRAIN TYPE ON LINEAR AND AREAL GRADE DISTRIBUTIONS: C.L. Lin and J.D. Miller, Communication Center, 201-A ARB, University of Utah, Salt Lake City, Utah 94112, U.S.A. Linear and areal grade distributions from the results of image analysis have been used to estimate the volumetric grade distribution for liberation analysis. A computer program (PARGEN) has been developed to grow, irregularly shaped J multi phase particles which can be probed in order to establish the relationship between volumetric grade distribution and linear or areal grade dis tributions. Previous studies based on a fixed grain size, indicate that the volumetric grade and dispersion density of the particles have a significant effect on linear and areal grade distributions. In this paper, four kinds of grain size
distributions, uniform, exponential, nomal and ~<1eibull, are evaluated. Results suggest that grain size distributio!1 has only a modest effect on linear and areal grade distributions.
(4:00 p.m.)
METHODS OF DETERMINING AND EVALUATING THE LIBERATION CHARACTERISTICS OF MINERALS IN MILL PRODUCTS WITH A "MIAS" !MAGE ANALYSIS SYSTEM: William Petruk, CANMET, 555 Booth Street, Ottawa, OntariO, KiA OGl
A SEM-IPS image analyser has been interfaced with a microprobe and an energy dispersive X-ray analyser to create a microprobe image analysis system (MIAS) for measuring liberation characteristics of minerals in mill products. The system is deSigned to discriminate and identify every grain on the basis of its average atomic number and its composition. The discriminated and identified grains are then analysed to determine their sizes, to determine whether they are free, and to classify unliberated grains on the basis of area % of grain in host particle. An example is given of analyses and of evaluation of mill products from a bench test of a base metal ore.
(4:30 p.m.)
BARITE ORE POTENTIAL OF TAILINGS PONDS IN WASHINGTON COUNTY, SOUTHEASTERN MI SSOURI: Heyward M. Wharton, Mi ssouri Geological Survey. Box 250. Rolla. MO 65401. Four large tailings ponds were drilled and evaluated to determine their potential as sources of barite. Over 70 barite tailings ponds are present in the district; many are large and most of them abandoned. There may be as much as 2 million short tons of barite contained in the estimated 40 million tons of tailings in the area. Core samples were analyzed and tonnage-grade estimates prepared for each pond. The most favorable one contained about 1 mi llion tons grading 7 percent barite. or about 82.000 tons of the mi nera 1. Screen tests suggest about half the barite is in minus 400mesh sizes. Work by the U.S. Bureau of Mines on a Missouri waste pond sample yielded a marketable barite drilling-mud product after treatment by flotation. The Missouri Survey's study has attracted some attention, but no commercial recovery projects have been attempted to date.
RAPID SOLIDIFICATION TECHNOLOGY FOR TITANIUM ALLOYS I: Production and Processing Sponsored by the TMS Titanium Committee Tuesday, March 4, 1986 Mardi Gras H 2:00 p.m. Marriott Hotel Session Chairmen: F. H. Froes, Air Force Wright Aeronautical Laboratories, Materials Laboratory, AFW AL/MLLS, Wright-Patterson AFB, OH 45433; S. M. L. Sastry, McDonnell Douglas Research Laboratories, P.O. Box 516, Dept. 224, Building 110, St. Louis, MO 63166
TMS Annual Meeting 77 (2:30 p.m.) RAPID SOLIDIFICATION PROCESSING OF Ti ALLOY POWDERS: J.P. Lofvander, J.W. Sears, R.W. Wheeler, S.A. Court, H.L. Fraser, Dept. of Metallurgy, lkliv. of Illinois, 1304 W. Green, Urbana, IL 61801 Rapidly solidified powders have been produced either by laser spin atomization or by centrifugal atomization. Two alloys have been processed using these techniques, namely Ti-D.7Er and Ti0.9La (at .%) and the microstructures of the as-sol idified powders have been investigated. In the case of the Er containing alloy, supersaturated solid solutions based on Cl-Ti are produced. Heat-treatment of these powders at 7DO c C for one hou r results in the preCipitation of a refined dispersion of oxide particles. Annealing at higher temperatures (> gOODe) shows marked coarsening of the particles. In the case of powders of the La containing alloy, the microstructure in the as-solidified condition consists of a dispersion of refined La particles. These become La203 on heat-treatment at temperatures above 700°C by internal oxiaation • .Powders of both alloys have been consolidated using hot isostatic pressing, and the microstructures of these compacts have been studied.
(2:55 p.m.) SOLIDIFICATION AND STRUCTURE OF LASER MELTED TITANIUM ALLOYS: W. A. Baeslack III, The Ohio State University, Dept. of Welding Engineering, 190 West 19th Avenue, Columbus, OH 43210-11B2; s. Krishnamurthy, Metcut-Materials Research Group, P.O. Box 33511, Wright-Patterson AFB, OH 45433; and F. H. Froes, Air Force Wright Aeronautical Laboratories, Materials Laboratory, AFWAL/MLLS, Wright-Patterson AFB, OH 45433
Laser melting is an effective and relatively easy method for use as a rapid screening technique for evaluating rapidly quenched microstructures in experimental alloys. In this presentation, the solidification behavior and microstructures of laser melts in near-eutectoid titanium alloys and in the commercial alloys Ti-6Al-4V and Ti-15V-3Cr-3Al-3Sn are described and compared with rapidly quenched products produced at comparable cooling rates using various rapid quenching processes. Results indicate that the solidification substructure characteristics of the different products can be morphologically similar for comparable cooling rates.
(3:20 p.m.)
BREAK
(3:40 p.m.) NEW RAPIDLY
SOLIDIFIED TITANIUM ALLOYS PRODUCED BY MELT-SPINNING: R. Ray and P. Clemm, Marko Materials, Inc., 144 Rangeway Road, North Billerica, MA 01B62
Titanium alloys containing fine dispersion of titanium diboride have been prepared using a novel rapid solidification powder metal technology. Alloys such as Ii.Al, Ti-6Al-4V, and Ti-BA1IMo-IV are modified to contain 3-4% titanium diboride and then prepared as rapidly solidified powders by a melt-spinning pulverization technique. Powders are consolidated by hot extrusion. Room and elevated temperature tensile properties of titanium diboride dispersion containing alloys will be discussed. Microstructural characteristics of the alloys examined by TEM will be reported.
(2:00 P.m.) CURRENT STATUS AND CRITICAL ASSESSMENT OF RAPID SOLIDIFICATION S. M. L. Sastry, McDonnell PROCESSING OF TITANIUM ALLOYS*: Douglas Research Laboratories, P.O. Box 516, Dept. 224, Building 110, St. Louis, MO 63166 Rapid solidification processing (RSP) has opened a highly successful new route for the development of novel titanium alloys with beneficial microstructures and improved properties over conventional titanium alloys. The number of research groups active in the field has grown considerably 1n the last five years. RSP of titanium has transitioned from scientific curiosity to developmental studies aimed at specific applications of RSP titanium. Whereas progress has been rapid in the identification of novel alloy compositions and characterization of RSP microstructures. development of RSP powder production facilities has progressed rather slowly. The presentation will review the major developments in the field and areas for further study will be discussed.
(4:05 p.m.) CHARACTERISTICS OF POWDER PRODUCED BY THE ALTi-OlCY PROCESS: J. A. Megy. Albany Titanium, Inc., P.O. Box 887, Albany, OR 97321
Titanium powder is produced by sublimation of zinc from a zinc-titanium alloy precurser particle in the ALTi-OXY process. The pre curser particle is produced from a fully mol ten zinc-titanium alloy solution via one of several of the known particle forming techniques or by casting and comminuting the brittle zinc-titanium alloy. The process allows prealloying with other elements and rapid solidification of the zinctitanium precurser particles. Several examples of novel titanium products produced via this process will be presented.
(4:30 p.m.)
* This
review was prepared under the McDonnell Douglas Corporation Independent Research and Development program.
EXPLOSIVE COMPACTION OF TITANIUM AND TITANIUM ALLOY POWDERS: V. D. Linse, Battelle, 505 King Avenue, Columbus, OH 43201
Explosive compaction is being investigated as an approach to fabricate high density, high integrity structures from titanium and titanium alloy powders. This approach is particularly attractive for the powders made by rapid solidification since the explosive compaction process allows consolidation at temperatures well below that which would destroy the unique microstructures and properties imparted by the rapid solidification process. This presentation will cover the basic
78 TMS Annual Meeting mechanisms of the explosive compaction process and the criteria for achieving high density powder compacts and achieving high quality interparticle bonding. Scanning electron photomicrographs will be used to show the particulate aspects associated with the deformation and densification of titanium alloy powder structures and how it relates to the fracture behavior of the final compacts. The effects of using elevated temperatures for compacting titanium alloy powders will also be discussed.
(4:55 p.m.) HIP COMPACTION OF TITANIUM ALLOY POWDERS AT HIGH PRESSURE AND LOW TEMPERATURE (HPLT): D. Eylon, Metcut-Materials Research Group, P.O. Box 33511, Wright-Patterson AFB, OH 45433 and F. H. Froes, Air Force Wright Aeronautical Laboratories, Materials Laboratory, AFWAL/MlLS, Wright-Pattersor. AFB, OH 45433 This work is a part of an extensive study on the various methods for compacting titanium alloy powders and ribbons at the lowest possible temperature. The low temperature consolidation methods is desirable in compacting rapidly solidified titanium alloy products. Ti-6Al-4V and Ti-IOV-2Fe-3Al plasma rotating electrode process (PREP) powders were hot isostatically pressed (HIP'd) at 45ksi in the temperature range of IOOO-1200°F. The high pressure low temperature (HPLT) HIP I ing under certain conditions resulted in fully dense compacts with very fine alpha and beta microstructures. The origin of the fine structures J additional microstructural conditions obtained by subsequent aging treatments and related mechanical properties will be presented and discussed.
TECHNOLOGY IV: THE ANODE EFFECT Sponsored by the TMS Light Metals Committee , March 4, 1986 Ponchartrain Ballroom D Sheraton Hotel Chairman: Kerry Farmer, Potline Superintendent, of South Carolina, Goose Creek, SC 29445
(2:30 p.m.) STUDY OF ANODE EFFECTS IN CRYOLITE MELTS: P. Descl aux and J. P. R. Huni, Alcan International Limited, P. O. Box 1250, Jonquiere, Quebec, Canada, G7S 4K8. Laboratory studies of the current-voltage characteristics of anode effects were performed on a small scale conventional electrolytic cell. Measurements were obtained using cylindrical and conical anodes, cored in industrial blocks, and an electrolyte composition similar to that used in production units. Nominal temperature of the melt was around 1000°C. The conductivity (I/V) of this system on anode effect was obtained for different current~, vari ous anode immersi ons, di ameters and shapes. It was found that during the anode effect, the conductivity of the anodic surfaces is strongly dependent on the current density, and that the vertical face of the anode appears to be the only active surface, probably due to different gas-fi 1m hydrodynami cs. The 1aboratory results were The general behaviour of appl ied to industrial conditions. anode effects of production units confirm the interpretation of the 1aboratory results.
(2:55 p.m.) MODEL CELL STUDIES OF GAS INDUCED RESISTANCE IN HALL-HERaULT CELLS. A. Solheim and J. Thonstad, The Norwegian Institute of Technology, Norway. In aluminium cells the accumulation of gas underneath the anode causes an extra voltage drop. A model cell with aqueous mixtures of glycerol and l-propanol representing the bath and a porous plate through which air was passed representing the anode was used. Accumulated gas volume and ohmic resistance were measured as functions of gas inlet rate, interpolar distance, and angle of inclination. The gas volume as well as the resistance were strongly dependent on the size of the gas bubbles. With the proper selection of parameters realistic data were obtained, i.e. :;;::;:0.3 cm 3 /cm 2 gas filling and an increase in ohmic resistance corresponding to 300-400 mV extra voltage drop.
(3:20 p.m.) ANODE GAS BEHAVIOUR DURING ALUMINUM ELECTROLYSIS T. Utigard and J.M. Toguri, Department of Metallurgy and Materials Science, University of Toronto, Toronto, Ontario, Canada, MSS-1A4 The wetting behaviour of graphite anodes was studied during electrolysis by the means of a X-ray radiographic technique. The gas generation was observed at different current densities and electrolyte compositions. The experiments were carried out in graphite crucibles. During normal electrolysis, most of the current passed through the vertical sides of the anode as a large gas bubble covered the bottom of the anode. The surface tension of the electrolyte during electrolysis, as measured from the shape of this gas bubble, corresponded well with the literature data. The wetting of the graphite anode by the electrolyte depended strongly on the current polarity. During the anode effect, the anode was covered with a thin gas layer. When the electrode polarity was changed, instant wetting of the anode occurred.
REFRACTORY METALS AND ALLOYS IN NUCLEAR APPLICATIONS II: Fusion Energy Sponsored by the TMS Refractory Metals Committee Tuesday, March 4,1985 Iberville 2:00p.m. Marriott Hotel Session Chairman: L. B. Lundberg, Los Alamos Nat. Lab., P.O. Box 1663, Mail Stop J576, Los Alamos, NM 87545
(2: 00 p.m.) THE USE OF REFRACTORY METALS IN FUSION REACTORS.* F. W. Wiffen, Oak Ridge National Laboratory, Oak Ridge, TN 37831 Conceptual studies of fusion reactors have identified many of the design details and materials issues of these future electric power systems. These studies show a number of components where the use of refractory metal alloys offers potential performance advantages. If superconducting magnets are selected, they require alloys of Nb or V. For most components, the refractory alloys must compete with other candidate materials. The properties attractive to fusion include: superconductivi ty, high strength at elevated temperatures, compatibility with liquid metals, and high melting point. Limitations on the use of these alloys include an inadequate data base, difficult fabrication technologies, and sensitivity to interstitial impurities. The potential applications of refractory alloys in fusion reactors will be identified and the properties of the metals compared to the application requirements. ·Research sponsored by the Office of Fusion Energy, U.S. Department of Energy, under Contract No. DE-ACOS-840R21400 with the Martin Marietta Energy Systems, Inc.
(2:30 p.m.) EFFECT OF FAST NEUTRON IRRADIATION ON THE MICROSTRUCTURE AND MICROHARDNESS OF NIOBIUM-BASE ALLOYS: D. J. Michel and H. H. Smith, Naval Research Laboratory, Washington, DC 20375 The microstructure and microhardness of several niobium-base binary and ternary alloys, with molybdenum and zirconium alloying additions, were investigated ~ollawing fast neutron irradiation to a fluence of 17 dpa at 649 C. The results show that, although the neutron irradiation increased the density of the dislocation loops, the magnitude of the increase was least for the ternary alloy and that no evidence of void formation was observed. Even though a corresponding increase in the microhardness of the alloys was observed after irradiation, the magnitude of the microhardness increase was found to be a function of the alloy composition, with the smallest increast in the ternary alloys. These observations are in agreement with previous studies of the present alloys which demonstrated the effectiveness of the molybdenum and zirconium additions in suppressing void formation. The results are discussed from the viewpoints of the mechanisms likely to be responsible for the improved irradiation resistance and the possible implication of the results for reactor systems.
(3:00 p.m.) SWU.LlNG IN SELF-ION IRRADIATED NIOBIUM, R. Bajaj, B.O. Hall, G.R. Fenske and S.A. Shiels, Westinghouse Electric Corporation, Pittsburgh, PA 15236 and Argonne National Laboratory, Argonne, I L 60439
1his paper presents initial results of an investigation of swelling mechanisms in a model body centered cubic (bcc) metal; niobium. The objective of this work is to achieve an under-
standing of the elevated temperature swelling in bee rnetals-the prirne candidate alloys and composite matrix materials for space reactor applications. Niobium was irradiated with 5.3 MeV Nb,,· ions at temperatures ranging from 700'C to l200°C to a nominal dose of 50 dpa at a dose rate of 6 x 10- 3 dpa/s. Swell ing was observed over the entire range, with peak swelling of 7% at 900°C. The microstructural data were compared to the predictions of the theoretical model developed. A reasonable agreement was obtained between the experimental measurements of swelling and theoretical predictions by adjusting both the niobium-oxygen binding energy and the incubation dose for swelling to realistic values. This work was sponsored by the U.S. Air Force Office of Scientific Research. (3:30 p.rn.)
SOLID AND LIQUID MIXTURES II Sponsored by the TMS Solidification Committee Tuesday, March 4,1986 Bacchus 2:00 p.m. Marriott Hotel Session Chairman: R. J. Schaefer, Metallurgy Division, National Bureau of Standards, Gaithersburg, MD 20899
(2:00p.m.)
VOIO FORMATION AND SOLUTE SEGREGATION IN ION-IRRADIATEO
VANAIJIUM-BASE ALLOYS.: B. A. Loomis, J. Wallace and B. Kestel, Materials Science and Technology Division, Argonne National Laboratory, Argonne, Illinois &0439
The void-volume fraction in unalloyed V and V-base a] loys containing 2.5-15 a/o Ni, Fe, Cr, Mo, W, or Ti has been determined from observations of speclm'5§s transmissiog ++ electron microscopy following 4.0-MeV Ni or 3.4-HeV IV ion irradiation at 975 K to ,-"50 dpa. Also, the thermal- and irradiation-induced segregation of these substitutional-atom solutes to the specimen surface and to internal sinks in the irradiation-damaged layer have been determined by use of Auger Electron Spectroscopy and Energy Dispersive X-ray Spectroscopy techniques. The void-volume fraction and the segregation of solute atoms have been shown to be correlated by the solute diffusivity and the relative chemical affinity of the substitutional solutes for o.
i¥.
*Work supported by the U. S. Department of Energy.
(4:00 p.m.) ATOMIC DEFECTS AND DIFFUSION IN REFRACTORY METALS*: R.W. Siegel, J,N. Mundy, and L.C. Smedskjaer, Materials Science & TechnOlogy Division, Argonne National Laboratory, Argonne, Illinois 60439 Recent studies of the nature and properties of atomic defects in the Group V-B and VI-B refractory bcc metals and their relationship to atomic transport, using a variety of techniques, have resulted in a better understandi ng of the atomi c-defect mechanisms for diffusion in refractory metals, but problems remain. Below about half the melting temperature, self- and solutediffusion appear to be controlled by atomic exchange with monovacancies; at higher temperatures, diffusion is strongly enhanced above that normally associated with monovacancies. This enhancement, which is much stronger than that found in fcc rneta1 s, is apparently not due to divacancy formation, but might resu1 t from the presence of small equi 1 i bri um concentrati ons of highly-mobile self-interstitia1s. The present status of our understanding of the atornic-defect mechanisms for diffusion in the refractory rneta 1 s will be revi ewed, and ramifi cat ions with respect to their use in reactor applications will be discussed. *This work was supported by the U.S. Department of Energy.
(4:30 p.m.) CONDITIONS FOR GROWTH/SHRIt-IKAGE OF INTERSTITIAL LOOPS IN BODY-
CENTERED-CUBIC METALS*: Pittsburgh, PA 15235.
TMS Annual Meeting 79
B. O. Hall, Westinghouse Rt.D Center, ----
Because several sinks with positive but differing biases for interstitials exist simultaneously in body-centered-cubic metals during irradiation or implantation, evolution of the dislocation microstructure is more complicated than in face-centered-cubic metals. The relative values of bias or preference factors for network dislocations, loops, and <100> loops determine loop growth/shrinkage rates and cavity nucleation and growth rates. A model, based on chemical-reaction-ra te theory, has been developed to evaluate loop growth/shrinkage rates as a function of initial network dislocation density, loop densities, and relative bias factors. Condi tions for growth of <100> loops and shrinkage of <111> loops have been defined, and rates have been calculated with niobium as a model material for a variety of irradiation conditions.
GRAIN BOUNDARY / LIQUID METAl WETTING: STUDIES OF GRAIN BOUNDARY ENERGY ~ Alcoa Technical Center, Pa 15069 and Roger D. DOherty, Drexel University, Philadelphia Pa 15069. Two early methods of studying the variation of grain boundary energy, o(gb), with misorientation have used; 1) Texture studies of rotating single crystal spheres sintered onto a Single crystal substrate and iil misorientation determinations at gb seen In stir cast (rheocast) alloys. As a development of the latter method fine grained Al-Mg-Si alloys were briefly heated above the solidus, Quenched and the two types of gb studied: those wetted by the liquid, o(gb»2o(sll, and those only partially wetted, o(gb)<2o(sll. Studies of the groove angle in the second case allowed relative gb energies to be estimated. From determination of the grain orientations by SACP the importance of special gb was estimated.
(2:30 p.m.) THERMAL PHENOMENA IN ADIABATIC MUSHY ZONES: Steve 1 P. Marsh and M. E. Glicksman, Materials Engineering Department, Rensselaer Polytechnic Institute, Troy, NY 12181. Diffusion-controlled reca1escence behavior is studied in solid1 i qui d mi xtures of pure materi a 1 s. A novel techni que has been developed that permits detailed in situ measurements of microstructural coarsening in mushy zoneSVTa precision thermometric techniques. The mean temperature of the solid-liquid mixture is related to the volume fraction of sol id present and to a characteristic length scale of the microstructure through an appropriate stati sti ca 1 average of the Gi bbs-Thomson equat i on. Theoret i ca 1 considerations indicate that the sub-cool ing below the bulk equil i bri um rne 1ti n9 poi nt caused by the presence of curved i nterfaces will decay as t- 1 / 3 . This behavior is experimentally verified for two model systems (succinonitrile [SCN] and ethylene carbonate [ETC]) which have markedly different solidification morphologies. The implications for predicting solidification structures in castings will be discussed. The authors gratefully acknow1ed~e the support provided by the National Science Foundation, Divlsion of Materials Research, under Research Grant DMR83-08052.
(3:00 p.m.) PERMEABILITY IN PARTIALLY SOLIDIFIED DENDRITIC STRUCTURES:* R. B. Inturi and D. R. Poirier, Department of Materials Science and Engineering, The University of Arizona, Tucson, AZ 85721. The influence of dendrite morphology and volume fraction liquid on the permeability for the flow of interdendritic liquid in directionally solidified slags is examined. Two types of flow, parallel to and normal to the prirnary dendrite anns, are considered. In addition to presenting quantitative measurements of the penneabil ity, interacti ons between the fl owi ng interdendritic 1 iquid and the dendrites are described *The work was sponsored by NSF Grant DMR-8205554.
(3:30 p.m.)
Bl'eak
(3: 45 p .rn.) "'Work sponsored in part by U. S. Air Force Office of Scientific Research under contract No. F49620-83-C-Ol20.
INFLUENCE OF THE PERMEABILITY OF SOLID-LIQUID MIXTURES ON THE FORMATION OF LOCAL CHANNELS: J. R. Sarazin and A. Hellawell, Depar.tment of Metallurgical Engineering, Michigan Technological University, Houghton, MI. During alloy solidification, interdendritic liquid in the mushy zone frequently· differs in density from the bulk liquid and thus provides a driving force for convection. Local perturbations at the dendritic growth front can release liquid from the mushy zone and give rise to macroscopic interdendritic channels. The mechanism of formation and the factors which affect such perturbations are complex, but one important variable is the permeability of the mushy zone to fluid flow, which depends upon the
80 TMS Annual Meeting scale of the dendritic array and the fraction solid. Channel formation in Pb-Sn alloys is being studied in the range 5 to 50 wt. % Sn, to examine the influence of permeability on the incidence of channels in a given configuration with a constant slow
cooling rate.
(4: 15 p.m.)
MICROSTRUCTURE OF RHEOCAST ALLOYS J.Allen Cheng Diran Apelian and Roger D. Doherty, Drexel University, Philadelphia The current model of the development of the non dendritic structure of rheocast (stircast) microstructure is that plastic deformation of soft metal dendrites leads to plastic bending of the dendrite arms. These recrystallize to give high angle, high energy grain boundaries that can be fully wetted by liquid giving dendrite break-up. In order to test this idea, the rheocast process was applied to hyper eutectic and eutectic AI-Fe and AI-Si where the intermetallic phase Al3Fe and the semi-metal Si show high resistance to plastic deformation. Evidence for brittle fracture of the facetted phases with some limited plastic deformation was obtained. In addition the possiblity of non-coupled eutectic freezing was confirmed; this may allow a new purification process
STIC APPROACHES TO FRACTURE I Mardi Gras K Marriott Hotel Chairmen: M. G. Stout, Los Alamos National , Los Alamos, NM 87545; J. E. Hack, Los Alamos ational Laboratory, Los Alamos, NM 87545
IN QUANTITATIVE FRACTOCRAPHY: Ervin E. Underwood
and Kingshuk Banerji, Fracture and Fatigue Research Laboratory, Georgia Institute of Technology, Atlanta Ga 30332-0102
Research on quantitative fractography has focused on procedures that quantify the geometry of the fracture surface. The procedure of choice is based on vertical sections through the fracture surface. The resulting profiles, as well as the underlying microstructure, are studied in metallographic mounts. The two principal methods for determining the surface area depend on randomly sampled profiles. One method is based on the angular distribution of linear elements along the profile. The other, simpler method involves a linear parametric equation that relates the profile and surface roughness parameters. The validity of these methods has been confirmed with i3 computer simulated fracture surface of known area. The fracture characteristics of 4340 steels and Al-4% Cu alloys are calculated for three cases: an assumed planar fracture surface (the SEM photomicrograph); an assumed random fracture surface; and the actual partially-oriented fracture surface. Calculated results differ by more than 100% for some features. This work has been supported by NSF grant No. DMR-8204018.
(2:25 p.m.) FRACTURE VIEWED AS A FRACTAL PROCESS: 410 E. 73rd St., NY., NY 10021
D. E. Passoja,
A fracture surface is formed microscopically, at the atomic level, by breaking of individual atomic bonds and macroscopically, at the microstructural level, by progression of the fracture through the microstructural heierarchy. The surface that forms is rough and irregular and is difficult to characterize by using standard Euclidian geometry. It is possible to characterize fracture surfaces by using fractal geometry conceived by B.B. Mandelbrot. Although fracture surfaces evolve in space-time the final fracture surface geometry is time invariant and phase information is lost that is crucial to understanding the progression of fracture. By monitoring fracture dynamically and relating physical measurm~nts to the fracture it is possible to gain helpful new insights into fracture statistics.
(2:50 p.m.) STATISTICAL ASPECTS OF CRACKING AND MICROCRACKING IN BRITTLE SOLIDS: A. G. Evans, Department of Engineering. University of California, Santa Barbara. CA 93106
Some brittle solids fail by the unstable growth of spatially isolated cracks. The probabilistic aspects of failure of these materials can be described by a combination of weakest link statistics and fracture mechanics. The basic probabilistic laws are briefly described. Other brittle solids fail by the accumulation of microcracks at grain boundaries. leading to the formation of a macrocrack and eventual catastrophic crack growth. The interaction between microcracks and their coalescence violate weakest link statistics. The aiternatjve probabilistic procedures needed to address these more complex systems are described. with emphasis on the role of the residual stresses and their distribution.
(3: 15 p.m.) WEIBULL STATISTICAL FRACTURE THEORY FOR THE FRACTURE OF CERAMICS: J. J. Petrovic, Group MST-6, Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545
The Weibull statistical theory of brittle fracture will be reviewed with regard to its application to the fracture of ceramics. At present, this theory is the one most widely applied for ceramic materials. The fundamental bases of this theory and the assumptions which it employs will be indicated. Predictions of the Weibull theory with regard to volume effects on the strength of brittle materials and effects of multiaxial stressing will be presented. These predictions will be compared to experimental multiaxial loading fracture data for alumina tested in tension-tension and tension-compression stress states.
(3:40 p.m.) WEAKEST LINK VERSUS DISCONTINUOUS PROCESS ZONE CONCEPTS OF BRITTLE FRACTURE: Tova Li vne, Shou-hui Chen, Chong-soo Lee, and William W. Gerberich, Department of Chemical Engineering. and Materials Science, University of Minnesota, Minneapolis, MN 55455
Consider the fracture of medium strength steels. Ductile rupture is discontinuous hole growth terminated by hole coalescence or void sheet instabilities. Cleavage from a blunt notch (e.g. a lower shelf Charpy V-notch tf'st) can be described by a w€8kest link initiating instability. The f'Jrmer represents a multiplicity of origins while the latter is a single origin. Which of these two processes best describes the ductile-brittle transition for sharp cracks? To answer this, statistical distributions of grains and fracture origins were identified in a 120 ).1m grain size steel having a yield strength of 245 MFa at room temperature and 650 MFa at 123 K. Compact tension specimens were equipped wi th piezoceramic transducers to evaluate microc leavage onset. Termination of the test at various stress intensity levels, KI, followed by fatigue cracking at 6K KI allowed isolation of multiple cleavage origins. The preliminary conclusion is that a discontinuous process zone can describe the stochastic events leading up to brittle fracture.
«
(4:05 p.m.) STOCHASTIC APPROACH TO THE MODELLING OF CLEAVAGE FRACTURE: Tsann Lin, A. G. Evans, and R. O. Ritchie, Lawrence Berkeley Laboratory, and Department of Materials Science and Mineral Engineering, University of California, Berkeley, CA
94720.
Weakest-link statistics have been applied to model the onset of transgranular cleavage fracture in single phase metallic microstructures containing a known distribution of particles which act as crack nuclei. Using linear and nonlinear elastic so 1ut ions for the stresses ahead of a sharp crack, the v ar i at i on in fracture toughness with temperature is predicted from the lower shelf into the ducti le/brittle transition range. Comparisons are made with fracture behavior ahead of a rounded notch, using slip-line solutions modified for power hardening, and serve to highlight the critical effect of local stress gradient on micro-mechanisms of fracture. Predictions are compared with experimental data on mi ld steel, using ferrite/carbide structures chosen to vary independently carbide size and grain size.
(4:30 p.m.) ROLE OF 3RD ORDER STATISTICS IN DISCRIMINATING AMONG MODELS OF FATIGUE CRACKS GROWTH IN METALS: F. Kozin, PolytechnIC Institute of New York, Route 110, Farmingdale, NY 11735 and J. L. Bogdanoff. Purdue, W. Lafayette, Indiana 47907 crack growth 15 lookt~d upon as an nondecrcaslng stochast1c process. The suHabl11ty of several well k.nown dlstrlbutlons for de5Crlblng the tlme for a crack to progress a specHled amount 1~ dlscussed relat1ve to the coefflclent of shrewdn"e5s. Based upon avaIlable data, 1t Is shown that ·'wedkest lInk" dIstrIbutIons that have appeared In the lHerature are not 5u\table. Fatlgue
~rrever'i'ble
TMS Annual Meeting 81 further, Il Is demonstrated that to the contrary "stranges 1 \n'Ku d'slr1but\ons are cons'stant wHh the dala. finally, Impllcat\ons for stochastIc models of growth models are d1scussed. fatigue crack
UNDERCOOLED ALLOY PHASES IV Sponsored by the TMS Alloy Phases Committee Tuesday, March 4,1986 Mardi Gras E 2:00p.m. Marriott Hotel Session Chairman: J. H. Perepezko, Dept. of Met. and Min. Engineering, Univ. of Wisconsin, Madison, WI 53706
(2:00 p.m.) INTERFACIAL SUPERCOOLING: S. D. Peteves and G. J. Abbaschian, Dept. of MaterIals SCIence and Engineering, University of Florida, Gainesville, FL 32611 Solidification mechanisms of supercooled alloys are commonly discussed based on the bulk supercooling. Although this quantity is usefull in describing characteristics of the nucleating phases and heat transfer conditions, only a portion of it at the solid1 iquid interface, "Interfacial supercool ing", is the most dominant factor in determining the solidification process, particularly the interfacial compositions, ' kinetics and preferred orientations. Results of recent experiments on the solidification of Ga and Ga-In alloys into supercooled melts involving direct measurement of the interface supercooling and rates will be discussed. The study covers interfacial supercoolings up to about 4.5 °C, corresponding to about 55°C bulk supercooling.
(2:20 p.m.) DENDRITIC SOLIDIFICATION IN A SUPERCOOLED PURE t1ELT - A REEXAMINATION OF THE FISHER DENDRITE: V. Laxmanan, Visiting Scientist, NASA Lewis Research Center, Cleveland, OH 44135. The "Fisher dendrite" is one of the simplest models proposed to describe dendritic growth in a supercooled pure melt. The solution obtained may be considered to approximate the behavior of the Ivantsov dendrite for moderately small Peclet numbers. It will be shown here that the tip stability parameter, a, obtained by Langer and Muller-Krumbhaar, also follows from a reinterpretation of the Fisher dendrite analysis, without' resorting to a perturbation analysis. The results here indicate that for growth velocities, R, smaller than the maximum permissible value, Rm, there are only two permissible values of the tip radius, rt. For R « R , a will become negative for the smaller of these two m radii. The dendrite grows with the only possible tip radius, the larger one, in this limiting condition. Experimental results with succinonitrile will be compared with this new approach.
(2:40 p.m.) A METASTABLE EUTECTIC REAC~ION EJ Al!-Sj\; ::.YSl E!'1 H.Gohchl and Paul H.SlnnC)ll
metal Sclt:nce and Technology
J
Kyoto Unlvprslty
Sakyo-ku, Kyoto 606 JAPi">.N
FOllr metastable phdses '",'err? ldentlfled by SOlldlfY1Y"iCJ i\u-Sn dlloys of Au-29, 31 and 1Sat%Sn samples; three by droplet undercoollng method dnd two by gun quenchlng method. One of these metastablE' phases melts by the met"astable ('ut"'ctlC reactlon wlth the stdble [ phase. A portlon of thr=; metastable phase diagram lnvolvlng the metastable phase 15 gIven.
fraction, scanning electron microscopy and optical microscopy were utilized to characterize the structures obtained. *Work has been supported by the NASA Microgravity Science and Applications Division.
(3:20 p.m.) SURFACE
TENSJO~
H£ASUREHENTS OF lINDERCOOLED LIQUID HETALS AND
ALLOYS: J. Schade, A. McLean and W.A. Miller, Department of Metallurgy and Materials Science, University of Toronto, Toronto, Ontario, Canada MSS lA4. The levitation technique has been used to measure the surface tens ions 0 f undercooled 1 iq uid me tal and alloy droplets. The natural frequency of droplet rotation is determined using a Fourier wave analyzer; surface tension is then calculated from Ray lei gh I S equa t ion. Studies have been carried out to date on pure Fe, Ni, Cr and Co ,.as wcll as on various metal-S1 alloys. It has been found that quite large undercoalings can be ob[ain~d with this technique i l l certain pure metals: liquid Fe has been undercooled by S3SoC (IIT/T m 0 0.30) and liquid Ni by 452°C (l'l.T/Tm ~ 0.26), considerably exceeding the value of 0.20 Tm which is often taken as the undercooling at which homogeneous nucleation occurs in pure metals. In all cases, the linear variation of surface tension with temperature which was observed in the superheated range was found to extrapolate back throughout the undercooled region.
(3:40 D.m.)
PREDICTION OF THE STATE OF ORDER IN AS-QUENCHED METALLIC GLASSES J. T. StanleY. J. R. HIIlalret*. and J. R. Cost**. Arizona State Unlv~rSlty. Tempe. AZ. The properties ot as-Quenched metallic glasses depend on chemical and topol091cal short-range order states and these depend on th. rat. of cooling from the liquid. Van Den Stukel and Radelaar have proposed a model which can'b~ us.d to calculate the as-Quenched states as a function of cool inc rate. However. their model do.s no adequately describe much ot the experimental data. In our op"rnlon there are two ma I n def I c r enc I es I n the I r mode I: (I) the spectrum a activation energies for chemical short-range ordering )s not ta)(en Into account: ( I I ) another mechanism In addrtlon to the annealing out of excess free volume IS needed to describe the observed atom! mob 11 I ty changes. We propose a mod If I ca t I on of the above mode I tha uses (;) a spectrum of activation energies obtaIned frame chemIcal short-range orderIng studies on well annealed metal 1 IC glasses and (rl) a vacancY mechanism for atomic mobilIty. We WIll comoare the predictIons ot the two models for available experimental data. Centre d~Etud.s Nuclearr.s de GrenOble. Grenoble France ** Los Alamos National LaboratorY, Los Alamos. NN.
*
(4:00 r.m.) METASTABLE ALLOY PHASES IN RAPIDLY QUENCHED TI ALLOYS FROM THE
MELT.* S. H. Whang, Department of Metallurgy and Materials Science, Polytechnic Institute of New York, 333 Jay street, Brooklyn, NY 11201.
Rapidly quenched Ti alloys from the melt undergo extensive undercooling before solidification. As a result. many metastable alloy phases are found in rapidly solidified binary and ternary alloy systems while many intermetallic compounds are suppressed as a result of rapid cooling. A systematic study on the occurrence of metastable phases has been made in binary and ternary alloy systems. Attention is given to metastable ..1-and B-phases, glassy phase, and u.: phase. In particular, the occurrence of w phase was investigated in terms of cooling rate and pre-strain during cooling. The formation of such metastable phases will be discussed along with equilibrium phase diagrams and analyzed using fundamental parameters.
*
Research is sponsored by the Office of Naval Research
(4:20 p.m.) (3:00 p.m.)
UNDERCOOLING EFFECTS IN GAS ATOMIZED POWDERS: I.E. Anderson and M.P. Kemppainen, Naval Research Laboratory, Code 6321, Washington, DC 20375-5000
CONTAINERLESS PROCESSING OF BULK Ni60Nb40 ALLOYS:
*M.B. Robinson, and **J. B. Andrews, *Space Science Laboratory, NASA Marshall Space Flight Center, Huntsville, AL 35812, **University of Alabama at Birmingham, Birmingham, AL 35294 Spherical samples of Ni60Nb40 of 300mg in mass have been containerlessly melted and solidified using the Marshall Space Flight Center "100 meter drop tube facility. Alloys were processed using several sc.rface treatments and drop tube atmospheres. Resulting structures were compared to arc melted samples prepared at one "g" under an argon atmosphere. Varied structures were obtained as a function of sample surface treatment and processing conditions which indicated a significant variation in the degree of undercooling. X-ray dif-
The solidification morphology of gas atomized powders has been found to be a strong function of powder particle size and not significantly affected by gas thermal conductivity. Microstructural analysis of sectioned particle size fractions of Ar atomized Cu-S.3 Al (wt.%) powders revealed a transition at 10-20 um in the predominant solidification mode from cellular in larger particles to partitionless in smaller. A microstructural comparison with He atomized powders of this alloy showed no significant difference in solidification morphology in equivalent particle sizes. A solidification reaction path for ultrafine particles of the Cu-S.3 Al and a Cu-6 Si alloy, also investigated, will be proposed involving metastable equilibrium conditions accessible in undercooled atomized particles. The
82 TMS Annual Meeting
enhanced undercool i ng potent i al of ul trafi ne atomi zed part i cl es will be presented in terms of the reduced probability of molten droplet interaction with potent sol idification catalysts in a highly dispersed melt. (4:40 p.m.) UNDERCOOLED PHASES IN ALUHINUM-IRON ALLOYS: C. M. Adam and D. J. Skinner, Metals and Ceramics Laboratory, Allied Corporation,
Morristown, NJ 07960. There have been numerous investigations of metastable alloy phases in aluminum-iron alloys. In 1955 Scheil and Masuda
investigated metastable microstructures in several hypereutect ic alloys by quenching into liquid sodium. Recent progress in rapid solidification technology has produced new phases
variously described as quasi-crystals, 0 phase, and icosahedral phases, and the undercoalings associated with the formation of this type of metastable phase can now be assessed with reasonable accuracy. This paper will discuss methods of assessing the undercoolings associated with various metastable phases in aluminum-iron alloys; the AI-AI6Fe metastable eutectic, AI-AIFe microeutectic (Zone A) and the icosahedral a phase.
(9: 10 a.m.) THE EFFECT OF VARYING NIOBIUM, ALUMINUM AND TITANIUM ON THE PHASE STABILITY OF GAMMA-DOUBLE PRIME IN INCONEL 718;* John P. Collier, Song H. Wong and John K. Tien, Center for Strategic Materials, H.K.S.M., Columbia University, New York, N.Y.
IN-7IS, a medium temperature application nickel-base superalloy strengthened by both a Ni3 (AI, X) gamma-prime and Ni) (Nb, X) garnmadouble prime phase, becomes brittle at high temperatures after prolonged service times. This brittleness is caused by the transformation of the coherent garmna-double prime phase to an incoherent and plate-like orthorhombic Ni 3 (Nb,X) delta phase. This study investigates the effect of varying the (AI+Ti)/Nb and TilAl ratios on the phase stability of the gamma-double prime phase at different niobium compositions. Time-temperature-transformation diagrams were produced for ten modified IN-7IB alloys through the use of selected area diffraction, scanning electron microscopy with quantitative microprobe EDS analysis and X-ray metallography. These results are compared with the commercial IN-7IS alloy and correlations between chemistry and transformation mechanisms are discussed.
*
This program is sponsored by a Gift Grant from The Niobium Products Co. and is also helped by The Wyman-Gordon Co. and The Special Metals CorpolZation.
(9:30 a.m.)
WEDNESDAY AM
TMS-AIME General Abstract Session March 5,1986 La Galerie 1 Marriott Hotel Chairman: J. A. Horton, Oak Ridge National , P.O. Box X, Bldg. 5500, Oak Ridge, TN 37831
I:Unt=~UllY,
CARBIDE PRECIPITATION IN RAPIDLY CONSOLIDATED MOLYBDENUM ALLOY POWDER PRODUCTS: D.R. Ervin, C. Persad, L.K. Rabenberg and D.L. Bourell, Center for ~IS&E, The University of Texas, Austin, TX 78712. In carbide dispersion hardened molybdenum alloys, finely dispersed carbides are effective in retarding recrystallization. Two types of TZM powders (Mo-O.S Ti- 0.08 Zr - 0.02 C) were consolidated using a high energy rate technique. The supplied powders were produced by the plasma rotating electrode process (PREP) and by the plasma melted rapidly solidified method (PMRS). Carbide precipitate size and distribution in the consolidated product have been compared with those in the powders. Carbide composition and morphology were studied using scanning electron microscopy, and analytical transmission electron microscopy. Size, shape, and distribution of the precipitates have been correlated with mechanical property measurements and with specific consolidation energy input. This research was supported by DARPA, under NADC contract N6 2269-85-C-0222.
(9:50 a.m.) (8:30 a.m.) HIGH RESOLUTION STUDIES ON THE MICROSTRUCTURE OF HIGH DAMPING MARTENSITIC Cu-Zn-Al SHAPE MEMORY ALLOYS: Jeff Perkins and Kenj i Adachi, Materials Science Group, Naval' Postgraduate School, Monterey, CA 93943. In many shape memory alloys, the martensitic microstructure is derived from a B2 or 003 ordered parent phase, and consists of 24 different martensite plate orientation variants. These are organized in six plate groups of four plate variants each. The movement of the interfaces between plates when a martensitic alloy is subjected to stress plays an important role in shape memory behavior, and also is believed to affect the high damping properties of the a.lloy. In this work, boundaries between plate variants in as-quenched and in deformed samples were studied at the lattice imaging level of observation. Combinations of variants within the same plate group, and between different plate groups, were considered. Out of the 276 possible paried combinations of the 24 variants, only 16 unique types of pairs are found, as determined from the phenomenological theory of martensite crystallography. The direct observations by TEM reveal that transitions between plate variants take on a variety of forms, depending on the crystallographic relationship of the pair. and that some particularly unique transition situations develop between plate variants when the microstructure is deformed.
(8:50 a.m.) VARIATION OF LATTICE PARAMETER MISFIT WITH PARTICLE SIZE IN FeNi-AI-Mo and Al-Zr-V ALLOYS: H A Calderon, M. S. ZedalisJ J. R. Weertman and M. E. Fine, Dept. of Mat. Sci. & Eng. and Mat. Res. Ctr., Northwestern University, Evanston J IL 60201
Lattice parameter disregistry 0 is shown to influence the coarsening kinetics of coherent precipitates. By lowering 6 through appropriate alloying, the rate of Ostwald ripening may be decreased. It is commonly accepted that 6 will remain constant throughout the coarsening process. Measurements of 6 in Fe-Ni-AlMo and AI-Zr-V alloys indicate that it depends on the aging time and therefore on the particle size. At relatively short times the magnitude of the misfit is observed to increase very rapidly. At long aging time)! ~ 6 changes more slowly and approximates to a stable value. In che alloy Fe-9. 7Al-3Ni-l.5Mo 6 varies from -0.08% after 12 h to 0.46% after 400 h at 70~C. The variation in 6 may be due to a variation in composition or formation of defects at or near the interface, both reducing the elastic energy of the system. Composition change is proposed to be the origin of the effect for small particle sizes; however, interface dislocations are definitely present at large particle sizes.
SPACE GROUP ANALYSES OF THIN PRECIPITATES BY DIFFERENT CBED PROCEDURES: * J.M. Howe, M. Sarikaya+ and R. Gronsky++, Dept. of Met. Eng. & Mat. Sci., Carnegie-Mellon University, Pittsburgh, PA 15213; +Dept. of Mat. Sci. and Eng., University of Washington, Seattle, WA 98195; ++National Center for Electron Microscopy, LBL, Berkeley, CA 94720. Convergent-beam electron diffraction (CBED) point and space group analyses were performed on thin 'I' precipitates, extracted from an AI-15 wlo Ag alloy aged for either 30 or 120 min. at 350 ·C. Although the space groups of precipitates in both samples were determined to be P63/mmc, it is shown that different results can be obtained, depending on the method of CBED analysis employed. Comparative analyses using a pure «-Ti standard demonstrate that the limited thickness of the plate-shaped precipitates is responsible for the variable results, suggesting a preferred method for point and space group determination of thin particles.
*This work was supported by the Division of Materials Sciences, Office of Basic Energy Sciences, U.S. Department of Energy under Contract No. DE-AC03-76SF00098.
(10: 10 a.m.) ATOMIC RESOLUTION MICROSCOPY STUDY OF ORDERED A93M9: J. Kul ik*, S. Takeda and D. de Fontaine, Department of Materials Science and Mineral Engineering, *Department of Physics, University of California, Berkeley, CA 94720
The long period superstructure phases of A93M9 were studied by transmission electron microscopy. Three compositions near stoichiometry have been investigated, each composition having been annealed at three different temperatures. Several new polytypes were observed and the (221221) phase, previously reported on the basis of diffraction evidence, has been imaged for the first time. An attempt is made to interpret general features of the phase diagram in terms of the currently topical ANNN I mode 1.
(10:30 a.m.) ONE-DIM LONG PERIOD SUPERSTRUCTURES IN CU3+xPd1-x OBSERVED BY HIGH RESOLUTION ELECTRON MICROSCOPY: S. Takeda, J. Ku 1 ik* and D. de Fontaine, Department of Materials Science and Mineral Engineering, *Department of Physics, UniverSity of California, Berkeley, CA 94720 Recent application of the ANNNI (Axial Next Nearest Neighbor Ising) model to long period superstructures in alloys has prompted a re-investigation of the Cu-rich Cu-Pd alloy system
using high resolution TEM. An extension of the simple ANNNI model comprising first (Jl > 0, "ferromagnetic") and third (J3 < 0, "ant iferromagnet i c") ax i a 1 pai r interact ions produces a phase diagram qualitatively similar to that of the Cu-Pd system, where the spi n arrangement of the mode 1 di agram trans I ates to the arrangement of Ll2 type unit cells separated by anti-phase boundaries in the real alloy system. The ratio J3iJi is expected to depend on the alloy composition. The model also predicts a qualitatively correct temperature dependence for the modulation wavelength, an experimental feature which has received only scant attention in previous investigations.
(10:50 a.m.) SPINODAL ORDERING BEYOND THE LIFSHITZ POINT IN Cu-Pd OBSERVED UNDER HIGH VOLTAGE ELECTRON MICROSCOPY: S. Takeda, J. Ku 1 ik*, S. Lacey* and D. de Fontaine, Department of Materials Science and Mi nera 1 Engi neeri ng, *Department of Physics, Uni versity of Ca 1 i forni a, Berke 1ey, CA 94720 The success i ve evo 1ut i on of the state of order from the completely disordered state of Cu-Pd alloys was observed at several temperatures. Complete disorder was initially produced by electron bombardment at -lBOoC. At 16 at.% Pd, both the initial SRO state and the final LRO state could be characterized by a special point (SP) concentration wave. At 18 at.% Pd, depending on the temperature, both SP ordering and the onedimensiona 1 Long Period Superstructures were produced from the same initial SRO state characterized by non-SP concentration wa ves. These resu lts can be exp 1ai ned if the sp i noda I orderi ng 1 ine for the SP concentration wave branches into two 1 ines at the Lifshitz point (corresponding to about 17 at.% Pd): one for non-SP (modulated) ordering waves, the other for SP ordering waves.
TMS Annual Meeting 83
ALTERNATE ALLOYING FOR ENVIRONMENTAL RESISTANCE V: Oxidation - Session II Sponsored by the TMSIMSD Corrosion and Environmental Effects Committee Wednesday, March 5, 1986 Mardi Gras L-M 8:30 a.m. Marriott Hotel Session Chairmen: G. R. Smolik, EG&G Idaho, Inc., Idaho National Engineering Laboratory, P.O. Box 1625, Idaho Falls, Idaho 83415; and S. K. Ban~rji, Ferroalloys Division, Foote Mineral Company, Exton, PA 19341
(8:30 a.m.) THE EFFECT OF VARIATIONS OF COBALT CONTENT ON THE CYCLIC OXIDATION RESISTANCE OF SELECTED NICKEL-BASE TURBINE ALLOYS: C. E. Barrett, NASA Lewi s Research Center, 21000 Brookpark ROnd, Cleveland,OH 44135. Cobalt level were systematically varied in the nickel-base turbine alloys U-700 (cast), PM/HIP-IJ-700, Mar-M-247, IN-738, Nimonic-1l5, U-720, SX-R-150 and Waspaloy. The levels ranged from O. w/o to the nominal cobalt content in each alloy. The alloys were tested in cyclic oxidation for one hour exposure cycles in static air at 1000, 1100 and l150°C for 500, 200 and 100 hours, respectively. An oxidation attack parampter, Ka derived from the specific weight change vs. time data was used to evaluatp and compare the oxidation behavior of the alloys. X-ray diffraction was also used to analyze the sample scales and spalls. In general the cyclic oxidation resistance decreased wi th i ncreas i ng temperature a nd with i ncreas i ng coba It content. The coba 1t effect is exp I a i ned in terms of whether an alloy tends to form Cr 2 0 3 /chromite spinel or A1 2 0 3 /aluminate spinel at various temperatures.
(11: 10 a.m.) A CRYSTALLOGRAPHIC STUDY OF THE PEARLITE REACTION: ~hompson. and P. R. Howell. Department of Materials Science and Engineering, The Pennsylvania State University. University Park, PA 16802. Although there are numerous investigat ions reported in the literature concerning the pearlite reaction, the present authors consider that certain conclusions are open to question due to the errors inherant in the use of spot patterns alone in selected area diffraction patterns. Hence, a new technique has been developed which employs low camera length convergent beam electron diffraction (LCL-CBED) patterns. This technique routinely yields an accuracy of better than lOin determining ferrite/cementite orient at ion relat ionships and in certain instances, the accuracy can be as good as 0.1°. In this paper, the LCL-CBED technique will be discussed. Results concerning orientation relationships between ferrite and cementite will be presented from a study on an Fe-1.5% Mn - 0.15% C steel. A more detailed analysis on the relationship between ferrite, cementite and both abutting austenite grains has been obtained using a Hadfields !-tn steel.
(11 :30 a.m.) STRUCTURE OF AI-Mn ICOSAHEDRAL PHASE AT HIGH SPATIAL RESOLUTION;
K. Hiraga and M. Hirabayashi, The Research Instl tute for Iron, Steel and Other Metals, Tohoku University, Sendai 980, Japan High resolution transmission electron microscopy has been done with the axial illumination to reveal the structure of icosahedral phase of rapidly solidified AI-Mn alloys. Attention is focused on disordering or faults regardlng the quaslperlodic dlstrlhution of structural units in the observed lmages. Taklng account of the disordering, the observed HREM images are interpretable well with a three-dimensional constructlon of the Penrose type structure proposed recently by T. Ogawa (J. Phys. Soc. Japan 54 (1985) No.9, in press). A hierarchic structure model conslsting of 1cosahedrons proposed by the present authors (Sci. Rept. RITU, A32 (1985) 309) supports the present results a::-: well. The structural d1Sordering in the icosahedral allcy phase 1S discussed in comparison with the ideal models.
(8:55 a.m.) THE OXIDATION/CORROSION BEHAVIOR OF LOW-CHROMIUM Fe-Cr-Ni ALLOYS CONTAINING ZIRCONIUM OR NIOBIUM: D. J. Baxter and K. Natesan, Argonne National Laboratory, Argonne, Illinois 60439. Chromium is a vital constituent in many alloys and, as a general rule, at least 20 wt % Cr is required for the formation of protective scales on Fe-Cr-Ni alloys at 1000°C. However, in view of the strategic nature of Cr, it is desirable that new alloys with lower Cr contents be developed in order that the overall demand for Cr can be reduced. To address this requirement, a new series of Fe, 10-12% Cr, 8-12% Ni alloys containing Zr or Nb has been designed. Zirconium or Nb concentrations of up to 6 wt % were used to compensate for the low Cr contents, with the aim of providing oxidation/corrosion resistance comparable to that of commercial alloys containing in excess of 20% Cr. Experimental results show that at a high POZ' 1% Zr or Nb is sufficient to promote protective oxidation behavior, whereas at a low PO ' more Z than 3% of the quaternary addition is required. In mixed-oxidant (OZ/5 2 ) environments, Zr and Nb reduce both scaling rates and internal penetration of aggressive elements from the exposure envi ronments.
(9:20 a.m.) THE OXIDATION RESISTANCE OF THE NEW HIGH ALUMINUM, LOW CHROMIUM CONTENT AUSTENITIC STAINLESS STEEL SUPERALLOYS. J. A. McGurty, R. Nekkanti and J. Moteff. The results of continuing research at the UniverSity of Cincinnati to define the oxidation resistance of the new high aluminum content-low chromium content austenitic stainless steel superalloys are presented. The aluminum oxide type protective film which distinctively forms on these alloys can provide useful oxidation resistance to at least 2200°F. The results of furnace oxidation testing of coupons and electrical resistance testing of wire to 2200°F for soak periods of over 3000 hours are reported. The data obtained are compared to those of conventional nickel (80 Ni-20 Cr) and iron base (Fe-25 Cr-5 AI) alloys. The results establish that optimum compositions of these new alloys have properties for service above 2000°F in air which are superior to commercially available alloys. The electrical resistance of these alloys are reported for temperatures to 2400°F.
(9:45 a.m.) OXIDATION OF FE-AL-C ALLOYS IN
THE TEMPERATURE RANGE 700-1100oC:
Ching-Haai Kao and Chi-Meen Wan, Institute of Material Science and Engineering National Tsing Hua University, Hsinchu, Taiwan R.O.C.
High temperature oxidation in air of Fe-XAl-O.6c alloys containing up to 10
wt%
Al was studied in the temperature range 700-
84 TMS Annual Meeting
noooc.
Effects of temperature and alloy composition on oxidation rate were determined by a thermogravimetry analysis (TGA). Optical metallography and electron probe microanalysis (EPMA) were used to examine the oxide scales tormed on alloy surfaces. At any given temperature the oxidation rate of Fe-Al-C alloys decreased with increasing aluminum content. Multi-layers conSisting of oxide were observed on the oxidized samples. The most inner layer was found to have Al203' whereas the most out layer was observed to be mainly iron oxide.
(10: 10 a.m.)
ALUMINA AND BAUXITE V Sponsored by TMS Light Metals Committee Wednesday, March 5,1986 Pontchartrain Ballroom A 8:30a.m. Sheraton Hotel Session Chairman: W. C. Sleppy, Aluminum Company of America, Alcoa Technical Center, Alcoa Center, PA 15069
(8:30 a.m.)
The Effect of HfO? Substitutions for Cr on the Cyclic Oxidation Behavior of Fe-25Cr-5A1 Alloys: Jose Luis Vazguez-Rodriguez, Dept. of Metallurgical Eng. The Un~versity of Texas at E1 Paso, E1 Paso, Tx 79968 USA
ASPEN MODELLING OF THE BAYER PROCESS: J. M. Langa, T. G. Russell, G. A. O'Neill, P. Gacka, V. B. Shah, J. L. Stephenson, Alcoa Laboratories, Alcoa Center, PA 15069 and J. G. Snyder, Alcoa Pt. Comfort Operations, Calhoun County, TX 77978-0101.
The effect of the substitution of HfO? for Cr on the cyclic oxidation of Fe-25Cr-5A1 alloyl'i from 1000'C to room temperature is studied. Oxidation of alloys with Hf0 amounts from 0.00 to 2.00 % in 0.25 % increments was 2performed in air for 15 hours with a cycle frequency of one hour. It was found that small additions of ODS improved the cyclic oxidation of these alloys by transformations of the morphology, thickness, and configuration of the alumina scale. Grain boundary diffusion of Hf-Fe-Cr rich intermeta1lics is observed. Doping of the scale with Hf as a result of the transformation of these intermetal1ics as they integrate into the scale is assumed. This affects its structure and retards the transport of ions and cations through the scale, improving the performance of the alloys by decreasing the growth stress formation at the scale.
The ASPEN si mul ator was used to mode I AI coa' s Pt. Comfort Bayer refinery. All areas of the refinery including the lakes and powerhouse were modelled. Each area model was designed to be run stand-alone or integrated with others in a full plant model. The refining plant models were designed to be user friendly, flexible, and accurate. User friendly models were made through Fortran interfaces that allow easy use by persons with no ASPEN or computer programmi ng knowl edge. FI exi bi I i ty was achi eyed by building flow sheet options in the model that are available in the plant. Accuracy was accompli shed through improved phys i ca I property corre I at ions and mode I verifi cat i on wi th plant data. Detail s on these features and examples of mode I app I i cat ions are di scussed.
(9:00 a.m.) ANALYSIS AND SIMULATION OF THE ALUMINA CALCINATION PROCESS IN A
(10:35 a.m.) THE EFFECT OF MOLYBDENUM ON CORROSION AND OXIDE FILM OF C
Alabama 36849 and James L. Chao, Magnetic Peripherals, Inc., Cant rol Data Corporation, Minneapolis, Minnesota
55435.
The behavior of Co-Cr and Co-Cr-Mo alloys in chloride solution has been investigated by electrochemical techniques. namely potentiodynamic, potentiostatic and open-circuit potential measurements. 1m. anodic palarization curve of Co-Cr in O.SM
NaCI (2 of pH) at 25 0 C shows a wide range of passive potential and eventually breakdown of oxide film by pitting at O.65V(SCE), Ie the Co-Cr-Mo does not indicate pitting. The rate of metal conversion into oxide for the alloys in passive state, 1n the range of potential found both in the anodic polarization curve in natural exposure to chloride solution has been studied Automatic Ellipsometry and Auger Election Spectroscopy to improvement of pitting resistance by an additon of
ROTARY KILN:A.Viola, R.Baratti, Istit. Chim. Applicata, Facolta lngegneria, l'.zza D'Armi Cagliari, Italy ;A.'leodosi, t.urallumina SpA Portoscuso (CA), Italy A dynamic mathematical model has been developed to obtain the te!!! perature profile of the gas, the solid and the wall in a rotary kiln, for the calcination of aluminium hydrate produced by Bayer process. The model, which incorporates detailed relationships of the heat transfer mechanisms both for radiation and convection, takes into account the dust recycle in the gas flow, the dams and the cascaders inside the kiln. The model has been used both to i,!! vestigate the influence of process variables on the ki In performance and to elucidate operating features of the process. The results of the model, which are in the form of axial temperature profiles in the gas, solids bed and wall, and axial concentration profiles in the gas and solids, are in good agreement with measurements made on a 800 Tid rotary kiln at Eurallumina plant.
Control Data Corporation under contract
(9:30 a.m.)
CONTINUOUS PRECIPITATION SIMULATION: J. V. Sang, Alcan International Limited, Kingston, Ontario, Canada K7L 4Z4.
CU-ZN AND CU-AU ALLOYS IN ACIDIC SOLUTIONS C.A. Handwerker National Bureau of StandArds, ial Science and Englnnrlng, ".tAllurgy DIVision, Building 223,B266 Gaithersburg, "aryllnd 20899
Dealloying, 'Dr selective corrosion i l I co •• on typi of corrosion in alloy SYltl . . . Ith cOlpon.ntt of differing nobility. Sy.tu. which are affected includo Cu-Zn, Co-Pt, F.-Ni-Cr, Cu-Au, Ind other alloy .ystol' Involving .triteglcilly Ilportont .. tal., S.loctive loaching i • • locllized ph.nollnon Ind thu., I. I plrticularly devastating type of attack. Th. surfac. of thl I.terial beco ... unstabl. and tho I.chanicil Ind chulcal propertil' of the alloy Ire adverilly aff.cted, often Itldlng to cOlponent failure or .hort.n.d IIrvlce life, Th • • ff.ctt of d .. lloylng on Cu-Zn and Cu-Au In acidic .nvironl.ntl MIre I nvesti gated. Th. oi cro.tructure of thl II lay. MIre .... I n.d bofore Ind after the dill laying procell. Th. co.po.1 tlon of the d .. lloyed Ireo .11 Invlltiglted II .11 the d.pth of III.ctlv. rllova!. Tho nchlnl .. of dl ffu.1 an of the IIhctl v.1 y I.achld IItal .11 considered and I lodel propolld.
Continuous precipitation circuits equipped with draft-tube agitated vessels are widely used in industry. However, simulation of such processes on the bench-scale has not yet been reported. Such simulation can be useful in optimizing existing circuits and in designing new circuits which will be somewhat more economical. It is well known that small scale experiments are not always a reliable guide to the performance of large scale units. Other conditions being equal, small scale crystall izers generally give finer products than large scale crysta II i zers. The object of thi s paper is to present a scheme using a chain of small, 6 litre, draft-tube crystallizers which can provide comparable yields and size distribution of the product at all stages of a continuous precipitation chain.
(10: 15 a.m.) THE STRUCTURE OF ALUMINATE LIqUORS, THE MODEL OF PRECIPITATION MECllANIZM
by
J.zlMaO,
ALUTERV-FKI, Budapest, Hungary
The structure, the atltoprecipi tation and the activated decompoai tion of supersaturated sodium al WIlinate 1 iquora were investigated. The structure of the liquor in the Na 0-A1 0;-H 20 2 2 systea and the proceaaea in same were interpretated in acc6rd with the practical experiences, by the measurement of the bulk properties /densi ty, viscoai ty, volumetric contraction, OB-ion activity, water activity, iaotbermic vaporization heat/, on the
TMS Annual Meeting 85 basis of the determination of the structure and the size of the speciea and of the larger structures in the liquor /by low angle X-ray analysio and light scattering measurement/ and the variation
in the composition of the liquor phase on the 8urface of seed crystals /determined by immersion heat and chemical analysis/.
(10;45 a.m.)
A HE\I PROCESS FOR REMOVAL OF ORGANIC IMPURITIES FROM BAYER LICUOR BY ,HE USE OF MANGANESE ORE; Dr. T. Tran, BHP, Austral fa
::0 Abs tract Ava il ab 1e
(11:15 a.m.) AUTOPRECIPITATION OF ALUMINA IN ,THE BAYER PROCESS, J. G, Lepet i t Aluminium Pechiney - Directipll des Essais et de la Recherche - . B.P. nO 54 - 13541 Gardanne Cedex A series of experiments was performed in order to determine the rates of precipitation of gibbsite and boehmite from Bayer liquors in contact with red muds I Different conditions of digestion - low or high pressure - a.nd autoprecipitation - during digestion, desilicatation. red mud washing - were tested with various bauxites. A general model based on thermodynamics and kinetics considerations was deduced from these experiments in order to estimate industrial autoprecipitation. This model takes into account the autoprecipitation conditions (temperature. Na 0 2 A1 0 , impurities concentrations) and red mud characteristics 2 3 (concentration, goethite content and yield at digestion). The model yields good aggreement with plant results ; by means of a study of autoprecipitation sensitiveness to variations in operating conditions, it is shown that this model allows to determine how t'o reduce the alumina losses.
(11:45 a.m.) The Role of Surfactant Adsorption in the Improved Dewatering of Alumina Trihydrate
D.J. Fox, A.G. Fane, C.J .D. Fell, R.G. Robins and M.S. Wainwright School of Chemical Engineering and Industrial Chemistry The University of New South Wales, POBox 1 Kensington New South Wales, Australia 2033.
(9;00 a.m.) MODELLING OF THE SEALING OF CATHODE BARS INTO CARBON BLOCKS: L. Michard, LRF Aluminium Pechiney, B.P. 114 -73300 Saint-Jeande-Maurienne A fini te element model has been developed, which calcula tes the thermal stresses induced by sealing a cathode bar into a carbon block, with cast iron. The modelling comprises two steps. First, a transient finite element programme computes the development of the temperatures over a cross-section of the block, the bar J and the cast iron (non-linear, two-dimensional model). Then a three-c!imensional finite element programme computes, at each time step, the thermal stresses and deformations. The agreement between the computed and measured development of both temperatures and deformations is excellent. The model has already enabled to forecast the effect on thermal stresses of parameters such as the preheating temperatures of bar and block, the temperature of the cast iron, the type of carbon, and the shape and size of the bar. It makes possible the optimization of these parameters in order to avoid sealing cracks.
(9:30 a.m.) USING THE THREE PARAMETER WEIBULL DISTRIBUTION FOR ALUMINUM REDUCTION CELL LIFE PREDICTION; C. A. Brown, Kaiser Aluminum and Chemical Corp., P.O. Box 6217, Spokane, WA 99207 Failure ages of aluminum reduction cells can be conveniently modeled using the three parameter Wei bull distribution. The mathematics are presented and complete reduction cell failure data are used to show that the distribution does provide a good fit. The use of a reasonab 1e est i ma te for the th i rd Wei bu 11 parameter, the 1ocat i on parameter, improves the fi tat the tails of the distribution. Using progressively censored failure data to determine the values for the Weibull parameters, a good prediction of t,he mean failure age of a group of cells can be obtained after a small fraction of the group has failed. A predicted number of failures from a group of cells during future time periods can be estimated based on their conditional survival probability. The calculations are read il y adaptab 1e to a dig ita 1 computer all owi ng rout i ne updating of predictions and easy analysis of special groups.
t
Additions of surfactant to either the feed slurry or wash water during filtration of alumina trihydrate assists product dewatering by increasing the solid-liquid contact angle in addition to reducing the filtrate surface tension. The adsorption kinetics and isotherms for anionic and cationic surfactants are presented for washed and unwashed alumina trihydrate from an Australian Bayer processing plant. In all cases significant adsorbed amounts were achieved rapidly. The cationic surfactant adsorbed most effectively and showed significant differences between washed and unwashed trihydrate. The anionic surfactant adsorbed less and was less sensitive to washing of the trihydrate. The differences are attributed to the presence of negatively charged humic species on the unwashed surface. Dewatering results are presented and interpreted on the basis of the surfactant adsorption studies.
(10;00 a.m.)
BREAK
(10:30 a.m.) CATHODE SERVICE LIFE ESTIMATION THROUGH MAXIMUM LIKELIHOOD TECHNIQUES, A C Weatherly, Coomonwealth Aluminum, 85 John Day Dam Road, Goldendale. WA 98620 Using Maximum L ikel ihood techniques, Weibul I functions are fitted to cathode life data. The probl em of mul t iple t ime-
censored (i. e., staggered start-up) data is addressed.
The
mathematical model is discussed and computational methods
for the determination of key service I ife statistics are defined. Two case studies demonstrate the use of statistical expectation and confidence bounds in estimating the average service life and future failure rate of groups of cathodes.
CARBON TECHNOLOGY V Sponsored by the TMS Light Metals Committee Wednesday, March 5,1986 Pontchartrain Ballroom C 8:30a.m. Sheraton Hotel Session Chairman: lean-Paul Huni, Alcan International Limited, P.O. Box 1250, lonquiere, Quebec, Canada G7S 4K8
(8;30 a.m.) A DESCRIPTION OF A NEW POTLINING EQUIPMENT; Kjell Nielsen, Dr. ing. Consultant. Hamangskogen 103, 1300 Sandvika, Norway. Ragnar A. Petlund. Lining of the cathode has been an unp1easent work. With handoperated tools, it is difficult to obtain a uniform compacting of all joints. Irregularity in the handling of paste mix may also influence the result. The new equipment consisting of a solid frame, easily mounted, fixed and adj usted to the pot, may be accomodated different pot sizes. A traveling bridge connected to the frame gives the tpal excellent access to any vital part of the cathode. The operation is noiseless because the normal rammers are replaced by an el-hydraulically powered roller. This tool may treat any mix, hot or cold, to optimal density controlled by potenslometer and secure a correct installed density. The operator, riding along with the tool, has excellent visibility and control. Performence data and reference to applications are given.
(11 :00 a.m.) ECONOMICS OF POTLINING DECISIONS; H. Dohner, Alean Smelters and Chemicals Ltd, Kitimat, B.C., V8C 2H2, Canada This paper discusses economic relationships between potlining cost, lining life, power consumption, metal production and metal contamination. It shows which costs to include for decisionmaking and gives a simple way of dealing with the time value of money under varying economic conditions. Special attention is given to the economics of pot shut-down criteria. Special situations are considered such as moving cathodes from a shut-down to an operating building, as well as decisions on restarting old pots in a shut-down building. It gives typical examples but also shows the method of calculation so as to adapt it to differing economic conditions.
(11 ·30 ".m.) ANODE DUSTING IN HALL-HEROULT CELLS.
M. Bruheim*; T. Foosnil!s**, K. Grjotheim*, and T. Naterstad**. *) Department of Chemistry. University of Oslo, 0315 Oslo 3, Norway. **) R&D Carbon, Ardal og Slll'ffidal Verk a.s, N-5875 Ardalstangen, Norway.
Operational irregularities originating from excessive dusting by selective anode oxidation have been experienced by most aluminium producers, particularly in Soderberg pots. The spatial distribution of carbon particles in the bath of aluminium reduction cells have been characteriZed by a combination of optical microscopy and gravimetric oxidation methods" Samples
86 TMS Annual Meeting covering the entire bath depth were obtained from prebaked and Soderberg cells by a specially designed sample collector, which was opened and closed while immersed in the melt. Quenched bath cores were sliced and prepared for microscopic gravimetric oxidation analysis to determine particle size distribution and total carbon content versus hath depth. The oxidation rate of carbon in the bath was studied in separate bench scale experiments. Resul ts are discussed in terms of practical operational impacts and applications.
CAST SHOP & RECYCLING V: Sponsored by the TMS Light Metals Committee Wednesday, March 5,1986 Grand Ballroom B Sheraton Hotel 8:30a.m.
8:30 a.m. DECOATING OF USED BEVERAGE CONTAINERS IN A THIN DOWN-FLOW BED; J. G. McCubbin, Alcan International Limited, P.O.Box 8400, Kingston, Ontario; J. Ayres, Alcan International Limited, P.O. Box 1250, Arvida Quebec; S. McCrae, Alcan Ingot and Recycling, Willow Run Road, Box 687, Greensboro, GA. Alcan began operating a prototype decoating plant on a production basis in mid 1981 in Oswego, N.Y. in late 1983 a second larger decoater went into operation in Greensboro, GA. The configuation of these units is oresented alonq with data on their operation.
See remainder of Cast Shop V abstracts In Addenda on page 137.
COPPER, NICKEL, COBALT & PRECIOUS METALS V: Sponsored by the TMS Copper-Nickel-Cobalt and Precious Metals Committee Wednesday, March 5,1986 La Galerie 5 8:30 a.m. Marriott Hotel Session Chairman:
SSIONING AND OPERATION OF ZCCM'S NEW COBALT PLANT, KITWE, A: P. J. Hansen, General Manager, A. Cross, Metallurgical ISuoerintendent, and G. K. Chibuye, Coba1 t Plant Superintendent, ivision ZCCM, Zambia Consolidated Copper Mines (ZCCM), , Kent, U.K. new cobalt plant at Kitwe in Zambia has been producing cobalt nce Oecember 1982. The plant was designed and constructed by ia Engineering Services Limited (ZES) of Ashford, Kent, nd, for the Nkama Division of Zambia Consolidated Copper Limited (ZCCM).· In this new plant copper/cobalt concentes are treated by a roast, leach, e1ectrowtn(RLE) process at sign rate of 130,000 tpa. The cobalt roaster offgases are ined with gases from a pyrite roaster and treated in a su1acid plant. In this paper a brief historical review is of cobalt production in Zambia up to the present situation.
effect of various parameters ,including time and temperature of leachim~, particle size, pulp density~ acid strength etc., are reported. An extraction of 75-80"'0 of Ni could be achieved from the serpentinic laterite, after 3h of leaching at 950C with 3N sulfuric acid, with an acid consumption of 1500 kg/t are. Under similar conditions, 80% Ni extraction could be achieved from the hematitic laterites, with acid consumption 1200 kg/t are. The effect of preheating of the laterites before leachin~ has also been investigated. Two or three stage counter-current leaching of the serpentinic laterite could reduce acid consumption to 900 kg/t ore (53 kg/t Ni) without affecting recovery.
(10:00 a.m.) PURIFICATION OF COBALT SULFATE SOLUTIONS BY SOLVENT EXTRACTION Eddie C. Chou and Leo W. Beckstead, AMAX Ext. R&D, Inc., 5950 McIntyre St., Golden, CO 80403 Commercially available cobalt metal usually contains about 1000 ppm nickel. For the production of low-nickel cobalt metal from chloride solutions, a,. process consisting of solvent extraction, ion exchange and e1ectrowinning has been developed. The objective of this study is to produce low-nickel cobalt from cobalt sulfate solutions via solvent extraction. Based on published information, four potential nickel extractants were tested for nickel removal from cobalt sulfate solutions. Of the four nickel extractants evaluated, the two most promising ones are 2-thyl-hexanal oxime (EHD) plus d i -2-ethy1 hexy1 phosphori c ac i d (DEHPA) and n-a I ky1ated bis-pico1y1amine (BPA) plus dinonylnaphtha1ene sulfuric acid (ONNSA). The organic composition containing EHO results in ani cke 1-to-coba lt separa t i on factor of about 23 a t pH 3, and phase separation is rapid at 22 oC. The extractant containing BPA has a high nicke1-to-coba1t separation factor (50 to 60 at pH 1.5 to 2.0), but extraction must be run at 45 to 50 0 C to obtain reasonable phase separation.
CREEP AND CREEP FATIGUE INTERACTION TMS-AIME General Abstract Session Mardi Gras C Wednesday, March 5,1986 Marriott Hotel 8:30a.m.
Session Chairman: John Gayda, NASA Lewis Research Center, Mail Stop 49-3, 21000 Brookpark Road, Cleveland, OH 44135
(8:30 a.m.) STRESS-STRAIN AND CREEP BEHAVIOR OF MA 754 *: E. Jacobs, A. H.
k~3~5r,Sc~~~1 J~pn M~~e~!e8;r~~~~~ 5~~ v~;~rt~~i~at;~~~l~y. ;(m~~.
High temperature deformation properties of the ODS (oxide dispersion strengthened) alloy MA754 were studied using static creep and true strain rate controlled tests. In previous work wi th the Y' strengthened IN115 alloy, an equivalence between the
;~;~~;ttgn) s~fe~s c~g~~tt~~t a w~~n~~~~ai~~: ~8ei ~~!e~g~l~~~
tween a~,Aa parameter defined as the transition from Stage II
~~e~~a~tr~;~ ~~~k ar~~d~~;~~~e~~d i~e a~e~~~i~~~s (~i~Il~~ ~~c~he
IN115 study, data for MA754 is used to confirm the presence of
paper will discuss some theoretical and practical aspects of e design and construction of the new plant. A more detailed treatment will follow the approach taken to commissioning and the technical problems encountered in practice. The plant now has achieved its desi9n cobalt production capacity on a monthly basis and the paper illustrates the modifications which have been made to make this possible.
(9:00 a.m.) J. C. Agarwal, Charles River Associates, Inc., 200 Clarendon Street, Boston, MA 02116 In many industrial situation, cobalt is extracted together with other metals. The economics of separating cobalt from these complex dilute solutions will be presented.
(9:30
a.m.~
EXTRAcrION OF NICKEL AND COBALT FROM LATERITES BY ATMOSPHERIC PRESSURE SULFURIC ACtD LEACHING: N.Panagiotopoulos, S.AgatziniLeonardou, . A. KontoDoulos, National Technical University of Athens, GR-106 82 Athens, Greece. The extraction of nickel and cobalt from greek laterite deposits by atmospheric pressure sulfuric acid leaching has been investigated. Low-grade ('Vl'%Ni) limonitic or ht2matitic type and highgrade ('\..2. 20%Ni) serpentinic type laterites have been used. The
¥~i ;e~~ai~; i gSr~ / ~8n~qt;;a~ ~~c~ur ~~~e e~~l ~~~~r~~~n~i~~rt~~1~~~on. ~~~~~;i~~dP~~~~ei~~pi~Sfu~~ ~~;~Ph~;~~~I~~:e
and to begin to
*This work is sponsored by the NSF under grant DMR8o-11402 under the monitorship of Dr. Joseph Thomas.
(8:50 a.m.) ON THE PRIMARY CREEP OF WASPALOY: W L. Kimmerle and J .K. Iien, Center for Strategi c Mater ials, Col umbi a Uni versi ty, NY, NY 10027.
Although the various factors affecting the minimum creep rate and rupture life of superalloys have been well documented, the subject of primary creep has recieved much less attention. This is somewhat surprising since for certain applications design criterial may have failure defined for creep strains as low as 0.1%. The effect of stress, temperature and gamma prime morphology on the time to reach a gi ven percent strain is reported for Waspaloy with a grain size of ASTM 6. The stress dependence of the time to reach various percent strains is shown to be similar to the negative inverse of the stress dependence of the minimum strain rate. The reported effect of gamma prime morphology variation is discussed with respect to our current understanding of the primary creep and the effect of the resisting stress in the creep of particle strengthened alloys. We thank both Wyman Gordan Company and the NSF under Grant DMRBO-11402, monitored by R. Stang, for their support of this proj ect.
TMS Annual Meeting 87 (9: 10 a.m.)
(10:30 a.m.)
CREEP-FATIGUE INTERACTION IN LEAD-TIN SOLDER ALLOYS*. R......J:&Ly
THE ROLE OF THE SURFACE LAYER ON THE POI
~,
John K. Ti en. The Center for Strategi c Materi als, Henry
Krumb School of Mines, Columbia University, NY, Ny 10027, and
Sung K. Kang, and Roger A. Pollak of IBM, T.J. Watson Research
Center, Yorktown Hts., NY, 10598.
Cyclic creep and stress rupture results of lead-tin alloys were studied as a function of frequency or hold time, mean stress, and second-phase volume fraction at 25 C. The mechanical test specimens were cast and machined into a 1 inch gage length and .25 inch gage diameter which were then tested on a computer controlled servo-hydraulic MTS testing machine. Tensile, cyclic creep, and stress rupture results are also reported for a Simple butt joint configuration. Upto a factor of 5 decrease in the minimum strain rate and a doubling of the rupture life were found to accompany an increase in cyclic frequency from 0 to 100 cycles per minute, for both the bulk and the joint eutectic alloy specimens. Cyclic creep and stress rupture resistance, as expected, decreases with increasing mean stress. Increasing the volume fraction of the Pb phase is seen to decrease the stress rupture resistance. The unexpected decceleration of the creep rate is proposed to be related to the anelastic strains recovered during the off-load periods. Extensive metallography includes compl ete mi eros t uct ural character i za t i on, fracture analysis, and TEM.
~ThiS
Metallurgical Materials Laboratory, University of Haryland. College Park, MD 20742. The dislocation density as computed from X-ray line broadening analysis was measured in the surface layer, Ps' and the interior, Pi, of Al 1100 specimens crept at high temperatures. The power law breakdown occurred when Ps > Pi. In the power law breakdown region, Os increased rapidly with strain and stress while Pi increased with stress to a higher plateau levels. The recovery process consisted of two stages: a rapid stage with an activation energy of 14.3 kJ/mole and a slower stage with an activation energy of 127.9 kJ/mole. The recovery process was the same for specimens crept within and above the power law region.
*
This research was s,upported by a grant from the National Science Foundation mm 81-0B422-A03.
work was sponsored by the IBM Corporation.
(9:30 a.m.) MATERIAL CHARACTERIZATION OF SUPERPLASTICALLY FORMED TITANIUM6Al-2Sn-4Zr-2Mo SHEET: William A. Ossa*, and Dick M. Royster, NASA-Langley Research Center, MSj189. Hampton. VA 23665-5225.
(10:50 a.m.) HIGH TEMPERATURE STRENGTHENING K. Vedula and C. M. Michal,
Materials Science,
The aerospace industry has focused considerable interest on the near-al pha titanium alloy Ti-6Al-2Sn-4Zr-2Mo (Ti -6242) because of both its high temperature properties and its superplastic forming (SPF) capabil ities. This paper describes current research to characterize selected mechanical properties of Ti6242 sheet in the superplastically stretched condition, both with and without heat treatment, and compares the results wi th those obtained on as-received material. Tensile and creep tests were conducted. and metallographic analysis was performed to show the effect of SPF on titanium properties. Preliminary analysis shows that, due to SPF processing, tensile strength drops 5 to 12 percent at room temperature. and 8 to 12 percent at 600 0 F. Creep tests at 800 0 F and 10000F show the SPF processed material displays superior creep resistance compared to as-received material. A post SPF duplex anneal heat treatment had no beneficial effect on tensile and creep properties. *PRC Kentron. Inc .• 3221 N. Armistead Ave .• Hampton. VA 23666.
OF
B2
NiAl,*
V.
M.
Pathare.
Department of Metallurgy and Case Western Reserve University, Cleveland,
OH 44106.
Precipitates of ternary intermetallic compounds of NiAl with Ta and Nb have been found to provide very significant strengthening in NiAl matrix at 1300 K. The crystallography and the orientation relationships between these precipitates and the NiAl matrix have been investigated by Transmission Electron Microscopy. The precipitates, however, are found to coarsen during high temperature, slow strain rate deformation. The mechanism of strengthening and the limitations due to coarsening will be discussed.
*
Research supported by NASA-Lewis Research Center, Cleveland,
OH.
(11: 10 a.m.) (9:50 a.m.) DISLOCATION-FREE ZONE AHEAD OF CRACK TIP IN BCC METALS:* C. G. Park and S. M. Ohr, Sol id State Division, Oak Ridge Nation-a-lLaboratory, Oak Ri dge, TN 37831 Electron microscope studies have been made of the distribution of dislocations ahead of propagating cracks in bcc metals during in situ deformation. Dislocations emitted from the crack tip are piled up in a plastic zone, usually in the form of a linear array, wi th a di s 1ocat i on-free zone (DFZ) between the crack and the plastic zone. The size of the DFZ (1 " 20 ~m) depends on the number of dislocations in the plastiC zone. the grain size of specimen and the loading conditions. As the applied stress increases, the DFZ size decreases. The DFZ ahead of the shear crack of mode I I lis small er than those of mode I and mode I I cracks. The effects of unloading and hydrogen environment on the DFZ. as well as the dislocation distribution, have been also studied. The results are discussed in terms of the dislocation theory of fracture. *Research sponsored by Dlvision of Materials Sciences, U. S. Department of Energy under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.
CREEP-FATIGUE INTERACTION OF CAST AND WROUGHT SUPERALLOYS IN SALT AND AIR ENVIRONMENTS': Erik Schwarzkopf. Jerry Stefani
~ggo~~h~f KMi~~~7' cgi8~g~ afa~~~fi~~ CN~~t~~;~:s NY He?SD2~rumb
In this study the creep-fatigue interaction is evaluated in both air and salt environments for two uncoated nickel-base superalloys I wrought Udimet-720 and cast-Hi pped Inconel 738. In addition, characteristic S-N curves for the materials in both environments were obtained via positive R stress-controlled fatigue tests at a temperature and mean stress of 704°C and 70 ksi, respectively. To separate creep and fatigue effects. constant maximum stress tests were performed for various mi nimum stresses i ncl udi ng the pure creep condi ti on of a ' equal to a x' Results show a significant reduction in min fatigue liiRg for these statically corrOSion resistant materials tested in a salt environment compared to air, at both low and high amin stresses. Scanning electron microscopy studies indicate that the salt environment attacks grain boundaries
~~~r~~~ n~at~u~~~ ti~;~~n t~~ t~~n~~~n~h~~~r~~ i~~~~s~r~~~~rf~uI~r
possible to map fracture modes of initiation and propagation in terms of fatigue stress parameters. *This work is sponsored by a Special Metals Corporation/Kelsey Hayes research gift.
(11:30 a.m.) (10: 10 a.m.) CREEP BEHAVIOUR OF Ni-Cr ALLOYS WITH TRACE ADDITIONS OF Ce*: P. Latham and F.Cosandey, Department of Mechanics dnd Moterials Science, Rutgers University. P.O. Box 909. Piscataway, NJ 08854.
THE EFFECT OF PACK ALUMINIZED COATING ON THE CREEP BEIlAVIOR OF RENE' N4 SINGLE CRYSTAL:' M. Khobaib. University of Dayton
Research Institute, Dayton, Ohio, and T. Nicholas, AFWAL/MLLN, Wright-Patterson AFB t Ohio
The creep behaviour of a 80Ni-20er alloy with trace additions of Ce ranging from 0 to 119 at. ppm has been investigated at 700°C. The alloys rupture strain increases from 0.17 to 0.49 with increasing Ce content. These variations are also accompanied by changes in fracture mode from intergranular to transgranular. The stress exponent of the minimum strain rate is largest for Ce containing alloys with, at high stress, all the stress vs. strainrate curves converging to orle pOint. This point corresponds to the critical lowest strain rate for which all alloys fracture transgranularly regardless of Ce content. These results will be discussed in terms of grain boundary sliding induced cavitation with particular attention to the role of grain boundary segregation in cavitation processes.
Single crystals of .,( precipitation hardened Rene' N4 with tensile axis parallel to [001] were tested under sustained load in the temperature range' of 1400-2000°F. The influence of coating was studied by conducting similar tests with bare and coated specimens in laboratory air and tests on bare samples in vacuum. It appears that the coating influences creep rupture life only at higher temperatures by limiting the surface oxidation, since little difference in rupture life was found up to 1600°F where oxidation is negligible. Fractured surface of the specimens indicated that the initiation of crack was more or less random. In some cas,es, the crack initiated from the internal pores, while the surface cracks were also found in other specimens. TEM observations showed a complex substructure of stacking faults within y"' precipitate along with dislocation networks on the interface. At higher temperatures above 1800 o F. the shearing was mainly by a/2 <110> dislocations.
*This research is supported by the National Science Foundation.
*Work Sponsored Under
u. S.
Air Force Contract No. F336lS-84-C-50S1.
88 TMS Annual Meeting
DEFORMA nON PROCESSING TMS-AIME General Abstract Session Wednesday, March 5,1986 Regent 8:30a.m. Marriott Hotel Session Chairman: T. R. McNelley, Materials Science Group, Dept. of Mech. Engr., Naval Postgraduate School, Monterey, CA 93943
(8:30 a.m.) MODELLING OF SUPERPLASTIC FLOW BEHAVIOR IN A K. B. Hidalgo-Prada and A. Ti-6Al-4V ALLOY: Department of Mechanical Engineering. Univ. of Davis, CA
Ni -MOD I F I ED Mukherjee. Ca 1 iforni a,
The effect of microstructural evolution on the superp1astic flow behavior of aNi-modified Ti-6Al-4V alloy. as it affects the correlation between flow stress and strain rate. has been examined. In particular. conditions for maximum ductflity. denpendence of flow stress on strain and effect of the dual-phase nature of the alloy. are detailed. It was determined that microstructural changes during superp1astic deformation introduce significant variations in the phencmeno10gica1 parameters of the physical constitutive equation due to factors such as phase size growth. phase size refinement and interphase accommodation. The kinetics of phase evolution and the mechanisms responsible for the observed flow behav i or are deta il ed and corre 1ated wi th ex is t i ng mode 1s for micrograin superp1asticity in two-phase alloys. Research supported by USAF-AFOSR Grant No.
82-0081
(8:50 a.m.) THE EFFECT OF RECRYSfALLIZATION AND Gl
T. R. McNelley and T. S. Hartman, Materials Group, Naval Postgraduate School, Monterey, CA 93943; E. -W. Lee, Naval Air Development Center, Warminster, PA 18974, USA Thermomechanical processing of AI-IOMg-O.l Zr by warm rolling at 3000C develops a fine sub grain structure in conjunction with refined precipitate dispersions of SMg and Bz r . Superp!astic deformation at 300 D e results from continuous recrystallization, th concurrent coarsening of substructure and growth of recrystallized grains. The activation energy is that for self- or Mgdiffusion for temperatures above and below the superplastic regime, and is very low in it j this is shown to resul t from microstructural instability by comparing behavior with that of recrystallized, coarse-grained condition of the
Research supported by U.S. Naval Air Systems Command.
DUCTILITY IN 7475 ALUMINUM BY THERMOMECHANICAL PROCESS-
E.-W. Lee, Naval Air Development Center, Warminster, PA 18974; A. Garg and T. R. McNelley, Materials Science Group, Department of Mechanical Engineering, Naval Postgraduate School,
ing particulate content. A simple micromechanical model of flow is developed for these materials which takes into account particulate interaction effects as well as the resistance to grain boundary sliding. Comparison against actual test results will be presented.
(9:50 a.m.) EFFECT OF MATRIX STRENGTH ON THE STRENGTHENING OF SIC! AL COMPOSITES* R. J. Arsenault, Metallurgical Materials Laboratory, University of Maryland, College Park, MD 20742.
It has been observed that as the strength of the matrix increases, e.g., due to alloying or age hardening, the percentage increase in yield or ultimate tensile strength decreases for a given volume percent SiC/AI composite. If the matrix is 1100 Al and 20 V% SiC whisker is added, then there is a 500% increase in strength, whereas, if the matrix is aged 7075 Al alloy, there is a 10% increase in strength. If the absolute magnitude of the increase is considered, again in the case of a 1100 Al matrix composite, the increase is greater. The basic reason for this difference in strengthening is due to the chanp,e in magnitude of the dislocation density and of the tensile residual stress. In the case of the 1100 matrix, there is a maximum dislocation generation due to differences in coefficients of thermal expansion and a minimum tensile residual stress, because the yield stress of the 1100 matrix is much less than the yield stress of the 7075 matrix. * This research was supported by the Office of Naval Research under Contract No. N00014-85-K-0007.
(10: 10 a.m.) EFFECT OF STRESS TRANSIENTS ON FORMABILITY: Kwansoo Chung, and R. H. Wagoner. Department of Metallurgical Engineering. Ohio State University. 116 West 19th Avenue. ColumbUS. Ohio 43210. Metals and alloys often exhibit a transitional stress-strain region following abrupt changes in strain state or strain rate. These regions may usually be characterized by a positive stress increment and lowered >!ork-hardening rate or a negative stress increment with enhanced work hardening rate. The behavior subsequent to these transients has been investigated by Finite Element Analysis of a sheet tensile test. This analysis shows a clear degradation of formability with the first type of transient and little effect with the second. The origin of the effect on formability lies in the transient work-hardening rate. not in the sign of the stress change.
(10:30 a.m.) WARM WORKING OF NICKEL: Y.W. Kim and D.L. Bourell. Center for MS&E. Department of Mechanical Engineering. The University of Texas. Austin. TX 78712 Commercially pure nickel was thermomechanically processed by rolling to reductions in thickness as high as 87 percent at room temperature. 200°C and 300°C. Tensi on tests were performed on pos t-processed rna teri a 1s. It was observed tha t the opt imum combination of strength and ductility was obtained for materials receiving large working strain at elevated temperature. This effect is associated with the formation of a recovered homogeneous structure and a minimum of shear localization in the form of microbands or transition bands. Texture measurements. transmission electron microscopy and differential scanning ca10riometry were used to correlate structure to the observed tensile behavior. This research was funded· by NSF Grant DMR 8113087.
*
, CA 93943. USA
thermomechanical process, concluding with rolling to a large strain at a wann (300 0 C) temperature, has been shown to confer superplastic response in high-Mg, AI-Mg alloys. The 7475 alloy has been warm-rolled, with or without an initial averaging treatment. The resultant structure consists of a sub grain structure in conjunction with a dispersion of precipitates. Substantially increased ductility compared to untreated material has been attained in subsequent tension testing at 300°C. Resultant structures were non-uniform, however, as a result of a non-uniform precipi tate dispers ion. Research supported by U.S. Naval Air Systems Conunand.
(9:30 a.m.) SUPERPLASTIC CREEP IN METAL-CERAMICS COMPOSITES: A. K. Ghosh and
M. W. Mahoney, Rockwell International Science Center, Thousand Oaks, CA
91360
The stress-strain rate relationships of a series of SiC particulate reinforced supEtrplastic Al alloy (PM-64) composi tes have been studied. It has been found that within the superplastic temperature and strain rate range, the effect of the particulates is not only to elevate the stress level for superplastic flow but to resist the operation of diffusional creep. This view is supported by the loss of a high strain rate sensitivity region and the appearance of a threshold stress like behavior with increas-
(10:50 a.m.) CHARACTERIZATION OF ACOUSTIC EMISSION SOURCES IN METAL CUTTING
PROCESSES: Minvoung Lee, Steven R. Hayashi, Douglas C. Wildes, General Electric Company, Corporate Research and Deve]opment, Schenectady, NY Two types of acoustic waves are generally observed from metal cutting processes, one being a continuous wave of broad range of frequency and the second being spiky pulses appearing randomly superimposed on the continuous wave. The continuous wave is directly related to the shear deformation process of making chips and the RMS level of acoustic energy, generally proportional to the energy required to cut a given metal. The origin of randomly appearing spikes are much more complex and often indicate the status of cutting edge. In this study the sources of high energy pulses in AE signal were investigated in relation to the type of metals, cutting tool material and its surface conditions and cutting geometry. In addition to monitoring of AE, the experimental approaches included simultaneous monitoring of forces, low frequency vibration of the systerr, and ship flow using a high speed video motion analysis system. The paper will describe various specific sources of pulses in the AE signal.
TMS Annual Meeting 89 (11: 10 a.m.)
THE EFFECT OF STRAIN STATE ON VOID DISTRIBUTION AT TEAR BY PUNCH STRETCHING IN LOW-CARBON, AK, DQ STEEL" S.J Shaffer J.W. Morris, Jr, Lawerence Berkeley Laboratory, Berkeley, Ca. Void distribution at the failure region in a set of Low Carbon Steel AK DO LDH specimens is investigated by SEM in both plane and cross section and the effect of strain state is examined. Correlations between void shape, Size, and distributions are made as fuctions of distance to fracture edge and strain. Both macroscopic and microscopic strains are compared in this regard. The distribUtion of voids was found to be the result, rather than the cause of failure in this examination. A discussion of the relevance of both the testing method and material used on the results Is Included. *This work was supported by the U.S. Department of Energy, BES contract "'DE -AC03-76SF00098.
ELECTRONIC AND MAGNETIC MATERIALS TMS-AIME General Abstract Session Wednesday, March 5,1986 Mardi Gras H Marriott Hotel 8:30 a.m. Session Co-Chairmen: G. W. Warren, Dept. of Met. Engineering & Matis. Sci., Carnegie-Mellon University, Pittsburgh, PA 15213; and Stuart R. Stock, School of Matis. Engrg., Georgia Institute of Technology, Atlanta, GA 30332
(8:30 a.m.) SOLIDIFICATION OF HgCdTe: Ching-Hua Su", F. R. Szofran"", and s. L. Lehoczky**, *Universities Space Research Association ViSiting Scientist, **Space Science Laboratory, NASA Marshall Space Flight Center, HuntSVille, AL HgCdTe mel ts are solidified under a well-defined thermal condition using a two-zone furnace. The compositional variations along the radial and axial directions are determined by IR transmission, ED X, and density measurements. The results are compared with a recent theoretical calculation by Alexiades et a1. They simulated the solidification process by considering both heat conduction and solute dif fusion and using the experimental thermodynamic and therrnophysical data of Hg-Cd-Te system. The experimental evidence of Stoke' 5 migration of the second phase in a gravitational field 15 also presented. *Work supported by NASA Microgravity Science and Applications Division.
developed potential step test. The devices used were vapor deposited Cr-Cu-Cr metallization, 60 to 200 "(.1m in width, on an alumina substrate, with spacings varying from 70 to 180 wm. The short circuit potentiaLs observed in the step test were found to increase with increasing pH. rhe morphology of the dendrites was also observed to vary with the metals depOSited on the cathode and the pH value of the electrolyte. Cyclic voltammetry was also performed on both the substrate and pure metals for comparison. Copper and the Pb-Sn solder were found to play an important role in dendrite formation. Relationships between the cyclic voltammetry experiments and the potential step test are discussed. Results indicate that these experimental techniques can provide useful information concerning the electrochemical degradation processes which occur on the metallized substrate.
(9:30 a.m.) LOW-TEMPERATURE SPECIFIC HEAT OF (Co7SFe22hV:" A. DasGupta, D. M. Kroeger, G. M. Stocks, and C. T. Liu, Oak Ridge National Laboratory, P.O. Box X, Oak Ridge, TN 37831 Low-temperature speCific heat was measured in both ordered and disordered samples of (Co7sFe22)3V between 2 and 12 K. The experimental results exhibited three anomalies: (1) the specific heats are linear in temperature in this temperature range with non-zero offsets when extrapolated to 0 K, (2) the slopes of the above straight lines are unusually high (1. 27 x 10- 2 and 1. 84 x 2 10- J/mole K for the ordered and disorderd states respectively), and (3) there is no evidence of the r 3-term in the specific heat data although the Debye temperature was estimated to be 508 and 473 K from elastic constants data for the ordered and disordered states respectively. Possible reasons for the above anomalies will be discussed. *Research sponsored jointly by the Division of Materials Sciences, and the Office of Energy Utilization Research, Energy Conversion and Utilization Technologies (ECUT) Program, U.S. Department of Energy under contract DE-ACOS-840R21400 with Martin Marietta Energy Systems, Inc.
(9:50 a.m.) ELECTRONIC PROPERTIES OF THE DIRECTIONALLY SOLIDIFIED Al-In-Sn *M.K. Wu, *J.R. Ashburn, **P.A. Curreri, and +W.F. Kaukler, *+ University of Alabama in HuntSVille, Huntsville, AL 35899 ** Space Science Laboratory, NASA/Marshall Space Flight Center, HuntSVille, AL 35812 AI-In-Sn alloys have been directionally solidified in the NASA KC-135 aircraft which flies a series of parabolas to generate high(hi-g) and low(lo-g) gravity forces parallel to the long itud inal growth ax is. Measuremen ts on the electronic propert ies of the samples reveal that: 1) the resistiVity of the 10-g sections is 50 times larger than that of the hi-g sections; 2) the 10-g sample behaves 1 ike a semi-metal, while the hi-g sample is essentially metalliC; 3) the superconducting transition temperature of the lo-g sample is one degree higher than that of the hi-g one. Results will be presented and discussed in comparison with the detail microstructure. *Work is supported by the NASA Grant No. NAG8-032 and Research Institute of the University of Alabama in Huntsville. **Work is supported by the NASA Microgravity Sc ience and Application Division.
(8: 50 a.m.) THE EFFECT OF GROWTH RATE ON THE COMPOSITIONAL VARIATIONS IN DIRECTIONALLY SOLIDIFIED Hg Cd Se ALLOYS: R.N. Andrews, University of Alabama at Bitm1ng~am, Birmingham, AL, F.R. Szofran, A.M. Dorries, R.P. Harris and S.L. Lehoczky, Space Science Laboratory, NASA/MSFC, Huntsville, AL Several Hgl_xCdxSe crystals of composition x=0.2 were grown in a Bridgman-type directional solidification furnace at furnace translations varying from 0.15 microns/second to 0.4 microns/seconds. The influence of growth rate on both the longitudinal and radial compositional uniformity for the crystals was determined using density measurements and infrared transmission edge mapping. Comparisons between the measured longitudinal profiles and the theoretical model for a one-dimensional diffusion case were in reasonably good agreement. Radial compositional variations were highly dependent On the various growth parameters. These results will be discussed in terms of the thermodynamic and thermophysical properties of the materials and the relevant heat and mass transfer parameters. «work supported by NASA Mictogravity Science and Applications DiVision and by NASA/Summer Faculty Fellowship/ASEE.
(10: 10 a.m.) SANS Characterization of PreCipitation in a Cu-O.S%' Co Alloy.* Stephen Spooner, Solid State Division, Oak Ridge National Lab., Oak Ridge, TN 37831. An alloy of Cu-D.s % Co aged at 560°C, 580°C, and 600°C for 1, 2, and 3 hours was examined with small-angle neutron scattering with the object of characterizing nucleation and growth stages of precipitation.. Particle number densities are evaluated and estimates of nucleation rates are being made. The precipitate interface is expected to have a finite width under the conditions studied, however, anticipated scattering effects were obscured by other sources of diffuse scattering. *Research sponsored by the National Science Foundation Grant No. DMR-7724459 through Interagency Agreement No. 40-636-77 with the U. S. Department of Energy under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.
(10:30 a.m.) (9: 10 a.m.) AN EXAMINATION OF THE FAILURE OF ELECTRONIC DEVICES BY CYCLIC VOLTAMMETRY AND POTENTIAL STEP METHODS; B.D. Yan, G.W. Warren and P. Wynblatt, Dept. of Metpllurgical Engineering and Materials Science, Pittsburgh. FA '15213 Environmental failure of the electronic devices often occurs due to as soc ia ted corras ion and depos i t ion processe s uncle r a ppl ied bias which results in the growth of dendrites and subsequent short circuit. As a preliminary step toward determining the mechanism of failure, devices have been immersed in various electrolytes and subjected to cyclic voltammetry and to a specially
DECOMPOSITION OF 3 -COBALT ALUMINUM ALLOYS AND MAGNETIC HARDENING: A. Zeltser and W.A. Soffa, Department of Materials Science and Engineering, University of Pittsburgh, Pittsburgh, PA. 15261 Cobalt-aluminum alloys containing approximately 15 weight percent aluminum can develop excellent permanent magnet properties which apparently derive from elongated single domain particles of a cobalt-rich phase which forms during aging of the beta (B2) Co-AI matrix. Coercivities of 1000 Oe and greater are readily attained in the heat treated alloys. In this study transmission electron microscopy (TEM) has been employed to study the trans-
90 TMS Annual Meeting formation of the S -phase and the relationship between the microstructure and magnetic hardening. An omega transformation has been found to occur in the parent phase during quenching.
Standards (NSPS). These standards are designed to primarily control fluoride emissions as a secondary welfare pollutant. Since that time, three new primary aluminum sources have been constructed in the US, and they are currently regulated under NSPS. They are the 60,000 S.T. Alcan Sebree Potline (1978),
(10:50 a.m.) DEVELOPMENT OF TIlE Nb 3 Sn LAYER MORPHOLOGY IN BRONZE-PROCESSED
SUPERCONDUCTORS:· !L..&.. Dietderlch and J.W. Morris. Jr •• Dept. of ~lat. Sci. and Min. Eng q Univ. of Calif., Berkeley, Lawrence Berkeley Laboratory. Berkeley, CA 94720. Prior work on bronze-processed wire and its variants has shown that the grain structure in the Nb Sn layer can be sub-divided 3 into distinct morphologies: columnar. equiaxed. and coarsegrained. Some or all of these grain morphologies may be present in a particular conductor. The microstructural development can be understood in terms of the volume expansion that occurs when Nb is converted to Nb Sn. This expansion produces stresses 3 through the Nb Sn layer that have profound effects on the grain 3 morphology. Minimization of strain energy provides a driving force for the formation of dislocations and a preferred growth orientation. ·This work is supported by the Office of Basic Energy Sciences, Materials Sciences. Division of the U.S. Department of Energy under Contract Number DE-AC03-76SF00098.
(11: 10 a.m.) ELASTIC STRAIN FIELD MEASUREMENT IN A NOTCHED SILlCON CRYSTAL:
S.R. Hedayat, S.R. Stock. School of Mat. Eng., Georgia lnst. of Technology, Atlanta, GA 30332, and G.E. White and Haydn Chen, Dept. of Met.Min.Eng .• Univ. of Illinois. Urbana, lL 61801 Four terms ou( i) / 6x (j) of the s train tensor ( i j ) wer~ determined as a function of position around a notch in an elastically bent silicon crystal. The strain field around the notch was mapped using absorption edge contours (A.E.C.) produced with synchrotron white radiation. A niobium filter placed before the specimen was used to form the AEC on x-ray topographs: the abrupt change in intensity transmitted through the filter resulted in a sharp contour when the silicon crystal was oriented to diffract a range of wavelengths near the filters absorption edge. Contour positions were mapped for two orthogonal diffracting planes, and the effect of the discontinuity on the local strain field was clearly evident.
the 200,000 S.T. Alumax
Mt Holly Plant (two potlines 1980). & the 85,000 S.T. Noranda New Madrid Potline (1983). All three plants were constructed utilizing Alcoa electrolytic reduction cell technology. This paper provides details of the extensive emission test results from each of these plants. The tests show general compliance with NSPS, although considerable variability is observed between the plants. and even within a plant. over long periods of time. This variabi1-
~~~ Bfl~~rjOa~~mr~~~g~~~~ge~? the regulation and permitting of
(10:15 a.m.)
Break
(10:30 a.m.)
ADVANCES IN UNDERSTANDING THE EFFECTS OF ATMOSPHERIC FLUORIDE ON
VEGETATION: D. C. MacLean, D. C. McCune, L. H. Weinstein, and J. A. Laurence, Boyce Thompson Ins ti tu te, Ithaca, NY 14853 Vegetation is extremely susceptible to atmospheric fluorides, and the first effects were probably the result of fluoride emissions during volcanic eruptions. It has been suggested that the earliest problems associated with man I s activities arose when clay was first baked to make bricks. By the mid 1800's damage to vegetation from industrial fluoride emissons was well documented. Initially, these sources were uncontrolled, & with time & technological advances, control of emissions became more & more effective. Research on the effects of fluoride on vegetation generally fcnav.e:l this progressive improvement. The earliest work focused on gross effects from acute exposures whereas today the responses of concern are the subtle or indirect effects of fluoride. This paper provdes an historical review of research on the effects of fluoride on vegetation & how knowledge gained in this way, contributes to our present understanding of the topic & directs our attention to areas where additional informaLlon is required.
(11:15 a.m.) THE DRY SCRUBBING OF ANODE BAKE OVEN FUMES PROBLEMS
& SOLUTIONS:
P. M. Dumortier, P. Aubry. Air lndustrie Environment. Paris. France. G. Gaspard. Air Industrie Australia, Sydney, Australid, G. Magnin, Procedair lndustrie, Montreal, Canada. While the dry scrubbing of anode bake oven fumes is similar to the process used for the pot gases it presents some difficulties which must be mastered to ensure a smooth & reliable operation.
RONMENTAL CONTROL & HEALTH I Sponsored by the TMS Light Metals Committee Pontchartrain Ballroom B lWednesday, March 5,1986 Sheraton Hotel Chairmen: S. G. Epstein, Aluminum Association, ashington, DC 20006; and R. C. Dickie, Alumax, Mt. Hol, SC 29445
CONTROL IN THE ALUMINUM INDUSTRY 100 YEARS OF
Patrick R. Atkins, Aluminum Company of America, 1501 Building, Pittsburgh. PA 15219
r1l:'..LtiNULUGY:
is the byword of the 80 I s~ and two areas where change is t apparent are technology and social responsibility. It is t appropriate to talk about these subjects in the context of the aluminum·industry since the two are so closely linked. The aluminum industry was found on a technological breakthrough that occurred 100 years ago; and since that time, the culture of the industry has encouraged continued technology advancement in production, fabrication, use and reuse. This technology thrust has also included environmental management to an extent unparalleled in other basic industries. Environmental control has now become such an integral part of the aluminum production process that all new reduction facilities constructed throughout the free world utilize "state-of-the-art" fluoride control systems that are direc tly lined with the production process. Fluoride control has come of age in the aluminum industry not only in environmental control but also in the technology development programs that have E~gd~:fi~dw5~rd ~ighly ef f icient reduc tion facilities used through-
(9:30 a.m.)
COMPLIANCE WITH U. S.f EPA PRIMARY ALUMINUM NEW SOURCE PERFORMANCE
STANDARDS: R.C. Dickie~ Alumax P.O. Box 1000, Goose Creek, SC 29445~ B. Clark, Alcoa Alcoa Building. Pittsburgh, PA 15219, H. Givens, Alcan Ingot & Recyc·ling, Box 44. Henderson, KY 42435, R.E. Hurt, Noranda Aluminum Inc Box 70, New Madrid, MO 63869 Passage of the US Clean Air Act & its 1977 Amendments requires new primary aluminum sources to comply with New Source Performance
The problem of fumes cooling is the most important. Tar must be condensed before scrubbing. This is achieved in a tower in which the water injected must be totally evaporated. Improvements had to be brought to the Tomago plant to overcome the corrosion occuring a t the top of the cooling tower. A new solution has been found which is very promising. Five such installations are being built & three are operating. Scrubbing and operational results are given.
EXPERIMENTAL METHODS FOR MICROGRA VITY MATERIALS SCIENCE RESEARCH V Sponsored by the Thermodynamic Data Committee, Materials Science Division, American Society jor Metals Wednesday, March 5,1986 Mardi Gras F-G Marriott Hotel 8:30 a.m. Chairman: R. A. Schiffman, Midwest Research Institute, Kansas City, Missouri 64110 Session Chair: E. H. Trinh, Jet Propulsion Laboratory, Pasadena, CA 91109
(8:30 aom.)
HIGH TEMPERATURE HEAT PIPE AND ELECTRON BEAM HEATING FOR SPACE APPLICATIONS: P. Behrmann, ESTEC, Noordwijk, The Netherlands, J. Schawer, MBBfERNO, Bremen, W-Germany. High temperature heat pipe and electron beam heating is currently being developed within the European Space Agency's Technology Research Programme. The heat pi pe furnace features a gas-stabi1ized Molybdenum/Rhenium coaxial heat pipe with Litium as working fl uid. Heat pi pe pressure is moni tared for temperature control. The furnace shall allow highly isothermal operation up to 1773K. In the EB furnace a number of electrostatic and magnetic deflection units are used to scan the beam generated by a point cathode across the surface of a cylindrical sample. This allows one to generate very high sample temperatures up tON 2300K and to tailor heat input profi les to specific experiment requirements. The
TMS Annual Meeting 91
paper will present the general layout of both furnaces. Anticipated performance characteristics will be backed up by first breadboard resu 1t s.
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SURFACE FORCES AND ADHESION IN CONTACTING SOLIDS: • G. Poletti,
1st. Fisiol. Gen. e Chim. BioI., Universita di Milano,Milano,Italy.
A dynamic technique to measure surface forces in contacting solms is 9,iscussed toghether with an experiment included by ESA in the payload of the EURECA flight. The main objectives are the measurement of surface force and surface energy in the contact area between real bodies and the assesment of their dependence of mechanical and physical parameters. A small sphere impacts against a target and time behaviour of contact force, contact time and resti tution coeff'icient are measured as a function of the incomirg sphere veloci ty. Computer simulation of the experiment indicates that surface force effects can be measured provided the experiment is carried out in microgravity under ultra high vacuum. The characteristics of the experiment and of the facility designed to fly on board of Eureca in 1988 are shown. Potentialities of this new technique for microgravi ty material science research are discussed
* This work is financed by the Italian
PSN-CNR.
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PLANNED DIRECTIONAL SOLIDIFICATION CRYSTAL GROWTH OF HllJ -x C
IN SPACE: *S.L. Lehoczky and F.R. Szofran, Space Science Laboratory, NASA Marshall Space Flight Center, Huntsville, AL Problems associated with the solidification and cyrstal growth of solid-solution semiconducting alloy crystals in a terrestrial environment are described. In particular, a detailed description is given of the results for the growth of mercury cadmium telluride (HgCdTe) alloy crystals by directional solidification. Results are given for a series of crystals for a wide range of growth rates and thermal conditions. The compositional variations in the crystals are related to compositional variations in the melts that can result from twodimensional diffusion or density-gradient driven flow effects ahead of the growth interface. These effects and the requirements placed on the flight solidification system are discussed in terms of the alloy phase equilibrium properties, the recent high temperature thermophysical data for the alloys, and the highly unusual heat-transfer characteristics of the alloy/ ampule/furnace system. A brief description of the planned flight hardware will also be ~iven. e and -Wort has been sllgqO[ ted by t e N1<3A Microgravity Scienc Appl catlons UiVl on.
(10:44 a.m.)
EXPERIMENTS ON THERMOCAPILLARY (MARANGONI) CONVECTION UNDER NORMAL- AND MICROGRAVITY IN AN OPEN BOAT CONFIGURATION: ~~~recht, D.Schwabe and A.Scharmann; I.Phys. Inst. Universitaet D-63 Giessen, H.-B.-Rino 16, FRG. In an open boat configuration (rectangular-cuvette made from quartz glass) the flow field and velocity distribution will be investigated under microgravity conditions (Space Shuttle Dl Mission October 1985). In the experiment MARANGONI BOAT KONVEKTION (MKB) a 2x2x2 cm melt of n-Tetracosane (C ~H ) with a free surface is
~~8~/~mfr~~r!~~e~i~:~ari!~ ~~mi~~a~~~: ~~~~!~~~Su~~e;o
microgravity only thermocapillary forces occur. In our investigations under normal gravity, the combined action of thermocapillary and bouyancy forces was established and the flow field, velocity and temperatur distributions were measured. Evidence was found, that flow and isotherms near the melt surface were influenced by thermocapillary forces in both cases. The mutual influence of bouyant and thermocapillary forces in this experiment is discussed.
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The MUL Tl-FURNACE ASSEMBLY: J. Schawer (MBB/ERNO), and W. Jansen (ESA/ESTEC). The Multi-Furnace Assembly (MFA) is a reusable experiment facility that can accommodate up to 20 furnaces for materials processing under microgravity conditions. It is part of the core payload on ESA's European Retrievable Carrier mission in 1988. The MFA consists of a structure housing the data handling, power and thermal subsystems, and the software to operate isothermal and grad i ent furnaces. It prov ides 32 pu I se width contro I led power connections for heaters and/or motor drives, with paral lei operat ions of up to 4 outputs and 230 W net furnace power (600 W for heat-up). It offers 128 signal lines for temperature recording and control. A freon cooled cold plate attached to the MFA furnace platform offers a stable heat sink. Experiment parameter changes can be uplinked during the on-orbit operations of the MFA.
FORMING OF COATED AND CLAD MATERIALS I Sponsored by TMS Shaping and Forming Committee Wednesday, March 5,1986 8:30a.m. Session Chairman: Lee Semiatin, Metalworking Section, telle's Columbus Laboratories, 505 King Avenue, Columbus OH 43201
(9:39 a.m.)
The GFQ - A FACILITY FOR DIRECTIONAL SOLIDIFICATION OF METALS IN A
LO~-GRAVITY [NVIRON~"ENT.
H. Lenski and W. t·1artin,Dornier
System, Friedrichshafen, W. Klein, DFVLR-PT, Koln. The gradient heating facility with quenching device (GFQ) has been designed for directional solidification of Al-alloys at hi gh temperature gradi ents. Quenchi ng of the specimen provi des i nformati on concerni ng materi a 1 transport in the 1 i qui d phase near the s/l-interface. The facility design is presented and thermal performance data during ground and spaceflight operation (Spacelab Dl-mission) are discussed.
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Break
(10:21 a.m.) AUTO::ATED Al'PAr.ATUS Forr PI:OTU:; Cf.YSTAL errOl!T]] I;, SPACE
FLIGI!Tp':Z. R. I\orszun, P. Todd, L. r.oc\{, and J. ~:. Cassante, University City Science Center, Philadelphia, FA. Protein crystallization experi);]ents in nicrocravity rCfIuire autonation, non-turbulent transfer of precipitant, initiation of Crovth durinc r.1inimtu:1 acceleration, tenperature control, r:::ultiple trials, and retention of crystals upon landinG. An autoPlated crystal Grm,'th device has underc,one prelininary testinc. It consists of t\:o teflon blocks, each containinG 140 Hells i.itl! a capacity of 0.1 1:11. The Hells in one bloc]\. are filled ~,'ith precipitant solution, and the wells in the other are closed at one end Hith an Ar::icon (,el) nenbrane and filled Hith protein solution. The blocks are held in an offset position so tile ,,'ells are closed until the initiation of crystallization. An electric Dotor rotates a CaJ:l Hhich. aligns the l.,re11s. Precipitant diffuses throuGh the l.1er:branes. In the absence of convection, crystals should crm,' rapidly to near-;'1axinun size and renain in tbe Hells until 1anrlinr.,. This syste:-: \"ill function in a "Get Away Special" payload or in a Space Shuttle nid-deck locicer. ~': \:ork supported by ;\ationa1 Aeronautics and Space Mlnin.
(8:30 a.m.)
GROOm: TECHOOlilGY OF CLAD AND alATED MATERIAlS, John B. Ularn, Sr.
Clad ~tals, Inc., R.D.lI2, Canoosburg, PA 15317. Many patents exist in the field of coated or clad metals, but nost differ in concept and manufacturing procedures. The need for change in physical and mechanical properties of metals over the last 40 years have resulted in dramatic changes in cladding teclmology necessary to unite dissimilar metals. Cladding processes have departed fran the flat shape of sheet, strip and plate into COtIpOsite bar, wire, tubing, pipe and intricate shapes. Cooposites consisting of powdered metals, fibers, ceramics and non-metallics are now commonplace specifications for clad material. SBIIl'le procedures for bonding or coating have made way to nore exotic procedures involving vaCUl.lll, co-extrusion, explosive bonding and pressure bonding with or without the confines of aorospheric or vaCUl.lll control. Increased demand for clad metals will further stinulate developnent wo:r:k. The continued errosion of the availability of certain strategic rIM materials used for alloying is causing nore attention to coatings and c1addings. A world crisis would spontaneously cause a rapid change to coatings and c1addings as a means of conserving availability of said scarce alloying materials.
(9:00 a.m.)
DEVELOPMENT AND PRACTICAL APPLICATIONS OF CLAD METAL TECHNOLOGY IN THE SOVIET UNION: I. M. Sukonnik, Memory Products Division, The Stolle Corporation, 1501 Michigan Street, Sidney, Ohio 45365 Cl ad metal products fi nd perhaps thei r wi dest appl icat ion in the Soviet Union. Many of these consist of an inexpensive core material which is often ferrous base and claddings of another metal with des i rabl e propert i es such as corros i on res i stance. These latter materials typically include alloys of aluminum, copper, titanium, nickel, or refractory metals. Depending on the particular metals employed and the requi red servi ce characteri st i cs, vari ous techni ques have been developed for clad metal fabri cat i on. These i ncl ude
92 TMS Annual Meeting
processes making use of plastic deformation (at either hot or cold working temperatures), explosive or diffusion bonding, centrifugal cast i ng and e 1ectrodepos it ion. Aspects of the sol id state deformation processes that have been developed and util ized in the Soviet Union will be described. In particular, research into the effects of factors such as surface preparat ion, interface 1ayer sel ect i on, clad-core property differences, layer thi ckness rat io, and deformation rate and temperature on cladding response and subsequent propert i es such as bond strength will be summari zed.
(9:30 a.m.) CLADDING OF METALS BY EXTRUSION: Columbus Division, Columbus, OH
Robert J. Fiorentino,
Battelle
Va ri ous concepts for c 1addi ng soli d and hollow products by extrusion are presented. The coextrusion process is used when the cladding and core materials are close enough in flow-strength characteristics to permit metal flow without introducing necking or fracture of the stronger bi 11 et component. Ca reful select i on of the extrusion parameters is also necessary to avoid unstable metal-flow problems. Coextrusion is typically used to clad the outer surface of solid products or the surfaces of hollow products. A more recent application is the manufacture of multifil ament superconductors and other forms of compos i te . materials. When the flow-strength characteristics of the billet components differ too greatly, the extrusion cladding process is used. In this method, the stronger billet material is not deformed at all; only the softer billet component is extruded. Strong meta 11 urgi cal bonding between components can be achi eved with either extrusion process.
(10:00 a.m.) EXPLOSIVE METAL-CLADDING* N. S. Lalwaney, Battelle, Columbus,OH. Explosive cladding/bonding/welding is a safe, simple, reproducible solid state joining process with a technological versatility to provide a true high-integrity metallurgical bond between both metallurgically compatible and incompatible systems. The process is uniquely suited to bond metals that form intermetallic compounds ate 1eva ted temperatures. The process mechani sm is presented and the parameters that control the explosive-bonding parameters are discussed. Proper control of cladding parameters normally result in wavy bond zone structure whose strength is equal to or greater than the weaker of the two parent metals. Current applications and also the needs of 1990's will be di scussed.
CROSTRUCTURAL CHARACTERIZATION OF ExPLOSIVELY WELDED INTERFACE: Center for Expl os ives Technology "---arch and Metallurgical Engineering, New MeX1CO Institute of ng and Technology, Socorro, New Mexico 87801 osive welding occurs following the achievement of a critical e 8, between the two plates joined, for jetting and the enbond of the two materials. Although previ ous s tructura 1 erizations have indicated the presence of a "bond zone", than a planar interface, they also suggest the presence a three or five layers of distinct structural morphologies. Our analysis to date seems to suggest that explosive welding needs not to involve melting at the interface and the types of microstructural alterations obtained is a direct outcome of the magnitude of the kinetic energy introduced to the weld zone. Welds, that range from a straight configuration to a wavy morphology th extensive vorticity, can be produced by the tailoring of the lding parameters and thus the kinetic energy imparted. In only e latter cases, of excessive kinetic energy input, such structurally different morphologies are obtained; although the hardened "weld zone" is always present and can be delineated by a simple crohardness test.
IV. T. Inal and A. Szecket;
(11 :00 a.m.)
THE CYCLIC PRESSURE DISTRIBUTION AT EXPLOSIVELY WELDED INTERFACE II: A. Szecket, D.J. Vigueras, O.T. Inal, and Ashok Singh; Center for Explosives Technology Research and Metallurgical and Materials Engineering; New Mexico Institute of Mining and Technology, Socorro, New Mexi co 87801 Theoretical predictions on the pulsating nature of the interfacial pressure during explosive welding was substantiated by experimental evidence. Several experiments were undertaken utilizing aluminum to steel welds, with and without an intermediate nickel depOSit, on the steel base plate. In the initial experiments, an aluminum flyer plate was bonded to a mild steel base plate with the weld exhibiting a straight interface and no discernible formation of Fe-Al intermetallics. The formation of the Fe-Al intermetall ics were then indu~ed through anneals of the weld at 550 C for periods of 8, 10 and 12 h followed by metallographic and Illicrohardness characterizations. The second phase of the experiment consisted of electrodeposition of a thin layer of nickel onto mild steel base plate previous to the explosive joining. The cyclic distribution of the pockets of nickel in the straight (waveless) Fe-Al interface observed in the welds is taken as a further verifi cati on of the pul sati ng nature of the interfacial pressure.
HIGH RESOLUTION TEM STUDIES OF ELECTRONIC MATERIALS I:
Sponsored by the TEM Chemistry and Physics of Metals Committee Wednesday, March 5, 1986
Bacchus
8:30a.m. Marriott Hotel Session Chairmen: K. H. Westmacott, Lawrence Berkeley Laboratory, University of California, Berkeley, CA 94720; S. M. Ohr, Solid State Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
(8:30 a.m.) HIGH RESOLUTION TEM OF SEMICONDUCTOR INTERFACES: Robert Sinclair, Dept. of Materials Science and Etlg'ineerinq, Stanford University, stanford, California 94305.
During the manufacture of semiconductor devices, a complex sequence of processin:;)' steps is carried out. The resultant material has several different compounds in intimate contact with one another. The electrical characteristics of the device are influenced to a great extent by the nature of the interfaces present. Microstructural characterization is best performed by examining the device in cross-section, and since important features are generally on an extremely small scale (=nm) high resolution electron microscopy is essential for revealing pertinent details of the structure. A review will be given of our work over the last five years in this field, emphasizing the relationship between minute microstructural parameters with device processiI'g' and electrical characteristics. Examples will be drawn from studies of silicon and compound semiconductors. In addition, a movie will be shown of solid-phase epitaxial regrowth of silicon, taken at lattice resolution at 720°C.
(9:00 a.m.) HIGH RESOLUTION ELECTRON MICROSCOPY OF SEMICONDUCTOR INTERFACES AND SURFACES: J. M. Gibson, AT&T Bell Laboratories, Murray Hill,
NJ 07974 Interfaces between epitaxial thin metal, insulator and semiconductor films have been studied with high resolution electron microscopy. Atomic structure is related to novel Schottky barrier behavior and interface electronic transport. In-situ studies of semiconductor surfaces and the initial stages of epitaxy were performed in a modified ultra-high vacuum high resolution microscope. In-situ studies illuminate the growth processes of molecular beam epitaxy.
(9:30 a.m.) ELECTRON MICROSCOPY OF REACTION PRODUCTS AT METAL/GALLIUM ARSENIDE INTERFACES: T. Sands, Bell Conrnunications Research, Inc., 600 Mountain Avenue, Murray Hill, NJ 07974 and Center for Advanced Materi a 1s, Lawrence Berkel ey Laboratory, Berkel ey, CA 94720. The formation of reaction products at a metal/compound semiconductor interface may alter the electrical properties of a contact by virtue of the morphology of the reaction front, the inherent electrical properties of the new phases(s) or the reaction-induced nonstoichiometry of the semiconductor near the interface. Understanding these chemical and structural changes requires characterization of metal/compound semi conductor interfaces on the nea r-atomi c scale. In thi s presentation, recent application of high resolution imaging and microanalysis to stUdies of metal (eg. Ni ,Pd, Pt and In)/GaAs reactions will be described. Results such as the identification of new ternary phases (ed. Pd4GaAs and Pd5(GaAs)2) and the determination of the effects of native oxides on film uniformity contribute to the development of improved reacted contacts for device applications.
(10:00 a.m.) HIGH RESOLUTION STUDIES OF EXTENDED DEFECTS AND INTERFACES IN GaAs AND RELATED COMPOUNDS: B. C. De Cooman, C. B. Carter, N.-H. Cho, J. R. Conner, Department of Materials Science and Engineering. Bard Hall, Cornell University, Ithaca, NY 14853. The presentation will highlight the different aspects of HREM of III-V compounds at Cornell. With the development of high-voltage high-resolution electron microscopes, it is now possible to obtain structure images of defects in the small lattice parameter crystals which are commonly used in opto-electronics. The topics which will be addressed in the talk will be: (1) HREM of end-on dislocations in high-stress deformed GaAs, (2) the structure of interfaces in a variety of strained and unstrained superlattices, (3) the structure of facetted APB in GaAs, (4)
ion-implantation in super1attices. In recent publications several authors have claimed that atomic resolution could be achi eved. However, a ri facts due to surface stra in re 1 axati on in the thin foil and the precise imaging conditions can severely alter the image contrast. Due to the impact of TEM microanalysis on the materials development in microelectronics these effects are being carefully studied.
(10:30 ATOMIC Smith, Tempe,
a.m.l IMAGING OF DEFECTS AND SURFACES IN SEMICONDUCTORS: D. J. Center of Solid State Science, Arizona State University, Arizona 85287.
Latest developments in i ntermedi ate voltage (300-400 KV 1 HREMs enable atomic resolution images of defects and surfaces to be obtained. Recent app1 ications of the ASU 4000 EX will be discussed.
HYDROMET ALLURGICAL REACTOR DESIGN & KINETICS V Sponsored by the TMS-AIME Hydrometa/lurgy, Physical Chemistry, and Electrolytic Processes, and SME-AIME Chemical Processing Committees Wednesday, March 5,1986 La Galerie 6 8:30 a.m. Marriott Hotel Session Chairpersons: Fiona M. Doyle-Garner, Department of Materials Science and Mineral Engineering, University of California, Berkeley, CA 94720; Victor A. Ettel, J. Roy Gordon Research Laboratory, INCO LTD., Mississauga, Ontario, UK IZ9, Canada
(8:30 a.m.) RATE PROCESSES IN SOLVENT EXTRACTION: MODEL EXPERIMENTS USING A TWO-DIMENSIONAL ORGANIC PHASE: D. J. Chaiko and K. Osseo-Asare, Mineral Processing and Metallurgy Programs, The Pennsylvania State University, University Park, PA 16802 Current theories of metal extraction suppose that the ratelimiting complexation reactions OCCur either directly at the organic/aqueous interface or within a narrow zone on the aqueous side of the interface. There is therefore a need to develop experimental techniques that can be used to investigate the aqueous interfacial region. The Langmuir film balance, which uses a monomolecular organic film spread on an aqueous subphase J permits one to control the concentration as well as the orientation of the adsorbed molecules of a surface-active reagent. The rate of desorption of the chelating reagent 2-hydroxy-5-alkylbenzophenone oxime (LIX65N) into the aqueous phase has been investigated by measuring the change in film area with time while maintaining a constant film pressure. The relevance of the film desorption results to metal extraction rates is discussed.
(9:00 a.m.) THE EFFECTS OF DISPERSED PHASE MIXING ON EXTRACTION OF METALS: L. L. Tavlarides, Syracuse Univ., Syracuse, NY 13210, J. H. Bae, Syracuse Univ., Syracuse, NY 13210
TMS Annual Meeting 93 leach solution. The process provides significant economic benefits over the Merrill-Crowe process. The next generation of gold recovery processes Is likely to include con tinuous fluidized bed type adsorption process and a more economic desorption process. Such a system using ion exchange resins to recover elements such as uranium is well developed in the mineral industry. However, such multi-stage systems have complicated internals and control sys terns to regula te resin movements. In comparison s ingle-s tage deep fluidized systems have the attraction of relatively simple engineering and have been proposed for the recovery of metals from solution. The present paper will discuss the development of a flowsheet based upon test results obtained in comparing carbon and ion exchange resins for gold removal. The paper will also discuss electro elution of gold from loaded carbon.
(1 J:08 't.".)
3:C,K
(10:30 a.m.) SIMULATION AND CONTROL OF A THREE STAGE LIQUID-LIQUID EXTRACTION UNIT: C. P. Jeffreson, Department of Chemical & Metallurgical Engineering, Mackay School of Mines, University of Nevada Reno, Reno, NV 89557 The dynamiCS, simulation and control of a three stage mixer settler system for the extraction of copper from an aqueous solution using LIX-64N reagent in kerosene is considered. From the control viewpoint, the objective is to achieve a specified final copper concentration in the aqueous phase subject to variations in demand for product and in the concentration of the feed. Manipulated variable in this work was the feed rate of LIX reagent. Simulations were performed to predict the controller settings required for feedback control using a simple model ·which assumed perfect mixing in the mixers and plug flow of the organic phase in each se ttler. The aqueous phase in each settler was assumed to be perfectly mixed. This simple model was found to predict the experimental controller settings to sufficient accuracy for control purposes provided that a simple feed forward control strategy to allow for flowrate changes of the aqueous phase was added.
(11:00 a.m.) TRANSPORT OF PLATINUM (IV) THROUGH SUPPORTED LIQUID MEMBRANE CONTAINIIIG TRIOCTYLAMINE CARRIER: Tadaaki Nishiki and Renato G. Bautista, Ames Laboratory, USDOE and Department of Chemical Engineering, Iowa State University, Ames, Iowa 50011. *Now at Chemical &: Metallurgical Engineering Department, University of Nevada Reno, Reno, NV 89557 The permeation and concentration of very dilute solution of platinum through a supported liquid membrane is presented. The permea tion expe rimen ts were ca rrled ou t us ing a Tef Ion fil ter membrane impregna ted wi th xylene solution of trioc tylamine as a mobile carrier to investigate the effects of a number of parameters on the permeation rates. Platinum was transported and concentrated from the RCI solution to the Na C0 or NaOR solution 2 3 across the liquid membrane. A high concentratIon factor of platinum was obtained. The effects of the concentration of TOA carrier and that of platinum in the feed and stripping solutions on the permea tion ra te of platinum are discussed. The experimental results are compared with a simple permeation model to clarify the permeation mechanism of pIa tinum through the membrane.
A fundamental study is in progress to determine the effects of
dispersed phase mixing on the solvent extraction of metals. Dispersed phase mixing in a well characterized continuous flow stirred cell will be compared to r~sults from our simulation model. The system under investigation is Co(II)-acetate buffer/ D2EHPA-to1uene. The kinetic rate law and the thermodynamic equilibrium constant are being determined in our laboratories. The stirred cell is equipped with a capillary laser-spectrophotometer detector system to measure bivariate drop size distribution data. The technique is an adaptation from Verhoff et al. (1977), Janjua (1982) and Goldman et al. (1984). Dispersed phase hold-up is also measured simultaneously with an ultrasonic technique developed in our laboratories. The interval of quiescence simulation technique is employed to analyze the data and assess the effect of physico-chemical and operational parameters on the droplet mixing frequency and the concommitant result on interphase mass transfer.
(9:30 a.m.) A COMPARATIVE STUDY ON TIlE RECOVERY OF GOLD BY ION EXCHANGE AND ACTIVATED CARBON: V. I. Lakshmanan, Ontario Research Foundation, Mississauga, Ontario L5K IB3; CANADA and G. M. Ritcey, CANMET, 555 Booth Street, Ottawa Ontario KIA OGI CANADA Carbon-In-Pulp (CIP) process is now widely applied in the major gold producing countries for the recovery of gold from pregnant
(11: 30 a.m.) THE COPRECIPITATION KINETICS OF Co(H) and Ni(H) with Al(III) AND Fe(II!) IN AMMONIACAL SOLUTIONS: K. H. Han and II. Ahmad, Department of Metallurgical Engineering, South Dakota School of Mines and Technology, Rapid City, SD 55701 Previous studies showed tha t cabal t can be precipitated preferentially in the presence of nickel with Al( HI), Crt II I), Fe (II I) and Mn(IV) in ammoniacal solutions, leaving nickel in solution. The emphasis in this study is on the kinetics of the preCipitation of cobalt and nickel, together with Al(III) and Fe(III) to delineate the mechanism of the coprecipitation process and to assist in designing the optimum operation for the slective removal of cobalt from nickel in real reactor systems. The kinetics of the coprecipitation has been studied as a function of temperature, pH of the solution, the ratio of Co/Ni in the solution and oxygen potentIal of the system. The resul ts up to date indicate that the initial rate of precipitation of Fe(III), Mn(IV) and Al(III) in ammoniacal solutions is much faster than that of nickel, while that of cobalt is frequently as fast as the trivalent ions which makes the selective removal of cobalt from nickel possible.
94 TMS Annual Meeting
INTERFACES IN COMPOSITES II: Characterization Sponsored by the TMS-ASM Composite Committee Wednesday, March 5,1986 Mardi Gras A-B Marriott Hotel 8:30a.m. Session Chairmen: Dr. Irwin G. Greenfield, Department of Mechanical & Aerospace Engineering, University of Delaware, Newark, DE 19716; and Dr. Steven G. Fishman, Office of Naval Research, Arlington, VA 22217
2124 Al, or 6061 Al reinforced with graphite, boron or SiC) have been analyzed to determine the concentratlon of dislocations that were mobile during low strain (<10- ) ultrasonic tests. The apparatus used was the PUCOT (piezoelectric ultrasonic composite oscillator technique) at room temperature and 80 kHz. Two approaches to the analyses are considered: the Granoto-Luecke (G-L) theory of dislocation dampin9 for 0 K (GLOK), and the G-L theory for high temperatures (GLHT). As an exam~le of the analyses, ~he GLOK theop yi~lds dislocation d~ns't,es ,n the range 1~2 to 10 10 cm- , wh,le the GLHT theory glVes values near 10 cm . These determinations are discussed in rela£ion to the TEM observations of dislocation densities of 10 10cm- found in 6061 Al-SiC by Arsenault and Fisher.
(ll : 00 a. m. ) (8:30 a.m.) THE ASSESSMENT OF INTERFACIAL ADHESION IN FIBROUS COMPOSITES: B. Z. Jao&, L. R. Hwang. and Y. K. Lieu. Dept. of Mech. Eng.,
Auburn University, AL 36849.
The experience of using several popular techniques for measuring the interfacial adhesion between the fiber and matrix will be presented. After a critical review on the conventional methods several modified versions of the old techniques and a few new ODes will be presented and discussed; the latter including the acoustic emission-assisted technique~ the push-out method. and the dynamic mechanical thermal analysis. Also to be discussed are the effects of plasma treatment on the interfacial bonding between fibers and polymer matrices (both thermoset and thermoplastics).
RESIDUAL STRESSES IN METAL MATRIX COMPOSITES: Y.M. Cheong and H.L. Marcus, Department of Mechanical Engineering, Center for Materials Science and Engineering, The University of Texas, Austin, TX 78712 <
Interfaces between components wi th different coeffi ci ents of thermal expansion lead to high residual stresses in the metal matrix composite. The measurement of these stresses is experimentally difficult. This paper will describe two approaches used to measure the residual stresses. The first is using x-ray diffraction to measure the strains and the second is the use of Raman spectroscopy following 1ine shape and line shifts in the spectrum. Experimental results from both approaches will be gi ven and the problems in both approaches di scussed. This research was NOOOl4-84-K-0687.
supported
by
DARPA
under
contract
ONR
(9: 00 a.m.)
INTERFACE STRUCTURE IN SILICON CARBIDE-SILICON NITRIDE COMPOSITES; S.R. Nutt, Center for Solid State Science, Arizona State University, Tempe, AZ 85287. High resolution TEM techniques have been used to investigate the atomistic structure of interfaces in SiC whisker reinforced Si3N~. SiC whiskers used in composites were grown by a VLS process and exhibited rounded triangular cross-sections. High resolution images from composite specimens revealed that the whisker interface plane, ostenSibly (lIO}, was in comprised of microscopic steps and ledges on planes, forming a sawtooth profile. The notches by the steps constitute strength-limiting cts in the whiskers and increase the frictional e required for whisker pull-out during composite ture. There was no evidence of interfacial glassy , implying a strong interface bond. Epitaxial phase particles were normally present where 4 grain boundaries intersected the SiC interface. 1cations of interface structure with respect to ite fracture behavior will be discussed.
OF MICROSTRUCTURE OF METAL-MATRIX COMPOSITES TO SOLIME: M.N. Gungor, J.A. Cornie and M.C. Flemings, ssachu<;etts Institute of Technology, Cambridge, MA 02139. Materials Processing Center. In the pressure casting process, the solidification time controls the microstructure of metal-matrix composites. In the Al-4.S%Cu model matrix system reinforced with 40v/o fiber F.P. alumina the distribution of Cu in the matrix is directly related to solidification kinetics. When the alloy is solidified at relatively slow rates, the average Cu content of the matrix was higher. Thus, the amount of non-equilibrium A12Cu second phase was reduced. The Al2Cu phase was precipitated primarily at the fiber/matrix interface. The microstructure was altered significantly when solidification rate was increased. In this case, the matrix was depleted in Cu which resulted in an increase in A12Cu precipitation. A12Cu was distributed throughout the matrix as well as at the fiber/matrix interface. In this paper, the leading mechanisms are discussed and the engineering importance of this phenomena is explored. Mechanical properties are related to solidification processing and fracture surfaces are characterized.
(10:00 a.m.)
BREAK
(10:30 a.m.) DISLOCATION DENSITY DETERMINATIONS IN COMPOSITES USING THE PUCOT J. T. Hartman, Jr., K. H. Keene, R. J. Armstrong and A. Wolfenden, Mechani cal Engi neeri ng Department, Texas A&M University, College Station, Texas 77843. Measurements of the strain amplitude dependence of internal friction for several metal matrix composites (1100 Al, 2024 AI,
LEAD, ZINC AND TIN II: COPING WITH THE TIMES: Cost, Productivity and Technology Improvements Sponsored by the TMS Lead, Zinc, Tin Committee Wednesday, March 5,1986 La Galeria 2 Marriott Hotel 8:30 a.m. Session Chairmen: J. E. Hoffman, Exxon Minerals Co., 5630 Guhn Road, Houston, TX 77040; N. E. Ghatas, Noranda Research Centre, 240 Hymus Blvd., Pointe Claire, Quebec H9R 105
(8:30 a.m.) MODIFICATIONS TO THE RUHR-ZINK-SMELTER IN DATTELIN: Dr. Adolf von Ropenack, C.E.O., RUHR-ZINK GMBH, Wittener Str. 1, 4345 Dattelin After installation and commissioning of a fully integrated hematite process in the electrolytic zinc plant of RuhrZink ClnbH in Dattein in 1979 - making the plant the first electrolytic zinc plant in the world without any waste products - some further interesting modifications have been made. A simplified flowsheet indicates the process-steps of the operation (Figure I). The modifications concern the environmental protection in the leaching and leach-purification plant, improved safety in the working environment of the roasting plant, economic optimi sation of the waste gas cleaning system in the melting plant as well as the development of a new anode for the electrolytic process in the tankhouse.
(9:00 a.m.)
WET ZINC DUST ATOMIZATION AND DISTRIBUTION AT CANADIAN ELECTROLYTIC ZINC: J. P. St-Onge, J. Leroux, Canadian Electrolytic Zinc Limited, Valleyfield, Quebec. The world's first water-atomized zinc dust production unit was commissioned at Canadian Electrolytic zinc in valleyfield in 1985. The system consists of an atomizing unit, a dewatering, storage and retrieval system, and an automated make-up distribution loop. In order to maintain the plant water balance, atomization water is recovered, filtered and reused, while purified zinc sulphate solution is used for slurrying of tho zinc dust and distribution to the purification circuit. In addition to the obvious advantage of eliminating a dusting problem, a reduction in zinc dust consumption in the order of 33% is anticipated. This greater efficiency is attributed to the smaller mean particle size of the liquid atomized zinc dust and irregular shape of the particles which results in about twice the surface area for specific particle size. This
reduction in zinc dust consumption will result in more zinc available for sale or in reduced electrolysis operating costs depending upon market conditions. (9:30 a.m.) OPTIMISATION OF THE LEAD-SINTERPLANT AND BLAST-FURNACE-OPERATIONS AT METALLURGI E HOBOKEN-OVERPELT: I r .Antoon Franckaerts, Deputy Plant Manager, Hoboken Plant, Metallurgie Hoboken-Overpelt, L710 Hoboken, Belgium. Despite the 10n'1 ten" prnpr to the contimlou<;ly ch"n;~ini' nceel" to rroce«., ",ore co,,"'l,,'< l'at(>rl:115 Clod to (or.pl" 10/1 th striett-r environrwntill reC>1I1dt Inns. In the "inter ~lornrenenus
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THE DEVELOPMENT OF MICROSTRUCTURE AND CHARACTERISATION OF PHASES INS I LI CON-ALUfll NUM BRONZE AND COPPER-MANGAN ESE-ALUM INUM: G.W. Lorimer, J. Iqbal and F. Hasan, University of Manchester/ UMIST, Department of Metallurgy and Materials Science, Grosvenor Street, Manchester M1 7HS, U.K. The microstructural development and the morphology, crystallography and the composition of the phases present in as-cast silicon-aluminum bronze (SAB) of nominal composition Cu-6wt:;A1 -2wt%Si-0.6wt%Fe and a copper-manganese-a1uminum (CMA) alloy of nomi na 1 compos iti on Cu-14wt%Mn-Bwt%A 1-3wt%Fe-2wt%Ni have been investigated using optical, electron optical and microprobe analysis techniques. The as-cast microstructure of the SAB consisted of " and v-grains containing two types of intermetallics: 1arge irregularly-shaped particles (Fe sSi 3 ) , sparsely distributed in both types of grains and a high density of small lath-shaped precipitates (Fe 3 Si,) with a B2 structure. The as-cast microstructure of CMA consisted of " and B phases containing intennetallic precipitates of various morphologies that are rich in i ron and manganese.
th",
(10:00 a.m.) ENERGY COST REDUCTION AT BRUNSWICK SMELTING:
TMS Annual Meeting 95
(2:25 p.m.)
M. D. Street
An cncrg'Y mlUlagcmcnt programme was instituted in 1981 at the Lead Smelter facility of Bruru;voick Mining and Smalting Corporation Limited, BeUedune. New Brunswick. FoUowing an initial energy 8udH which tdentifi@d areas of hii{h conswnption and cost. the programme ",as continuod In order to reduce these costs. Design and process changes are d.Jscusscd. which have resulted in energy sevin8"R of 51 Million per annum.
(10:30 a.m.) PROCESSING TECHNOLOGY, ECONOMICS: E. Nomura, H. Kubo, K. Kikuta, MItSUI MInIng and Smelting Co.Ltd., 2-Chome, Nihonbashi-Muromachi, Chuo-Ku Tokyo, Japan. Mitsui Mining and Smelting Co., Ltd. has two zinc smelters, Kamioka and Hikoshima, and or-her two, Miike and Hachinohe, which belong to its subsidiaries. They consist of two electrolysis. one ISP and one vertical retort process and their total zinc production was 225,000 t/y in 1984. In the falling zinc market folloWing the first oil crisis in 1973, they have been making efforts to keep and strengthen their economical competitiveness according to their situation. For example, zinc alloys. zinc powder, and zinc chemicals are produced. which add to the value of zinc. Heat recovery and on-site power generation are developed. Instead of zinc concentrates, cheap raw materials like steel dusts and zinc drosses are fed to vert Leal retort processes.
(2:50p.m.) PRECIPITATION IN COPPER-RICH Cu-Cr ALLOYS: J.B. Posthill, U. Dahmen and K.H. Westmacott, National Center for Electron Microscopy, Materials and fl01ecu1ar Research Division, Lawrence Berkeley Laboratory, University of California, Berkeley, CA. Previous results concerned with Cr precipitate morphology and orientation relationship with the Cu matrix appear to be conflicting. One study has found a variety of morphologies (lath and otherwise) with a range of orientation relationships between K-S and N-W whereas another study has observed only needle-like Cr precipitates in a similar alloy with the K-S orientation relationship exclusively. These investigations in conjuncti on with the present experimental results wi 11 be rationalized in terms of the respective heat treatment cycles used. Transmission electron microscopy results from the interfaces of we ll-characteri zed preci pitates wi 11 be presented. The invariant line hypothesis for f.c.c.-b.c.c alloy systems will be used to explain the observed morphologies. Thi s work is supported by the Di rector, Offi ce of Energy Research, Office of Basic Energy Sciences, Materials Sciences 8~~it3~~76gfoo6S§. u. S. Dept. of Energy under Contract No.
(3:15 p.m.)
Break
(3 :30 p.m.) DEVELOPMENT OF IN SITU PREPARED Cu BASE COMPOSITE ALLOYS':
PHASE TRANSFORMA nONS IN COPPER ALLOYS II: Effect of Phase Transformations on Structure and Properties Sponsored by the TMS Non-Ferrous Metals Committee and TMS/ ASM-MSD Phase Transformations Committee Wednesday, March 5,1986 Mardi Gras I-J 8:30 a.m. Marriott Hotel Session Chairmen: R. 1. Livak, Materials Science & Technology Div., Los Alamos National Laboratory, Los Alamos, NM 87545; A./ Guha, Brush Wellman Inc., 17876 St. Clair Avenue, Cleveland, OH 44110
J. D.
Verhoeven, F. A. Schmidt and E. D. Gibson, Ames Laboratory Iowa State UniverSity, Ames, IA 50011. In work initiated to develop Nb 3Sn-Cu composite 8uperconducting wire a new technique, termed the in situ process, has evolved which produces high strength Cu--Nb alloys. The process generally involves two steps, solidification followed by severe mechanical reduction. The solidification step produces Nb dendrite arrays in a nearly pure Cu matrix and the mechanical reduction step produces alignment of the dendrite arms in the drawing or rolling direction. The technique is applicable to several binary Cu-X alloys which possess phase equilibria similar to Cu-Nb. We review here work on developnent of consumable arc melting techniques aimed at scaling up the process to 6 inch (15 cm) diameter ingots for alloys of Cu-Nb, Cu-Cr, Cu-V, Cu-Ta, and Cu-Fe. typical phYSical property data will also be presented on strength, electrical conductivity, thermal conductivity, plus the heat transfer characteristics of etched surfaces of Cu-Nb alloys.
*This work was supported by Director of Energy Research, Office of Basic Energy Sciences, USOOE.
(2:00 p.m.) PHASE RELATIONSHIPS AND PHASE TRANSFORMATIONS IN SELECTED ALUMINUM BRONZES: G.W. Lorimer, Y.S. Sun, F. Hasan, J. Iqbal and N. Ridley, University of Manchester/UMIST, Department of Metallurgy and Materials Science, Grosvenor Street, Manchester M1 7HS, U.K. The morphology, crystallography, and chemistry of phases present in as-cast copper-aluminum alloys containing additions of iron and nickel, and the development of microstructure on cooling from elevated temperatures, have been studied using optical and electron optical technioues. The microstructure of as-cast copper alloys containing 9 to 10 wt% A1 consists of fcc" phase, an eutectoid decomposition ~roduct of u and V2 and martensitic S' with the 3R structure. 'rn alloys containing 9 wt% A1 and 3 to 5 wt% nickel the eutectoid decomposition temperature was ra i sed and the trans forma t i on product was (X and 62 (Ni A1 ) . Additions of 2.5 wt% iron to Cu-10wt%A1 produced an as-cast microstructure consisting of fcc (X-phase, a martensitic phase with the 9R crystal structure, and iron-rich intermetallic preci pi tates based on Fe JA 1.
(3:55p.m.) TRANSITIONS IN EUTECTOID MICROSTRUCTURE IN COPPER ALLOYS CONTAINING 11 WT.% AL TO 13 WT.% AL: R. J. Farrell and A. Hellawell, Dept. of Metallurgical Engineering, Michigan Technological Uni versi ty, Houghton, MI 49931 The eutectoid microstructure, S + ct + Y2 has been examined in the presence of variable dispersions of pro-eutectoid Y2 phase by isothermal heat treatments in the temperature range 450°C to 570°C. It is observed that the fine structure of the eutectoid is very sensitive to the volume fraction and separation of the primary phase and there occurs a lamellar to globular transition in a narrow temperature range from l:::IS20°C to l:::I 530°C; this transition temperature is also composition dependent. The transition appears to occur when the spacing between the primary phase approaches that of the interlamellar diffusion distance and is comparable with structures in malleable cast irons and eutectic alloys.
96 TMS Annual Meeting (4:20 p.m.) NEW DEVELOPMENT IN COPPER-ZIRCONIUM BASE ALLOYS: C. T. Burnham, F. Gruss, V. J. MarIno. P. W. Taubenblat. United States Metals RefIning Co.; Research &. Development Dept.; Carteret, New Jersey 07008 High-st rength, hIgh-conduct 1 v i t Y copper-zirconium alloys are used in a varIety of electrical and electronic applications. To achieve optImum properties, the zirconium level must be controlled. The processIng parameters, which include hot raIling, solution annealIng, aging and cold working, need to be carefully set to attain proper metallurgical structures and a combination of best mechanical and electr lcal properties. ThIS paper reVIews the casting/extrusion/cold working and heat treatIng conditions of copper-zIrconium alloys and discusses physlcal and mechanical properties at cryogenic, room and elevated temperatures. Latest applications in the electrical, electronic, weldlng and thermal conductivity flelds are also reviewed.
PHYSICAL CHEMISTRY III: APPLIED THERMODYNAMICS OF EXTRACTIVE PROCESSES Sponsored by the TMS Physical Chemistry Committee and the ISS/PTD Mardi GrasN Wednesday, March 5,1986 Marriott Hotel 8:30a.m. Session Chairmen: D. M. Kundrat, Armco Research and Technology, Middletown, OH 45043; and C. A. Natalie. Department of Metallurgical Engineering, Colorado School of Mines, Golden, CO 80401
meter. These measurements were conducted on a typical lead b1astfurnace slag, and this master slag doped with various amounts of Si02. A1203, CaO, MgO, and/or ZnO. It was found that additions of A1203 and/or Si02 increased the viscosity of the master slag over the enti re temperature range of interest (1150 0 -1350°C). Additions of the basic oxides (CaO, MgO. and/or ZnO) decreased viscosity at high temperatures, but raised the temperature at which the slag viscosity sharply increased. The viscosity data of this study, along with that of several simi1-ar studies in the 1 i tera ture, were corre 1a ted wi th a compos it ion-dependent funct ion. PbO and ZnO activity coefficient data from the 1 iterature were a 1 so co 11 ected and corre 1 a ted with compos it ion-dependent funct ions
(9:45 a.m.) PbO SOLUBILITY IN LEAD BLAST-FURNACE SLAGS: M. E. Schlesinger and D. C. Lynch, Department of Materials Science and Engineering, University of Arizona, Tucson, AZ 85721.
The solubility of lead oxide in CaO-Si0:i-FeO-Fe203 slags in contact with molten Pb and Pb-Ag alloys at 1473 K have been investigated at conditions similar to lead blast furnace operations. The solubility of PbO in the slag has been related to the slag's ferric/ferrous ion ratio. The influence of the CaO/Si02 and Fe/Si02 ratios on the solubility have also been investigated. The results are compared to that obtained in other studies conducted at higher partial pressures of 02 and at silica saturation.
(10: 10a.m.) EQUILIBRIUM BETWEEN SULFUR AND TlTANllJM IN LIQUID IRON: r. M. Donahue and R. D. Pehlke, Department of Materials and Metallurgical Engineering, University of Michigan, Ann Arbor,
Ml' 48109
(8:30 a.m.) THE USE OF O?-ENRICHED AIR IN THE SELECTIVE SULFATION ROASTING OF CHALCOPYRITE. ~ and J.P. Hager, Colorado School of Mines. Golden. CO. An experimental study was undertaken to examine the feasi·· lity of using oxygen-enriched air in the selective sulfation sting of chalcopyrite in a fluid bed reactor. A thermodynamic lysis showed that the use of oxygen-enriched air should retard the formation of copper ferrite and allow roasting to be conducted at a somewhat higher temperature, which should improve the reaction kinetics. Experiments were conducted in a 6-inch I.D. fluidbed reactor running under steady state conditions. An analysis the reaction products showed that an operating window does ist where CuS04 and Fe203 are the stable phases. It was 'ned that copper ferrite did not form until its activity a value of 1.4, thus allowing for a higher operating rature than predicted. The maximum concentration of oxygen n the fluidizing gas was determined to be 60%.
LITY AND FORM OF Bi IN COPPER METALLURGICAL SLAG AND TIlE INFLUCaO ANDA1203 ADDITIVES: S.C. Marschman, Battelle Pacific st Laboratory, Richland, WA; and D.C. Lynch, Department of MaIs Science and Engineering, University of Arizona, Tucson. AZ.
solubility of Bi in silica-saturated iron silicate slags has been at constant activities of Bi, at temperatures of 1458 and 523 K, and at partial pressures of oxygen ranging from 10- 12 to 10- 8 atm., Bismuth has been found to exist in slag in both a neutral form and as BiD. The solubility of Bi in slag can be represented by the following equation: NBi ::: PBi/YBi + (PBiK/YBiO)PO/~ where NBi is the total mole fraction of Bi in the slag and K is the equilibrium constant for the reaction: Bi(g) + ¥Jz = BiO(l), inK = -23.2 + 72600/T. The activity coefficient for neutral Bi, YBi, has been found to have a value of 1.1.10 3 and to be essentially independent of temperature. Values for rBiO were found to decrease from1.l0 8 at l458K to 7 .10 6 at 1523K. The influence of CaO and A1 2 03 additions on the solubility of Bi was examined at a fixed Fe 2+/Fe 3+ ratio. The additions were found to have only a slight effect. ~stigated
(9:20 a.m.) VISCOSITIES AND ACTIVITIES OF LEAD-SMELTING SLAGS: T.P. Battle, University of Michi9,iln. Ann Arbor, MI and J.P. Hager. Colorado School of Mines, Gol":len, CO. In the development of new lead smelting processes it is crucial that quantitative data be available to predict the variation in slag viscosity during slag cleaning. Data is also required on the variation of lead oxide and zinc oxide activities with temperature and slag composition. Viscosity measurements at high temperature were made using a concentric cylinder visco-
This investigation of the Fe-Ti-S system has invol ved experimental measurements of the titanium sulfide solubility product in liquid iron over the temperature range l560°C to l640°C. Titanium contents were varied from 1 to 5 weight pel·cent. Using literature values for the titanium and sulfur selfinteraction parameters, the activity coeffic.ients for titanium and sulfur and the interaction parameter, eS1., have bee!l defined. The titanium-sulfur interaction parameter, es 1 , was determined to be -0.20 at l600°C. The temperature dependence of e was found to be very small J varying less than 10% over the temperature range l560°C to l640°C. Comparisons with the Fe-Zr-S system are presented.
1i
(10:35 a.m.)
MODELING OF SULFIDE CAPACITIES OF SILICATE MELTS' R. G. Reddy! and M. Blander, Chemical Technology Division, Argonne National Laboratory, Argonne, IL 6043Q We have calculated sulfide capacities,
c.[= (~y/2 wt%s]' thermody-
namically using fundamentals solution concepts. The results agree very well with published experimental data. The results indicate that there is no direct relation between sulfide exchange equilibrium constants and the basicity of slags. The general correlation in current use between these constants and basicity cannot be generally valid.
'This work was supported by the Division of Materials Sciences, Office of Basic Energy Sciences of the U. S. Department of Energy. !Permancnt address Department of Chemical and Metallurgical Engineering, University of Nevada-Reno, Reno, Nevada 8Q557.
(11 : 00 a. m. ) COBALT OXIDE R. G. Reddy, Engineering, Reno, Nevada
ACTIVITY IN IRON-SILICATE SLAGS. P. Sahoo and Department of Chemical and Metallurgical Mackay School of Mines, University of Nevada-Reno, 89557
Cobalt oxide activity in CoO-FeO-Fe01.5-AI0l.S-Si02 slag was determined by equilibrating the slag with gold-cobalt alloy at 1573 K and Fe/Si02 ratio 1.31. Oxygen partial pressure between 10- 8 to 10- 10 atm was maintained over the slag melt using CO/C02 gas mixtures. For the experimental range of 0 to 10 percent cobalt in slag studied, the activity coefficient of cobalt oxide and distribution coefficient of cobalt were determined to be 0.98 and 91.4, respectively. Cobalt losses in slag predicted from the present investigation are in agreement with that of actual losses observed in the industrial smelting slags.
(11 :25 a.m.) EQUIBRATION OF HYDROGEN CYANIDE GAS WITH PRECIOUS METALS LEACH SOLUTIONS: J.E. Pahlman, D.N. Tallman, and S.E. Khalafalla, Bureau of Mines, Minneapolis, MN Alkaline cyanide solutions are employed in leaching of gold and silver from their ores. At high pH the concentration of molecular HCN in equilibrium with leach solutions is infinitesimally small, however sudden excursions in pH to acidic valu~s will result in liberation of toxic HCN gas, a health hazard for operating personnel. One such excursion occurs in the cleaning of scaled "State of Maine" filters which are frequently used to remove suspended solids or collect precipitated precious metals. As part of its mission to evaluate safe and reliable methods to perform mining and mineral operations, the Bureau of ~1ines is determining the cyanide speciation (HCN gas, HCN in solution and CN-ions in solution) as a function of solution pH and degree of complexation of cyanide with zinc, copper, silver and gold.
PROCESS MINERALOGY APPLICATIONS TO MET ALLURGICAL PRODUCTS AND REFRACTORIES Sponsored by the TMS-SME Process Mineralogy Committee, Wednesday, March 5,1986 La Galerie 3 8:30 a.m. Marriott Hotel Session Chairmen: Daniel C. McLean, 18388 Jesus Maria Road, Mokelumne Hill, CA 95245; James A. Soles, CANMET, 405 Rochester St., Ottawa, Ontario KIA OGI
(10:00 a.m.)
TMS Annual Meeting 97
THE PROCESS MlNERAI..OSY STUDY OF REDUcrICN OF TITANCl'1AGNEJ'ITE WITH
CA.'UDN: H.C.Hsiao and Z.L.Yang, Institute of Chemical Metdllurgy, Acauemia Sinica, Beijing, China
The carton reducing process of titanorragnetite (an intergrowth of magneti te and ul vospinel) has studied by using optical microscope and scanning electron microscope equipped with an energy dispersive X-ray spectraneter. The block samples of intergrowth were reduced by carbon at temperatures ranging from BOOoe to 1200 o e. The fornation of metallic iron CO!TiTlences at about 1000 o e. Owing to the fact that ulvospinel dissolves into magnetite at tem~ra tures lower than 1000 0 e but coalesces at tem~ratures higher than 1000°C, the reducing mechanism changes at different temperatures. At 1200 o e, coalescence of ulvospinel and reduction of magnetite occur simultaneously. Ulvospinel is first reduced to ilmenite and then to anosovite solid solution. The ilmenite to be an intenne.diate reactant of necessary in titanomagnetite reduction, plays an important part in controlling the reducing process.
(10:30 a.m.1
Preparation of Iron Ore Pellets by Extrusion: A.K. Kuriakose, D.H.H. Quon, K.E. Bell; Energy, Mines and Resources Canada, 405 Rochester St., Ottawa, eanada KlA (x;l Vacuum extrusion studies for the pelletization of hematite concentrates using organic binders, organic binder-calcium carbonate and organic binder-bentonite are re}X)rted. The extrusion urocess provides a convenient method for the Drcxluction of unifonn Pellets. The green strength of t.he ~llets fran all three binder systens is excellent, but onlv the COlTlPOsition containing bentOnite has law to mecli1.ID1 temperature strength sufficient for the induration process
(8:30 a.m.1 VACUUM ELECTRON BEAM REFINING OF COPPER,
A.
\-/.
Fletcher,
9422 E. Placita Eunice, Tucson, Arizolla 85715. Coppc:r produced in Duval's CLEAR process by clectrOl"inning from a strong chloride solution cOlltained silver and certain other im},urities which necessitated treatIng it as blister grade, i.0. it had to be m~ltcd. cast into anodes and electrolytically refined to "athodp grad{~ copppr. An alternate method ' l f 1::'0' f ininq was to rc·move certain i mpuri t1.""S, inc 1 ud inr] silver, b
(11:00 a.m.1
Degradation of direct bonded chrome magnesia J'ricys in secondar u steelmaking under vacuum: D.H.H. Ouon and K.E. Beil. Energy,Mines and Pesources Canada, 405 Rochester St., Otta~'a, Ont., Canada, Kl~ O~l. Failure of direct bonded chrome magnesia rricks from steelmaking ladles was examined in terms of structural characteristics and chemical changes. Refractories degradation is in part caused ry slag infiltration along the grain boundaries of the periclase and spinel. Other factors that cause the failure of refractories are the presence of intergranular phases such as Ca and Si and the loss of ~gO under vacuum at high temperature. All these factors have a great influence in determining the strength of the refractories under operating conditions.
(9:00 a.m. I THE INFLUENCE OF STRUCTURE AND PROPERTIES ON THE GRINDING OF
FERROSILICON: !~~an, Mineral Processing Section, The Pennsylvania State University, University Park, PA 16802, C. N. Kirby, Toms River Chemical Corporation, P.O. Box 71, Route 37~ Bldg. 203, Toms River, NJ 08753 The grinding of a series of ferrosilicon alloys ranging from 5 to 90% Si has been studied. The results can be related to the Fe-Si phase diagram and to the microstructure. Those alloys at 15% Si show an exceptionally high Schuhmann distribution modulus (u=l.OO) below 400 mesh, and grinding them produces but little fines. Other alloys, both lower and higher in Si content, produce more fines on grinding (0:=1.0).
(9: 30 a.m. I
APPLICATIONS OF COPPER OXYCHLORIDE CHEMISTRY TO COPPER EXTRACTION FROM COMPLEX HYDROMETALLURGICAL SOLUTIONS, D.C.McLean, 18388 Jesus Maria Road, Mokelumne Hill, Ca. 95245 Copper oxychlorides (atacamite) are compounds which have received little recognition as viable process intermediates in complex copper-base metal hydrometallurgical circuits. They permit clean, simple separations of copper fr0m base and precious metals and the conversion of copper chloride extraction circuits to norm~l sulfate recovery processes. Physical and chemical properties of the oxychlorides are described and several flowsheets are presented to demonstrate practical applications of oxychloride technology.
(11:30 a.m.1 FRACTURE TOUGHNESS AND HOT-STRENGTH OF MgO-CHROME CEMENT KILN RE-
FRACTORIES: Jose' Mendoza , 120 Fulton Hall, University of Missouri-Rolla, Rolla, MO 65401; Paulino Estrada, 120 Fulton Hall, UMR, Rolla, MO 65401; Robert E. Moore, 120 Fulton Hall, UMR,
Rolla, MO
65401.
A group of as-received commercial MgO-chrome refractories were fully characterized and analyzed for room temperature and high temperature mechanical behavior. In a second series of experiments, surfaces of specimens were coated with Portland Cement botch and held to effect equilibrium assemblages of reaction products to simulate practice. These coated specimens were analyzed for reaction phases and effects of same on high temperature mechanical properties, including flexure creep. The thermal shock behavior of these cement kiln refractories with chemically altered surfaces was measured using the "Ho1derbank" test.
98 TMS Annual Meeting
RAPID SOLIDIFICATION TECHNOLOGY FOR TITANIUM ALLOYS II: Alloy Development, General, High Strength, and Low Density Sponsored by the TMS Titanium Committee Wednesday, March 5,1986 Mardi GrasD 8:30a.m. Marriott Hotel Session Chairmen: D. Eylon, Metcut-Materials Research Group, P.O. Box 33511, Wright-Patterson AFB, OH 45433; J. A. Hall, TIMET, Henderson Technical Laboratory, P.O. Box 2128, Henderson, NV 89015
(8:30 a.m.) PROSPECTS FOR ALLOY DEVELOPMENT OF NOVEL TITANIUM ALLOYS US ING RAPID SOLIDIFICATION: H. B. Bomberger and F. H. Froes, Air Force Wright Aeronautical Laboratories, Materials Laboratory, AFWAL!MLLS, Wright-Patterson AFB, OH 45433
The attributes of rapid solidification have been used to date to develop new and improved alloys in a number of alloy systems such as aluminum. The advantages of rapid solidification include extended solubility, fineness of microstructure, and formation of metastable crystalline or amorphous phases. The prospects for alloy development in the titanium system using rapid solidification will be discussed in the context of the phase diagrams which occur in this system. Specific systems likely to give enhancements of strength, temperature capability, and reduced density will be presented.
(9:00 a.m.) CHARACTERISTICS OF TITANIUM ALLOY PO"'DERS PRODUCED BY DIFFERENT RAPID SOLIDIFICATION METHODS*: T. C. Peng, S. M. L. Sastry, and J. E. 0' Neal, McDonnell Douglas Research Laboratories, P.O. Box 516, Dept. 224, Building 110, St. Louis, MO 63166
Titanium alloy powders solidified at 10 3 K/s were successfully produced by electron beam melting and splat quenching, lasermelting/ spin-atomization, and centrifugal atomization methods. The dependences on process parameters of powder morphologies, size distributions, and dendrite arm spacings were determined. The microstructures of the powders produced by different methods related to the extent of undercooling and cooling rate. effectiveness of the techniques for the production of titanium alloy powders with beneficial microstructures and improved properties was determined. under the McDonnell Douglas Corporation Independent Research and Development program.
STRENGTH TITANIUM ALLOYS VIA RAPID SOLIDIFICATION: P. R. , Air Force Wright Aeronautical Laboratories, Materials Laboratory, AFWAL/MLLS, Wright-Patterson AFB, OB 45433*; I. Weiss, Wright State University, Dayton, OH 45435; I. A. Martorell, Westinghouse Electric Corporation, Pittsburgh, PA 15236; and F. H. Froes*
The development of high strength titanium alloys using a rapid solidification (RS) approach has been studied. Additions of boron, carbon, cerium sulfide, and erbium have been made to Ti-6Al-4V, Ti-IOV-2Fe-3Al, Ti-15V-3Cr-3Sn-3Al, and Ti-20Mo in an attempt to dispersion or precipitation strengthen these alloys. Extended metastable supersaturation has been obtained under RS conditions utiUzing the pendant drop mp.lt extraction (PDME) process. Subsequent heat treatments were conducted to precipitate both alpha phase and the dispersoids mentioned above for age hardening and to simulate compaction cycles. Ribbon characterization including optical, SEM, TEM, microhardness, tensile, and microprobe analyses has been conducted in the asproduced and heat treated conditions. Effects of grain refinement, precipitation, and dispersion on strength have been evaluated and will be discussed.
(9:50 a.m.) RAPID SOLIDIFICATION OF TITANIUM-EUTECTOID FORMER ALLOYS: S. Krishnamurthy, Metcut-Materials Research Group, P.O. Box 33511, Wright-Patterson AFB, OH 45433; 1. Weiss, Wright State University, School of Engineering, Dayton, OB 45435; A. G. Jackson, Systems R~search Laboratories, Inc., 2800 Indian Ripple Road, Dayton, OH 45440; D. Eylon, Metcut-Materials Research Group, P.O. Box 33511, Wright-Patterson AFB, OH 45433; and F. H. Froes, Air Force Wright A.eronautical Laboratories, Materials Laboratory, AFWAL!MLLS, Wright-Patterson AFB, OH 45433
The application of rapid solidification processing to titanium alloys has been the subject of number of recent
investigations. In this work, alloy systems containing beta eutectoid forming additions such as Ni. Co, Cr. and W were studied. Binary and ternary alloys have been rapidly solidified by chill block melt spinning. The microstructural characterization and aging response of rapidly solidified and baseline wrought conditions were studied by SEM, STEM, and microhardness measurements.
(10:15 a.m.) RAPIO SOLIDIFICATION STUDIES IN EUTECTOIO FORMING Ti ALLOYS: L.S. Chumbley, M.A. Ohls, H.L. Fraser, Dept. of t-'etallurgy, Univ. of Illinois, 1304 W. Green, Urbana, IL 61801 Rapid solidification studies were carried out on the Ti-Si and Ti -Cu systems. The work involving the Ti -Si all oys concentrated on understanding the microstructural evolution during rapid solidification. The microstructure of rapidly solidified material produced via laser surface melting (LSM) was found to differ from that produced using melt spinning (MSR) techniques. The role of 0 contamination was also found to be of importance. The trends observed in thi s system were compared and contrasted with those seen in Ti-Cu, where the eutectoid composition occurs at a higher solute concentration. This system exhibits similar LSM and MSR microstructures. In addition several Ti -Cu-Er alloys were investigated and the processing steps necessary to form a stable, strengthening Er203 dispersion were determined. This involved the production of rapidly solidified material via LSM or MSR and subsequent heat treatments. (10:40 a.m.) MICROSTRUCTURES OF RAPIDLY SOLIDIFIED Ti-Al-Li AND Ti-Mg ALLOYS*: S. M. L. Sastry, J. E. O'Neal, and T. C. Peng, McDonnell Douglas Research Laboratories, P.O. Box 516. Dept. 224, Building 110, St. Louis, MO 63166
Large density reductions can be achieved by alloying of titanium with lithium and magnesium. However, preparation of Ti-Li and Ti-Mg alloys by conventional methods is not feasible because of the large differences in melting points of Ti, Li, and Mg and the vaporization of Li and Mg at temperatures required to melt titanium. Elemental powder blending and consolidation followed by electron-beam melting/splat-quenching, and plasma-melt spraydeposition techniques were used to prepare rapidly solidified Ti-Al-Li and Ti-Mg alloys. Phase compositions and distributions were determined by x-ray diffraction and electron microscopic techniques. The potential of rapid solidification processing for microstructural refinement and property improvement of the alloys was determined.
*Research
conducted under the McDonnell Douglas Independent Research and Development program.
Corporation
(11 :05 a.m.) INVESTIGATION OF THE TITANIUM-ALUMINUM-BERYLLIUM TERNARY SYSTEM*: L. A. Jacobson and L. E. Tanner, Lawrence Livermore National Laboratories, P.O. Box 808, Code L-389. Livermore, CA 94550
Research in progress is reported on this ternary system, first systematically investigated L5 years ago. Initial studies are concerned with the establishment of the equilibrium phase boundaries in the titanium and alumin!lm corners. Rapid solidification has been employed to determine the extent of the range of glass-forming compositions in the neighborhood of the Ti-TiBe2 eutectic, and to obtain fine, uniform distributions of titanium beryllide particles within an aluminum matrix. The thermal stability of such structures is being investigated as is the crystallization behavior of ternary glasses.
*Supported
by Defense Advanced Research Projects Agency.
REDUCTION TECHNOLOGY V: CHEMISTRY PART A Sponsored by the TMS Light Metals Committee Pontchartrain Ballroom D Wednesday, March 5,1986 Sheraton Hotel 8:30 a.m. Session Chairman: Michel Gilbert, Alcan International Ltd., P.O. Box 1250, Jonquiere, Quebec, Canada G7S 4K8
(8:30 a.m.) EVOLUTION OF ELECTROLYTES FOR HALL HEROULT CELLS: N. E. Richards Reynolds Metals Company, P.O. Box 1200 Sheffield, AL 35660
While it is axiomatic and almost trite that no aluminwn can be produced electrolytically but that it originates from alumina dissolved in a cryolitic solvent, there have been interesting
TMS Annual Meeting 99 driving forces for those solvents. The initial patents of Hall and Heroult were surprisingly strong in their claims on options for electrolytes. In this review, the likely strategies, through the evolution of knowledge, contrasting properties, which impact a performance on regula tory constraints, are addressed. Conjecture on further opportunities and developments are offered.
(9: 15 a.m.) LOW-MELTING BATHS IN ALUMINIUM ELECTROLYSIS: K. Grjotheim, Dept. of Chemistry, Uni versi ty of Oslo, N-0315, OSLO 3, Norway,
tivity, and reduced energy consumption per unit production. have been clearly established in smelting operations. The economic benefit is related to the lithium consumption which can be partly explained by limited co-deposition in themetal. and some lithium migration into the cathode. However neither of these mechanisms provides a complete material balance, and therefore we have attempted to ascertain the preventable losses that occur with various forms of addition. When lithium carbonate is added in a powdered form, it can react vigorously, resulting in losses through sputtering and vaporisation. If the lithium carbonate is added as pressed pellets. or mixtures that have been sintered with bath additives, the rate of dissolution can be reduced. This results in a reduction in the losses of lithium.
H. Kvande, Ardal og Sunndal Verk a.s., P.O. Box 5177 Maj. N-0302
OSLO 3, Norway, and B. J. Welch, Dept. of Chemical and Materials Engineering, The University of Auckland, Auckland, New Zealand The may 1. 2.
bath compositions used presently in the aluminium industry be divided into three groups: Traditional baths with 3-7 wt% AIF , Modified baths with 2-4 wt% AlF , and MgF , 3 2 l!. Low-ratio baths with 8-14 wt% A1F . 3 The physico-chemical properties of these groups of baths are discussed, and low-ratio baths are found to give lower bath temperatures and higher alumina solubilities compared to modified baths. Low-melting baths, capable of giving bath temperatures below gOOOe, may be obtained by a combination of low bath ratio and LiF and MgF additions. Thus, it may be predicted that in the future the tndustry will start using a fourth type of bath: 4. Modified low-ratio baths wi th 15-40 wt% AlF , and some LiF and MgF . 3 2
tiF
(9: 40 a.m.)
(11 : 20 a. m. ) THE STRUCTURE OF ALUMINA DISSOLVED IN CRYOLITE MELTS: Halvor Kvande, Ardal og Sunndal Verk a.s., P.O.Box 5177 Maj., N-0302 OSLO 3, Norway. ~ A strus~ural mod~! with three ~~ygen-containing species:
Al20F6
' is used to calculate their ' A120Fa and Al 0 F 2 2 4 mol fractions in cryolite-alumina melts. For low alumina contents in cryolite all three specie~_are found to be of about equal importance, while Al 0 F ions are dominating at high alumina contents. Incre~~i~g2b2th acidity will favour the relative amount of Al 0F6 ions. Chemical equations for 2 the formation of these species are suggested, as well as possible anode reactions during electrolysis. The occurence of the anode effect is discussed in terms of the present results.
VAPORIZATION STUDIES OF MOLTEN CRYOLITE AND THE EFFECT OF DIFFERENT FLUORIDE ADDITIONS. J. Guzman, K. Grjotheim and T. 0stvold,
Institute of Inorganic Chemistry, The Technical University of Norway I
7034 Trondheim-NTH, Norway.
Vapour pressures above liquid cryolite with additions of respectively LiF, NaF, KF, RbF, CsF, BeF2' MgF?, CaF~, SrF?, BaF2 and AIF3 have been studied using the Boiling---Point!l4ethoa, Mass Spectrometry and X-ray Analysis. The resul ts show that CaF2 does not influence the vapour pressure of cryol i te. I ts vapour pressure is decreased by addi tiona of: LiF, NaF, SrF2 and BaF2
and increased by KF. RbF I
CsF, BeF 2' MgF 2 and AIF 3 •
SOLIDIFICA TlON TMS-AIME General Abstract Session Carondelet Wednesday, March 5, 1986 Marriott Hotel 8:30a.m, Session Chairman: A. Hellawell, Dept. of Metallurgical Engineering, Michigan Technological University, Houghton, MI49931
(10:05 a.m.) A THERMODYNAMIC MODEL FOR THE SYSTEM A1C1 -NaCl-KCl . 3 K. Grande, T. Hertzberg and H.A. 0ye Institute of Inorganic Chemistry, Norwegian Institute of Technology, University of Trondheim, N-7034 TRONDHEIM-NTH, Norway. Vapour pressure studies of the system A1C1 1 -NaCl-KCl have been carried out. The data are used for constructing a thermodynamic model for the system, enabling calculation of activities and vapour pressures. The model is specially useful for prediction of condensation behaviour that is not easily accessible to measurements.
(10:30 a.m.) DTA DETERMINATION OF BATH LIQUIDUS TEMPERATUPES: EFFECT OF LiF. Gary L. Bullard, Dennis D. Przybycien, Center for Technology, Kaiser Aluminum & Chemical Corp., Pleasanton, CA 94566. The cryolite liquidus of Hall cell bath is the temperature at which bath not saturated with alumina undergoes primary crystallization of cryolite. Use of liquidus temperatures in process control requires precise bath analyses and the capacity to predict liquidus from them. Cryolite liquidus temperatures were determined by DTA using bath samples collected from pots; some contained LiF. Bath acidity was analytically determined by a method based on the sinter technique described by the International Standards Organization. Non-LiF bath results were found to vary precisely according to smooth combination of liquiduses in the Na3AIF6-CaF2-AI203 and the Na3AIF6-AIF3-AI203 systems. LiF depresses liquidus by ~9 deg per % for most compositions. The swale in the liquidus surface reported by Brown was not observed under the dynamic conditions of DTA.
\10:55 a.m.) LITHIUM LOSSES DURING ADD1TION AND DISSOLUTION OF VARIOUS FORMS OF LITHIUM CARBONATE TO ELECTROLYTES: G. Kuschel and B.J. Welch, Department of Chemical and Materials Engineering, University of Auckland. and G. French. New Zealand Aluminium Smelters Ltd, Tiwai Point, New Zealand. The technical benefits derived from using lithium modified electrolytes, such as improved current efficiency. increased produc-
(8:30 a.m.) THE FINE STRUCTURE OF EUTECTIC SILICON IN NORMAL AND MODIFIED AL-SI ALLDYS: Shu-Zu Lu and A. Hellawell, Dept. of Metallurgical Engineering, Michigan Technological University, Houghton, MI 49931 Eutectic silicon in AI-Si alloy has been examined by optical, SEM and TEM methods. Normal flake silicon grows anisotropically and has a low twin density; quench modified fibrous silicon is essentially twin free and grows isotropically (non-faceted); silicon modified by sodium contains a very high twin density and the fibers are somewhat faceted; fibrous silicon produced by sodium addition and quenching (doubly modified) also contains a very high twin density. It is concluded that in the absence of sodium the presence of twins is incidental to the growth kinetics but in the presence of sodium the occurrence of twins is vital to the kinetics of molecular attachment. These observations indicate that modification is caused by adsorption of sodium on the silicon-liquid interface.
(8:50 a.m.) MICROSTRUCTURAL DEVELOPMENT IN UNDERCOOLED Sn-Sb PERITECTIC ALLOYS: W. P. Allen and J. H. Perepezko, Dept. of Met. and Min. Engineering, Univ. of WI-Madison, WI 53706. Fine droplet samples were used to study the development of solidification microstructures in Sn-rich Sn-Sb peritectic alloys as a function of undercooling, composition, and thennal hi story. A transition from a cellul ar structure to a supersaturated solid solution was identified with increasing undercooling for compositions up to 12 wt't Sb. The metastable sol id sol ution decomposed at room temperature to a fine twophase di spersion. At higher Sb concentrations, a transition from a dendritic morphology to a dispersed two-phase mixture was observed. Within the peritectic range, catalysis by the SnSb phase appears to limit the undercooling. Nucleation temperatures were measured for slowly cooled samples and al so for those quenched from the liquid state to study thennal history effects. The maximum undercooling achieved varied from Thennal 190'C for pure Sn to 1l0'C for a Sn-17 wt't Sb alloy. analysis provided evidence in support of the Sn-Sb phase diagram proposed by Predel and Schennann.
100 TMS Annual Meeting (9: 10 a.m.) MICROSTRUCTURE OF 3Cr-1.5Mo-0.1V THICK-SECTION ELECTRON BEAM WELDS.· N. H. Packan, J. M. Vitek, and S. A. David, Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831 The feasibility of using high power electron beam welding to weld heavy section steels (100 mm) of a type 3Cr-1.5Mo-0.1V alloy was investigated. The microstructure of the base metal, heataffected zone (HAZ), and fusion zone were evaluated by transmission electron microscopy. The results are correlated with hardness measurements taken across the weld. A drop in hardness found in the HAZ was attributed to partial tempering during welding. Following a post-weld heat treatment, the hardness decreased across the weld, HAZ, and base metal to a uniform level. The electron beam weldment was found to have excellent toughness properties, thereby making it an attractive process for heavy section steel welding. *Research sponsored by the Division of Materials Sciences, U.S. Department of Energy, under Contract No. DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.
(9:30 a.m.) HETEROGENEOUS NUCLEATION IN ALUMINUM WELDS: S. Kou and Y. Le Department of Metallurgical and Mineral Engineering, University of Wisconsin, Madison, WI 53706. Gas tungsten arc welding of thin sheets of commercial 6061 aluminum alloy was carried out under various welding conditions. The formation of fine equiaxed grains was favored by high heat input and welding speed, by arc pulsation, and by arc oscillation. Overlap welds were made and analyzed, and both dendrite fragmentation and grain detachment were ruled out as possible mechanisms for grain refining in the welds. Electron microscopy revealed tiny Al3Ti particles at the center of the equiaxed grains, indicating evidence of heterogeneous nucleation of these grains.
(9 :50 a.m.)
THREE-DIMENSIONAL WELD POOL CONVECTION DURING ARC WELDING: S. Kou and Y. H. Wang, Department of Metallurgical and Mineral Er19ineering, University of Wisconsin, Madison, WI 53706. A computer model was developed to describe three-dimensional convection in a weld pool produced by a moving gas tungsten arc. ca 1 cuI a ted resu lts a greed very well with the weld produced. effects of the gravity force, the electromagnetic force and surface tension gradient on the convection pattern and weld geometry were demonstrated with the hel p of the computer
and discussed. In the light of scanning electron microscopy and microprobe analysis of the cracked zones, an explanation of the hot tearing mechanism is introduced.
(10:50 a.m.) PROCESS VARIABLES EFFECTING LIQUID METAL FLOW THROUGH A PACKED CERAMIC COLUfIN: F. M. Hosking. Sandia National Laboratories. Al buquerque. NM 87185. The influence of particle size (3 to 9 mm), particle preheat (477 to 700 K), and pouring temperature (1033 to 1144 K) on the infiltration of a' gravity fed, molten aluminum alloy (6 wt.% Mg, balance Al) into a packed column of coarse boron carbide particles was determined. Particle size had the most significant effect on metal penetration. Mild interaction effects between particle size-particle preheat, particle size-pouring temperature, and particle preheat-pouring temperature were also established. Maximum penetrations of 120 mm were achieved near the 9 mm, 700 preheat, and 1144 K pour region of the test matrix. Penetrations as low as 7.0 mm were obtained for the 3.0 mm, 477 K preheat, nod 1033 K pour. A first approximation model was developed to estimate metal infiltration. The analytical and experimental results compared favorably well.
*This work was supported by the U. S. Department of Energy (DOE) under Contract Number DE-AC04-76-DP00789.
(11: 10 a.m.) EFFECTS OF FORCED CONVECTION DURING THE CONTROLLED SOLIDIFICATION OF TIN: Ch. Vives and Ch. Perry, Laboratoire de MagnHohydrodynami que, UnlVers 1 te d' Avi gnon, 84000 Avi gnon, France. The role of natural and forced convections during sol idification of pure tin in an annular crucible was stUdied. The forced convection was generated by electromagnetic stirring. Maps of electromagnetic body forces and velocity fields were obtained for various stirring intensities and various positions of the solidification front. Temperature measurements made it possible to follow both the evolution of the solidification front and temperature distributions inside the bulk liquid with time. These experiments were carried out from various degrees of superheat both in the absence and presence of e 1ectromagneti cst i rri ng. Finally, the macrostructure of the solidified melt was examined. Thi s experimental work reveals the primary hydrodynami c effects on the thermal and meta 11 urgi ca 1 phenomena ; parti cuI ar ly, the crystals growth is consistent with the evolution of the metal flow patterns.
e1. (11:30 a.m.) 10: 10 a.m.) STUDY OF DISSIMILAR METAL WELD HOT-CRACKING INVOLVING PH ~RTENSITIC STAINLESS STEELS: M. J. Cieslak. Sandia National ahorAtor; .. ~~ Albuquerque, NM 87185.* susceptibility· to hot crac~ing in high energy denSity (continuous C02 and pulsed Nd:YAG laser and electron beam) fusion welds between PH martensitic stainless steels (17-4 PH, 15-5 PH, PH ) and either Kovar or HP-9-4-20 has been Investigated using ~otallography, scanning electron microscopy (SEM), and electron microscopy (AEM). All welds were observed to as austenite. No welds involving PH 13-8 Mo were found to hot All pulsed laser welds involving either 17-4 PH or 15-5 PH ted hot cr8c~ing, as did most of the continuous mode (C~ or beam) welds. AEM investigation of weld metal extraction and thin foils revealed a Nb(C,N)/austenite eutectic ,nt along solidification grain boundaries, providing the hot crac~ing mechanism in welds involving the Nb containing alloys (15-5 PH. 17-4 PH). *This wor~ performed at Sandia National Laboratories supported by the U.S. Department of Energy under contract No. DE-AC04-76DP00789.
PHASE TRANSFORMATIONS IN RAPIDLY SOLIDIFIED Ni2MO: S. K. Menon, and P. L. Martin, Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM 87545. The structure of Ni-35 at%Mo ribbons produced by melt spinning has been chRracterized by CTEM and AEM. Rapid solidification has been found to produce a supersaturated fcc phase with the cellular boundaries containing a continuous layer of the equilibrium ordered a-NiMo phase. EDX analysiS has shown that the rapid solidification was accompanied by a significant amount of solid state diffusion. Diffraction patterns indicated diffuse SRO maxima at the (l 1/2 0) positions of the fcc reciprocal Eltice. In addition, some regions of the fcc phase showed plate shaped precipitates. Aging of the ribbons resulted in three different precipitates characterized by their morphology and structure: fine ellipsoidal Ni2Mo with the Pt2Mo structure. large blocky particles with the equilibrium d-NiMo structure and thin plateshaped precipitates corresponding approximately to the Ni2Mo compositiono The possible sequences of phase transformations occuring during rapid cooling and subsequent aging will be discussed on the basis of both equilibrium and metastable phase diagrams. (Research sponsored by U.S. Dept. of Energy.)
(11:50 a.m.) (10:30 a.m.) ON THE HOT TEAR FORMATION IN STEEL CASTINGS: M.A. EISa1amoni and A.H. ElSawy, Mech. Design & Prod. Eng. Dept., Faculty of Engineering, Cairo University, Giza, Egypt, and H.A. Madi, Helwan Company for Ferrous Castings, Helwan, Cairo, EGYPT and I.G. Mahfouz, Consultant Engineer, Cairo, EGYPT. This work is addressed to emphas ize the effect of chemical composition, fluidity of the melt and cooling rate caused by the different core materials on the hot tear formation in low and medium carbon steel castings. Both six arm specimens and hot tear test bars were used to! measure the crack length and resistance to cracking as well as hot tearing temperature in the hot zones, for different chemical compos itions. The results showed that intergranular cracking took place just before the end of solidification interval caused by sulphide inclusions. The interrelationship between the chemical composition and each of hot tear length and hot tear resistance is presented
MICROSTRUCTURAL ANALYSIS OF THREE RAPIDLY SOLIDIFIED Ni BASE SUPER ALLOYS: Randy Bowman and Stephen D. Antolovich, Fraci J.I'e & Fatigue Research Laboratory, Georgia Institute of Teclmology, Atlanta, GA. A microstructural and mechanical analysis was performed on rapidly solidified (melt Sp1.ill) Waspaloy, PWA 1480, and MAR-M 246. TEM, SEM and tensile tests were done on the ribbons in the as-cast and aged conditions. Correlations were made between cooling rate, microstructure, and mechanical properties. Mel t spiIIDing significantly altered the characteristics of the alloys studied. The rapid cooling rates produced ribbons with low dislocation densities, small ('\,llJlll) low angle cells and precipitation of y' was suppressed. Also, the matrix/precipitate lattice mismatch was larger in the melt spun foils. Tensile strengths were similar to those in the conventional form, however no measurable duct iIi ty was present. Aging increased the y' volume fraction, tensile strengths, and elongation over the ascast ribbons. Also, the APBE was higher in the aged condition. These results suggest that many of the microstructural refinements produced by melt spinning are lost after even a short
TMS Annual Meeting 101 aging time at moderate temperatures. Acknowledgement: The authors gratefully acknowledge NASA (NAG 3-503) and the AFooR (840101) for support of thi s work.
STOCHASTIC APPROACHES TO FRACTURE II Sponsored by the ASMIMSD Flow and Fracture Committee Wednesday, March 5, 1986 Mardi Gras K 8:30 a.m. Marriott Hotel Session Chairman: D. Hasson, US Naval Academy, Department of Mechanical Engineering, Annapolis, MD 21402
(10:45 a.m.) MODELING OF LOCAL STRAINS IN DUCTILE FRACTURE: An thony w. Thompson, Carnegie-Mellon University, Pittsburgh, PA 15213
The local strain around individual nuclei for microvoids in ductile fracture plays a role in most micromechanism models for ductility or toughness. These micromechanisms are very attractive because they allow the influence of microstructure to be explained or interpreted. The strains can be measured in the longitudinal (stress) direction or the transverse (fracture plane) direction; these correspond to microvoid depth and width. Both strains are expected to correlate, and do correlate, with measured fracture toughnesses.
(11: 15 a.m.) STATISTICAL ASPECTS OF MICROSTRUCTURAL CONTRIBUTIONS TO FRACfUR£ PROCESSES: J. D. Embury, McMaster University, Dept. Metallurgy and Materials Science, 1280 Main Street West, Hamilton, Ontario LBS 4L 7 Canada
(8:30 a.m.) CREEP CAVITATION AND FRACTURE:· J. H. Schneibel and L. Martinez, t Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831
Creep fracture 1s due to stochastic cavity nucleation at grain boundaries as well as deterministic growth processes. We employ measured nucleation rates and realistic growth tOOdels in order to model the evolution of measured cavity size distributions in copper, stainless steel and a nickel aluminide (Nil Al-O. 5 at. % Hf-0.2 at. % B). Creep ductilities range from 5 to approximately 100%. In successful undelling we have to take into account internal stress distributions, cavity interlinkage, as well as transitions in growth IOOde with size. The importance of measuring and modelling cavity damage (i.e. fraction of cavitated grain boundary area) in order to understand creep fracture is stressed. *Research sponsored by the Division of Materials Sciences, U.S. Department of Energy under Contract No. DE-ACOS-840R21400 with Martin Marietta Energy Systems, Inc. tGuest scientist at ORNL. Permanent address: Instituto de Fisica, U.N.A.M., P.O. Box 20-364, 01000 Mexico, D.F.
(9:00 a.m.) STOCHASTIC ASPECTS OF CREEP CAVITATION: R. A. Page, J. Lankford, and K. S. Chan, Materials Sciences Department, Southwest Research Institute, 6220 Culebra Road, San Antonio, TX 78284. Creep fracture of both ceramic and metallic systems frequently occurs by the nucleation, growth and coalescence of grain boundary cavities. Recent experimental studies of compression crept ceramics, supported by micromechanical modeling, has identified a number of stochastic aspects of cavitation. The stochastic nature of cavitation arises primarily due to the dependence of both cavity nucleation and cavity growth on grain boundary sliding. A degree of randomness is also imposed by the nonuniform distribution of nucleation sites. The experimental measurements and micromechanical models will be briefly presented and used to support the role of grain boundary sliding. The importance of cavity coalescence will also be discussed.
(9:30 a.m.) STOCHASTIC ASPECTS OF SHEET METAL FORMING: O. Richmond, Processing Division Bldg. B, Alcoa Technical Center, PA 19069
Abstract Not Available
( 10: 00 a. m. )
Many fracture processes occur by damage accumulation which commences at second phase particles or interfaces. Thus in order to produce a realistic model of the process of damage accumulation, cognisance must be taken of the statistical nature of the initial particle distribution and of the damage process. Examples will be shown of the use of the Dirichlet tesselation to chara.cterize the local clustering of particles for a variety of microstructures. In addition a model will be presented to shoW' the linking of the cont;inuum description of damage growth to the statistical description of damage initiation to provide a more realistic model of cumulative damage.
STRESS CORROSION AND EMBRITTLEMENT TMS-AIME General Abstract Session Wednesday, March 5, 1986 Mardi GrasE 8:30a.m. Marriott Hotel Session Chairman: Harris L. Marcus, Dept. of Mechanical Engineering, Center for Materials Science & Engineering, The University of Texas, Austin, TX 78712
(8: 30 a.m.) THE EFFECT OF SULFUR AND !!EAT TREATMENT ON THE STRESS CORROSION CRACKING OF INCONEL X-7S0 UNDER SIMULATED PWR CONDITIONS B. Mis-hra, :!. ;J. Moor~. ~i!1eral R~E:"r.n1.rces Research Ce!'!ter, University of Minnesota, Minneapolis, MN 55455
Severe Intergranular Stress-Co.rrosion Cracking (IGSCC) has been reported in the double-aged Ni-rich superalloy Inconel X-7S0, when used as structural components in the pressurized and boiling water reactors of a nuclear power plant. Microstructural aSpects and mechanical properties of Inconel X-750 have been studied following the single aging treatment in 704 0 - 87l oC temperature range for up to 200 hours. Model heat-treatments have been subjected to the Pressurized Water Reactor (PWR) conditions, i.e., 1150 psi pressure and 290°C temperature, in an automated autoclave interfaced with a constant extension rate tester. Different levels of reducible sulfide species in the alloy have been used to compare the refining techniques. The results are expected to serve as a basis for selecting an acceptable refining and heat-treating procedure to reduce the susceptibility of Inconel X-7S0 to intergranular stress corrosion-cracking (IGSCC).
BREAK
(10: 15 a.m.) ON VOID/PORE DISTRIBUTIONS AND DUCTILE FRACTURE, D. A. Koss, currently at Dpt MatIs Sci and Engg, Penn State Univ, University Park PA 16802; E. M. Dubensky and P. E. Magnusen, Dpt of Metal Engg, Michigan Tech Univ, Houghton, MI 49931
The influence of void/pore distributions on ductile fracture has been modeled experimentally by using two-dimensional arrays of equi-sized holes drilled through the thickness of sheet/plate tensile specimens. When compared to data from specimens containing regular arrays of holes, the results show that ductility is strongly affected by the nature of the hole (void) distributions. In particular, ductility is observed to be dependent on the hole size, area fr,fIction of holes, and especially the minimum spacing between holes. The results are discussed in terms of a sequence beginning with strain concentrating at individual holes and ending with regions of high hole density acting as imperfections which cause shear localization and fracture. This research is supported by the Office of Naval Research
(8:50 a.m.) CHARACTERIZATION OF SURFACE AND STRESS CORROSION RESISTANCE OF PM ALUMINUM ALLOYS, D. J. Chellman, R. A. Rainen, and S. L. Langenbeck, Materials and Processes, Lockheed-California Company, Burbank, CA 91520
Three promiSing classes of aluminum alloys produced using RST techniques have been evaluated in terms of their corrosion resistance. The present work addresses the surface and stress corrosion performance of candidate elevated temperature PM Al-Fe-X alloys. damage tolerant PM 2XXX alloys, and high strength PM 2124 reinforced with SiC whiskers. The corrosion characteristics of these materials were established using a variety of standard accelerated laboratory tests. and comparisons were made with conventional aluminum alloys. Long t..erm seacoast exposure tests were performed to correlate with the accelerated environments. The surface corrosion resistance of the PM Al-Fe-X alloys was found to compare favorably with conventional corrosion resistant alloys such as 6061 and 5083. Surface and stress corrosion resistance of the PM 2XXX aluminum alloys appear to be similar to that of 1M 2024 in equivalent tempers. In addition. corrosion characteristics for these materials have been correlated with microstructural observations in the three alloy families.
102 TMS Annual Meeting (9: 10 a.m.) INTERGRANULAR STRESS CORROSION CRACKING OF SENSITIZED NONMAGNETIC Cr-Mn-N STAINLESS STEELS IN CHLORIDE-CONTAINING ENVIRONMENT: H. G. Chun, Z. El iezer and H. L. Marcus, Department of Mechanical Engineering, Center for Materials Science and Engineering, The University of Texas, Austin, Texas 78712. Chloride-environment intergranular stress corrosion cracking in welded nonmagnetic Cr-Mn-N stainless steel structures is a serious problem. In this study, six different nonmagnetic Cr-Mn-N stainless steels (two commercial and four research alloys with different impurity levels) based on 18Cr-18Mn-N and 18Cr-13Mn-N alloys, were selected. Slow strain rate SCC testing was performed in chloride-containing environment. SEM, Auger electron microscopy (AES), Secondary ion mass spectroscopy (SIMS) and X-ray photoelectron spectroscopy (XPS) were used to study the effect of alloying elements (Cr, Mn, Ni and N) and impurities (P and S) in the SCC behaviors. The effect of the preci pitates (Cr-carbi des and Cr-ni tri des) on the IGSCC in the aged and welded specimens will be discussed. This research was supported by the Office of Naval Research under contract no. N00014-83-K-0143.
(10:30 a.m.) THE EFFECT OF Al ON 475C EMBRITTLEMENT OF FERRITIC STAINLESS STEELS: W.S. Spear, Boeing Aerospace Co., P.O. Box 3999, MiS 7309, Seattle, WA 98124, D.H. Polonis, Dept. Mat. Sci. and Engr .• University of Washington, Seattle, WA 98195.
The effect of Al on the magnitude and kinetics of the 475C embrittlement reaction in Fe-Cr ferritic stainless steels has been examined. The precipitation of Cr-rich ferrite. a'. which is responsible for the embrittlement has been studied in steels containing 15 to 18 wlo Cr with ternary additions of 3 to 6 wlo Al over the range 400 to 550C for times up to 4000 hr. The structural changes associated with the reaction were monitored by electrical resistance, microhardness. and TEM techniques. The results were compared with those of a 18 wlo Cr binary alloy. While additions of Al increase the stability of these alloys with respect to a' precipitation. the solid-solution strengthening effect of Al along with greatly increased carbo-nitride precipitation lead to other embrittlement effects. The transformation kinetics and microstructural changes accompanying these reactions are discussed.
(10:50 a.m.)
(9:30 a.m.) DISLOCATION DISTRIBUTION IN TRANSGRANULAR STRESS-CORROSION CRACKING OF NAVAL BRASS L R. Kramer, B. Wu and C. R. FeoR, Metallurgical Haterials Laboratory, University of Maryland, Collee€ Park, tID 20742. The dislocation density, as calculated from the rms microstraios, was determined on specimens of Naval brass strained at a rate of 10-5 sec-1 in 0.1 M Cu5040 The microstrains were determined from
a Fourier analysis of the X-ray diffraction lines. The data show that in transgranular stress-corrosion cracking of Naval brass the environmental condition causes the dislocation density to increase rapidly with strain. Independent of the applied voltage cracks were formed when the dislocation density in the surface layer and in the interior increased to corresponding critical values that were independent of the strain history. Periodic removal of the surface layer during straining decreased the rate of increase of the dislocations in the interior of the specimens and extended the stress-corrosion life. It appears that cracks are initiated when the stress fields associated with the accumulation of dislocation in local regions together with the applied stress are equal to thE local fracture stress.
HYDROGEN PERMEATION MEASUREMENTS IN LANTHANIDE (RARE-EARTH) TREATED Z~ Cr-IMo STEEL. Gordon A. Sargent::;~, M. Fernandes):': and G. A. Ratz*';'. ':
2i
Institute of Metals Lecture Light Metals Luncheon
See Page III
WEDNESDAY PM 9:50 a.m.) EFFECT OF BORON ON HARDENABILlTY AND TEMPER EMBRITTLEMENT IN -FREE LOW ALLOY STEELS: Y Milo, National Institute for Maters Research, CSIR, Pretoria, South Africa. tudy has been carried out to investigate the substitution of s elements (ma i n =Ly 80ron) to replaceD. 3perecent mol ybena low alloy steel (en 19). Small quantities of boron were at the melt stage in two forms in as ferroboron (14.4 perand as complex ferroboron (6 percent 8 30 percent TI 15 Al and 10 percent SI). An optimum effective boron conwas i dent ifi ed for both cases. The add i t i on of boron as omplex ferroboron produced better hardenabil ity which was optimzed at a lower final boron level than when simple ferroboron was sed as the melt add i t i ve. It was found that 15 PPM boron cou 1d ectively SUbstitute for 0.3 percent molybdenum in EN 19 steels. imum austenitizing temperatures are also determined for hardenlity. In general boron was found to be less effective than ybdenun in preventing temper embrittlement but in spite of s 10 PPM boron was found to be as effective as 0.1 perecent num. It was also confirmed that boron has NBO detectable on temper softening resistance frsulting in the possibility of using lower tempering temperatures and shorter tempering times than would be advisable for molybdenum containing alloys.
CHEMICALLY INDUCED INTERFACE MIGRATION I Sponsored by the TMS Chemistry and Physics of Metals Committee and the ASMIMSD Computer Simulation in Materials Science Committee Wednesday, March 5,1986 Mardi Gras K 2:00 p.m. Marriott Hotel Session Chairman; D. N. Yoon, Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Seoul, Korea (2: 00 p.m.)
INTERFACE STRUCTURES l'ORl'lED DURING CP.H'ICALLY INDUCED BOUNDARY 'lIr:RATION, D. A. Smith, IE" Thomas cT. VJatson Research Center, Yorktown Heights, J'!Y 10598.
During alloying hy diffusion along
g~ain
boundaries
it is inevitable that any size differences between the
solute and solvent cause Misfit stress.
(10: 10 a.m.) THE ROLE OF NOLYBDENU'I IN DECREASING THE PHOSPHORUS-EMBRITTLEMENT OF STEELS: S.S. Brenner, Department of Metallurgical and Naterials Engineering, University of Pittsburgh. Pittsburgh, PA 15261 and R. Moller and H.J. Grabke, Max Planck Institut fur Eisenforschung, 4000 Dusseldorf I, FRG.
Nolybdenum decreases the temper embrittlement of certain phosphorus-containing steels. It has been proposed that this beneficial effect results from the formation of Mo-P clusters. which lowers the concentration of phosphorus at the grain boundaries. Atom probe analyses of laboratory-prepared alloys of Fe-Mo-P and Fe-Mo-P-C failed to show the occurrence of such clusters. Instead it was found that in the carbon-containing alloy the concentration of phosphorus was appreciably enhanced in the vicinity of M02C precipitates. The beneficial role of molybdenum in reducing the temper-embrittlement of steels can be readily explained by this trapping effect.
Indeed this
process is the basis for Hillert's mechanism for DI~M. The purpose of this paper is to present the results of an investigation (theoretical and experimental) into the nature of the interfaces which may be formed het",een alloyed and unalloyed regions. Key aspects of this work are the modification of the grain boundary structure upon alloying and the loss of coherence between the alloyed and unalloyed zones. T;,e result is some convergence IJetween the atomistic model of Dalluffi, Cahn, I:ing and Smith and the thermodynamic analysis of Ilillert. (2:30 p.m.) ASPECTS OF DIGM IN THE IRON-ZINC SYSTEM: Glyn Meyrick, Dept. of Metallurgical Engineering, The Ohio State Unlverslty, 116 West 19th Avenue, Columbus, OH. 43210. The morphological changes produced at grain boundaries by DIGM in Fe exposed to Zn vapor will be reviewed. These changes range
TMS Annual Meeting 103 from normal boundary mi gra ti on to processes that eventually create three boundaries from the original one. Electron channelling patterns reveal no obvious correlation between misorientations across boundaries and the type of morphological change that occurs. Experiments involving cyclic zincification and dezincification and also successive treatments to the same boundaries suggest that the changes are not reproducible and that a given boundary will not necessarily give rise to a particular type of change. These observations are discussed in terms of ideas put forward to explain DIGM.
(3:00 p.m.) DEPENDANCE OF CIGM IN CALCITE ON GRAIN BOUNDARY STRUCTURE,
B. Evans and R. S. Hay, Department of Earth and Planetary Sciences, MIT, Cambridge, MA Chemically induced grain boundary migration has been observed in calcite (CaCo3) bicrystals exposed to a high activity source of SrC03 or BaC03_ Migration morphology and chemical composition of the crystal volume through which CIGM occurred are observed to have a strong dependance on both magnitude and direction of the grain boundary misorientation vector. Large differences in 0 morphology are observed among low angle boundaries (0.5 5°) with similar magnitude but different directions of the misorientation vector. A similar, but less well developed trend has been observed in high angle boundaries. High angle boundaries always leave a much larger amount of cation solute in their wake than low angle boundaries. Although exceptions exist there are pronounced differences in the extent and form of boundary migration between high and low angle boundaries.
(3:30 p.m.) COMPARATIVE STUDIES OF DIGM IN THE COPPER-ZINC SYSTEM: SOME NEW CONTRIBUTIONS TO THE PHENOMENOLOGY: A. H. King, Dept. of Mat. Sci. & Eng., State University of New York, Stony Brook, NY 11794. A technique has been developed for measuring the average extent to which DIGM occurs in a given polycrystalline specimen: this enables comparative studies between specimens treated differently and thus provides a means for performing critical tests of different models of DIGM. Grain size, prior cold work, surface contamination and time have all been shown to affect the rate of alloying by means of DIGM, and work is underway on other parameters. It is clear that complicated behavior occurs in DIGM and it is likely that more than a single mechanism may be operative (even in a single system). Comparison of the observed phenomenology with models based on the grain boundary dislocation climb mechanism indicates that this is still a strong candidate, at least in the Cu-Zn system. Acknowledgment: This work is supported by the National Science Foundation under grant # DMR8216188.
(4:00 p.m.) DIGM,SIGM,LFM AND BOUNDARY MOBILITY IN W-(Ni) AND Mo-(Ni),
W.A.Kaysser and G.Petzow, Max-Planck-Institut fUr Metallforschung,Institut fUr Werkstoffwissenschaften,PML,7000 Stuttgart, FRG.
continuous, or discontinuous migration depending on the values of the parameters. In continuous migration the equation predicts migration with uniform velocity.
CORROSION AND OXIDATION TMS-AIME General Abstract Session Wednesday, March 5,1986 Mardi Gras L-M 2:00 p.m. Marriott Hotel Session Chairman: William A. T. Clark, Dept. of Metallurgical Engrg., The Ohio State University. 116 West 19th Ave .• Columbus, OH 43210
(2:00 p.m.) THERMODYNAMIC AND KINETIC MODELING OF SENSITIZATION IN AUSTENITIC STAINLESS STEELS:* T.Arul Mozhi. W.A. T. Clark, S.E. Wilde. Dept. of Met. Eng., Ohio State Univ •• Columbus, Ohio 43210. Theoretical models used to calculate: 1) time-temperature-sensitization (TTS) diagrams, 2). chromium con.centration at the carbide-austenite interface (x\ ), and 3) chromium concentration profiles in the vicinity of brbides, as a function of alloy composition and sensitizing temperature and time for AISI 304 and 316 stainless steels, show that sensitization is retarded with decreasing carbon and increaSing nitrogen levels. The calculated and experimental TTS diagrams obtained using the electrochemical potentiokinetic reactivation (EPR) tests and the modified Stra¥ss test are compared, as are calculated and experimental x and chromium concentration profiles obtained using the analyfrcal electron microscope (AEM). The calculations and AEM results are correlated with the corrosion behavior of the alloys. *Thi s work was supported partly by the Dept. of Energy under Contract #DE -AG02-81ERI0972, and the Lawrence Livermore Nat; ona 1 Labora tory.
(2:20 p.m.) A NEW APPROACH FOR THE COMPUTATION OF EH-pH DIAGRAMS FOR M-S-HZO SYSTEMS, S.M. EI-Raghy and M.R. EI-Demirdash, Dept. of
Metallurgy, Faculty of Engineering. Cairo University, Cairo, Egypt.
A new approach is suggested to establish E -pH diagrams for M-HZO and M-S-HZO systems. Each species i~ assumed to be the primary product of a reaction between me~al, sulfur (or both) and water, with possible liberation of H ~nd el~ctrons in reactions of the form: M + wHZO = xX + mH + ne • This primary product. X, is assigned an actIvity term representing its stability. At any EH-pH level, the species of maximum stability is identified in a point-by-point scanning way; diagrams are computer-plotted. Results of this work on Fe-, Cu-Ag-, Mo-, S-H 0 systems are compared with the literature. In some cases, 2 differences are found between the diagrams and those found in the literature. The program is capable of establishing diagrams for temperatures up to 250°C.
Grain boundary and liquid film migration has been investigated by annealing W or Mo in the presence of Ni. Evidence for DIGM
and LFM is found in W single crystals and Mo foils of low dislocation density. The migration is found to stop when the boundaries develop facets. The migration rates and the dependance of the solid solution lattice parameter on Ni concentration have been determined and are compared with the recent theory of"DIGM" based on the stresses induced by asynnnetrical concentration fields normal to the boundary. Severe discrepancies remained. Plastic deformation of IV or Mo prior to DIGM experiments causes boundary migration by SIGM i~ th dislocation density difference at the boundaries exceeds 10 fern. The transformation from SIGM to DIGM has not been observed.
z
(4:30 p.m.) UIFFUSION INDUCED GRAIN BOUNDARY MIGRATION (DIGM) STUDIES IN COPPEK-ZINC SYSTEM: C. S. Pande, M. A. Imam. L. E. Richards, and ~. B. Rath, Naval Research Laboratory, Washington, OC 20375-5000 Experi menta 1 and theoret i ca 1 studi es of the phenomenon of diffusion induced grain boundary migration (DIGM) is reported. Experimentally DIGM and related effects have been studied in copper and copper-zinc specimens exposed to zinc vapor from powders of Cu-lOUn, Cu-15:=linc and Cu-301,zinc alloys. Surface relief has been observed on grain boundaries and twin boundaries. In addition, geometrically shaped structures are observed inside the grains often oriented in particular directions. A mathematical relation is obtained by considering the rapid diffusion along the grain boundary, and much slower diffusion in the matrix. The solution of this equation leads to
(2:40 p.m.) THE EFFECT OF COLD WORK AND SUBSEQUENT TEMPERATURE AGING ON PITTING CORROSION OF 316L STAINLESS STEEL:*I.T. Nam, R.T.Mullis,
Y.K. Hong, P.S. Chen and R.C. Wilcox, Materials Engineering Porgram, Department of Mechanical Engineering, Auburn UniverSity, Auburn, Alabama 36849. Pitting corrosion tests were conducted on 316L stainless steel cold-worked under the deformations of 20 and 50% in NaCl solut ion us ing e Ie ct rochemical t e chn iqges. The effect of heat treatment at 650, 735, 815 and 900 C for up to 1000 hours on the pitt ing corrosion, hardness and microstructure of previously cold-worked specimens was also studied. The only non-coldworked specimen aged at 8lSoC showed a linear increase in the hardness from 100 to 1000 hours. Electrochemical tests indicate that the inc~ease in degree of deformation, aging temperature and time decreases the resistance of specimen to the pitting 0 corrosion. The aging temperature of 900 C has only minor effect on the pitting corrosion. These results will be discussed in terms of the microstructural variations in the aged specimens. *Supported by Auburn University under grant No. HONG ME-Nl-85.
(3:00 p.m.) SIMULTANEOUS CHROHIZING-ALUMINIZING OF AUSTENITIC STAINLESS
STEELS. S.C. Kung, S.D. Scarberry, D.M. Miller, R.A. Rapp, 116 W. 19th Avenue, Columbus, Ohio 43210, Dept. of Metallurgical Engineering, The Ohio State University. Chromium and aluminum were codeposited onto an austenitic stainless steel substrate simultaneously by a single step pack cemen-
104 TMS Annual Meeting tat ion process to improve the corrosion resistance at higher serAn increase in the operation temperatures
CRACK PROPAGATION
from 550 C to 650 C and higher would greatly benefit the effi-
TMS-AIME General Abstract Session Wednesday, March 5,1986 Mardi Gras E 2:00p.m. Marriott Hotel Session Chairman: W. M. Garrison, Jr., Dept. of Met. Engrg. & Matis. Science, Carnegie-Mellon University, Pittsburgh, PA 15213
vice temperatures.
ciency of energy consumption in the utility industry. However, this increase in temperature requires the use of materials Hith improved creep strength. The mechanical strength of austenitic
stainless steels are suitable and their corrosion resistance can be enhanced by enriching the surface composition in aluminum using a pack cementation process. The mechanisms of the formation of diffusion coated products on 3045.5. are discussed. The morphologies of the phases formed on the surface, namely Sand an interdiffusion two-phase zone, are presented. Also, efforts to avoid the formation of a brittle outer layer of S phase by variations in the pack compositions and activators are discussed.
(2:00 p.m.)
(3:20 p.m.) SIMULTANEOUS CHROMIZING-ALUMINIZING OF IRON AND IRON-BASE ALLOYS. ~_~~, S. C. Kung, and R. A. Rapp, 116 H. 19th
Avenue .. Columbus, Ohio 43210. Dept. The Ohio State University.
0[
Metall·jrgical
En~ineering
Iron-base alloys used in petrochemical plants, utility bo~lers, coal gasification systems, etc. are frequently subjected to high temperature (700-l200 0 c) corrosion problems. To achieve the necessary combination of corrosion resistance and strength, strong substrate alloys are usually coated with chromium and aluminum to improve their high temperature performance. In this research, both chromium and aluminum have been codeposited and diffused into iron and iron-base alloys by a single step pack cementation process without further heat treatment. The result is a Kanthal-like alloy surface composition (20Cr-4Al-Fe) ""hich provides the excellent high temperature oxidation resistance. The influences in the pack composition of the ffiasteralloys, activators, and additives (Zr, Ii, Y, etc.) will be discussed. Cyclic oxidation testing and TCA results are presented to demonstrate the effectiveness of this coating process.
(3:40 p.m.)
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HIGH TEMPERATURE CYCLIC OXIDATION OF ALUl-1INISED TITANIUM, J,Subrahmanyam and J, Annapurna, Defence Metallurgical Research Lab, Hyderabad-500258, India, " or oxidation resistance of titanium is one of the , factors to limit its use for high temperature . ications, Several alloying additions are prely being c~nsidered to improve oxidation res isof titanium, An al ternati ve approach is to op a surface protective coating, Pure titanium uminised using a conventional pack cementation ' - s, Bulk of the coating consists TiA13, which subsequently annealed to give TiAl on the Isurface, Cyclic oxidation tests with one hour at OO-lOOO·C and 20 minutes at rOOm temoerature were onducted on both TiAl and TiAl surface layers. hese layers show consIderable improvement in oxida_ ion resistance compared to pure titanium, Protruded de regions 1Oe:e. observed at 900 and 950·C on sed TiA13 samples, A rutile phase forms on the surface with an inner aluminum oxide layer,
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(4:00 p.m.) OGEN OETERMINATI ON US ING THE SOLI D ELECTROLYTE HYDROGEN YL PHOSPHATE TETRAHYDRATE: S. B. Lyon and D. J. Fray, I " . rtment of Metallurgy and Materials Science, University of ri dge, Pembroke 5 treet, Cambridge, CB2 30Z, Engl and. There is a need to be able to detect hydrogen at ambient temperature both in the environment and dissolved in metals. A sol id-state cell has been constructed wi th hydrogen uranyl phosphate tetrahydrate as the electrolyte and HXW03 as the reference electrode. For hydrogen in nitrogen, a Nernstian response was found down to 1 ppm. Hydrogen was introduced into iron samples and the activity of hydrogen determined using the cell. Possible applications of the device include the detection of hydrogen generated by corrosion processes, e1ectroplatinq processes. welding and the control of corrosion protection systems.
A STUDY OF THE MECHANISMS WHICH CONTROL CREEP CRACK GROWTH: J C, Earthman, W. D. Nix, Department of Materials Science and Engineering, Peterson Building, Stanford University, Stanford, CA 94305. The influence and control of creep crack growth by different mechanical processes has been studied in Cu and Cu + I wt% Sb at temperatures ranging from 450 to 650'c' Crack growth experiments have been conducted under several different loading conditions including constant C'. The results of these experiments indicate that a coupling of creep damage near the crack tip and power law creep in the ligament control crack propagation early in the life of the specimen. The results also suggest that, later in the experiments, crack growth is only influenced by creep damage mechanisms. Microstructural observations have confirmed this hypothesis and have also provided information on how cavitation facilitates crack growth. A model based on cavity growth by coupled diffusion and power law creep has been developed for crack growth behavior dominated by creep damage. The crack growth rates predicted by this model agree with those observed experimentally.
(2:20 p.m.) FATIGUE CRACK PROPAGATION OF SINGLE CRYSTAL MAR-M200 UNOER MIXED MODE LOADING: O.Y. Chen, Pratt &Whitney Aircraft, E.H., CT 06108, A.J. McEVTlY-;-Un,versity of Connecticut, Storrs, CT 06268 Fatigue crack propagation behavior of single crystal nickel-base superalloy MAR-M200 was studied using CoT specimens at four crystallographic orientations, i.e. [100], [110], [ll1J and [123J orientations. It was observed that fatigue crack propagation occurred exclusively along octahedral [lllJ planes. A two dimensional Boundary Integral Equation (BIE) method was used to calculate both the shear stress intensity factor (KII) and the tensile stress intensity factor (KI) with angled cracks along the [lllJ crystallographic orientation. The role of both tensile and shear stress in governing the crystallographic crack propagation will be discussed.
(2:40 p.m.) CRACK INITIATION AND GRo\lTH UNDER APPLIED CYCLIC COMPRESSIVE LOADS: PART I. THEORY AND EXPERIMENTS S. Suresh, Division of Engineering, Brown University, Providence, Rhode Island 02912.
*
The phenomenon of crack initiation and growth from stress concentrations subjected to fullY compressive ..cyclic loads is examined in detail. Experimental ~esults on the influence of compressive load range, load ratio and overloads on the growth of fatigue cracks under far-field compression is described for a variety of alloy systems. Simple conceptual models as well as numerical analyses are presented to estimate the total distance over which crack growth occurs in compression and the extent of crack closure.
*
Research supported by the U. S. Department of Energy.
(3:00 p.m.) CRACK INITIATION AND GROHTH UNDER APPLIED CYCLIC COMPRESSIVE APPLICATIONS. LOADS: PART II.
*
S. Suresh, T. Christman and C. Bull, Division of Engineering, Brown University, PrOVidence, Rhode Island 02912. The phenomenon of crack initiation at notches under fully compressive cyclic loads has some very important applications in fatigue and fracture. (0 Crack initiation under remote compression can be used as a procedure to estimate fatigue thresholds. While this procedure leads to accelerated measurements of fatigue thresholds as compared to conventional (load-shedding) methods, it also eliminates several uncertainties inherent in the conventional methods arising from the artifacts of load reduction. (ii) Crack initiation under remote compression can he used to gain some insights into the closure characteristics of both long and "short" fatigue flaws. Several issues pert i-
TMS Annual Meeting 105 nent to the applications outlined ahove will he discussed ill detail and the significance and limitations of the c(lmpression method will be outlined.
*
Research supported bv the U. S. Department
CREEP CRACK GROWTH BEHAV lOR IN
Sr~RV
LCE DEGRADED 1', Cr-', Mo
STEEL, A. Saxena, Georgia Institute of Technology, Atlanta, GA, {If
Energv
30332-0245.
(3:20 p.m.) EFFECT OF R RATIO ON FATIGUE CRACK PROPAGATION OF SHORT CRACKS: Jack Telesman, Douglas M. Fisher, NASA Lewis Research Center, TIllOO~rk Road, Cleveland, OH 44135 and Donna Holka, Michigan Technological University, Houston, MI 49931. Testing was performed on single edge notch 7075-T6 aluminum specimens to determine the crack propagation behavior of short cracks. The testing was performed at R ratios 0.1, 0.33, 0.5 and 0.7. A replication technique was used to measure the crack lengths. The smallest cracks resolved by the technique were approximately 10 microns in length. For comparison purposes, near threshold crack growth rates were determined for compact tension specimens. The long crack testing was performed using similar R ratios and the same heat of material as the short crack tests. Crack closure effects were accounted for in the compact tension specimens.
(3:40 p.m.) EFFECT OF BETA HEAT-TREATMENT ON MICROSTRUCTURE AND FATIGUE CRACK PROPAGATION IN Ti-6Al-4V: J. C. Chesnutt and C. G. Rhodes,
Rockwell International Science Center, Thousand Oaks, CA
91360
The authors have previously reported on a study of microstructure, fatigue crack propagation and fracture path correlatioIlS for Ti-6Al-4V plate as a function of beta heat-treatment. In the present work three additional microstructural conditions were produced in beta-forged material. One microstructural condition evaluated was as-forged; the other two were produced by using two of the beta heat treatments from the previous study. Results of microstructural characterization and fatigue crack propagation behavior in laboratory air at R = 0.1 and 0.7 will be presented. Fatigue crack propagation will be correlated with the microstructural and fractographic data obtained, and will be compared to the results previously obtained on plate material. Sponsored by the Air Force Office of Scientific Research under Contract No. F49620-83-C-0055.
(4:00 p.m.) FA,IGUE CRACK GRO\olTH DO\olN LO\oI ENERGY INTERFACES
(4:40p.m.)
IN COPPER DOPED
The creep crack growth rate (da/dt) behavior of a l!,; Cr-~ Mo steel was characterized using compact type and center crack tension specimen geometries. Materials wi th two levels of service degradation were characterized. The material exposed to higher service temperature exhibited inferior creep deformation, rupture and crack growth behavior compared to the material which experienced the lower service temperature. The creep crack growth behavior from the two specimen geometries were characterized by the Ct parameter. Also, the da/dt versus Ct behavior of materials with the two levels of degradation were identical at high crack growth rates and somewhat different at lower crack growth rates. A methodology for applying the creep crack growth data is also discussed.
(5:00p.m.) ELASTIC STRAIN FIELDS AROUND LASER-DRILLED HOLES: Y. H. Chung
and S.R. Stock, School of Materials t:ng., Georgia Inst. of Technology, Atlanta, GA, 30332 Long range, elastic strains around laser-drilled holes were mapped in silicon crystals. The strain field was studied using Lang section topography which combines sensitivity to small strains and spa tial resolution on the order of ten micrometers. Additional Pendellosung fringes were formed in section topographs recorded from the crystal ncar the hole, and the magnitude of the components of strain and their gradients were calculated from these results using the Eikonal formulation of dynamical diffraction. The influence of variables such as the power densi ty of each laser pulse and the total power input during drilling were examined. The surface structure of the holes was observed with SEM and was correlated with the topographic resul ts.
ENVIRONMENTAL CONTROL & HEALTH II Sponsored by the TMS Light Metals Committee , • I Wednesday, March 5,1986 II 2:00p.m.
..
Session Chairmen: S. G. Epstein, Aluminum Washington, DC 20006; and R. C. Dickie, Alumax, Mt. HoI ly, SC 29445
WITH B[SMUTH: * S. Chikwembani and J. Weertman, Dept. of Mat. Sci. and Engr •• Northwestern University, Evanston, IL 60201 When polycrystalline copper is doped with bismuth, se~regation of bismuth to the grain boundaries makes copper brittle via grain boundary cracking. Experiments conducted by Hondros and McLean have established that surface enerlOiY of copper doped wlth bis. muth decreases with increasin~ bismuth content. The Double Slip Plane (DSP) crack model applied to fati~ue crack \-lropa~ation predicts that crack growth rate ~hould be a strong function of the surface energy. We are currently studying changes in fatigue crack growth rates of copper-bismuth bicrystals. The grain boundary offers a unique path for fatigue crack growth in the bicrystals. The crack growth rate, at a given t:.K, is found to increase .... i th Inereasin~ bismuth concentration. The power exponent on t:.K in the Paris equation appears to be approximately 2. *Th l5 research was ~uppor ted by the Na tiona I Sc ienee founda t 10n under NSf Grant DHR-8304644.
(4:20 p.m.) DETERMINATION OF CAVITY GROWTH KINETICS FROM CAVITY SIZE DISTRIBUTIONS: * L. Martinez, t and J. H. Schneibel, Metals and Ceramics Division, Oak Ridge National Laboratory, Oak Ridge, TN
*Research sponsored by the Division of Materials Sciences, wi th Mart in Mariet ta Energy Sys terns, Inc., and by Conacyt-PCCB-
BNA-ofg~~~l ~f~g~Ist at ORNL.
Permanent address:
Instituto de
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ENVIRONMENTAL CONTROL IN OUR INDUSTRY - AN HISTORICAL OVERVIEW: J. P. McGeer, Alcan International Limited, Kingston Research and Development Centre, P.O. Box 8400, Kingston, Ontario, Canada K7L 4Z4. . The aluminum industry has faced and solved many problems in the area of the environment. The one that has had the greatest impact, fluoride evolution from the Hall-Heroult process, is the subject of another paper at this Conference. This presentation will cover the evolution of practices and equipment in other areas including disposal of refinery and chemical plant effluent streams, hydrocarbon evolution, heat and physical stress, disposal of used potlining, disposal of casting plant dross, chlorine flUXing of metal prior to casting, explosion hazards, effluents from remelting scrap, and dusts and noise in many parts of the aluminum production process.
(3:00 p.m.)
U.S. Department of Energy under Contract No. DE-AC05-840R21400
a. a.
37831
We show that the growth rate of intergranular creep cavities as a function of cavity radius may be obtained from a detailed analysis of the evolution of cavity size distributions, even in the presence of continuous nucleation. Analysis of Yang and Weertman t s data on creep cavities in copper with this method confirms quasiequilibrium kinetics. The truncation error of the small angle neutron scattering technique employed by Yang and Weertman is found to be more serious than previously thought.
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THE PERFORMANCE OF THE BLP DISPERSION MODEL & ITS USE AT ALCAN PLANTS: K. Ferguson, Alcan Australia, Kurri Kurri
Alcan at both Grande-Baie, Quebec and Kurri Kurri. Australia has made extensive use of the buoyant line and point source model (BLP) for predicting atmospheric fluoride emissions & their effe:.ts. In this two part papaer modification of the BLP model for use at each location will be described. Field validation of the predicted emissions will also be described with emphasis on the value of the model as an acceptable method to predict actual field conditions. In the case of the Grande-Baie plant the model is shown to be valuable to predict (before plant start-up), the size of buffer zone necessary to protect grazing cattle in Northern Quebec. In the case of the Kurri Kurri plant a 2 year validation of the model is shown as an accurate predictor of atmospheric fluoride levels at an operating plant in Australia.
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106 TMS Annual Meeting p.m.) SAMPLING AND ANALYTICAL METHODS FOR MEASURING CARBON PLANT EMIS'::=
(3,30
J.H. Walker, J.E. Gibb, and J.N. Peace, Aluminum Company of America, Pittsburgh, PA. New sampling and analytical methods anow simultaneous measurement of
particulate, hydrocarbon, fluoride and sulfur emissions from carbon anode prOduction facilities. Alcoa Method 4090"- isokinetical'y samples green mill anode mixing fume outlets at stack conditions for particulate and
total t1ydrocarbons. The 4090A sampling train consists of a nozzle. probe, glass fiber filter, XAO-2 tube before the 4-impinger section containing deionized ~ater and sil1ca g-el at ice tempe·.-ature. A.lcoa Method 4090B samples baking furnace outlets for particulate, hydrocarbons, fluorides and sulfur. The 40906 sampling train consists of a nozzle, heated Psobe, heated filter box maintaining a 1 \.J mesh Tenon filter at 248=25 F. impingers containing 0.1t: sodium hydro)(ide solution, and XAD-2 resin tubes bebeen the third and fourth impingers. Gas Chromatograpny-flame ionization {GC-FlDl measures total hydrocarbons. Hign performance liquid cnromatography {HPlCl with ultra-violet (UV) and fluorescence detectors measures polynuclear aromatic hydrocarbons (PA.H) and benzo-a-pyrene {6-a-Pl const i tuents of the methyl ene chl or; de sol ub 1e hydrocarbons. Wet chern; ca 1 or selective ion electrode methods measure particulate and gaseous fluorides. Wet chemical methods determine sulfur.
(4,00 p.m.)
CATALYTIC INCINERATION OF PITCH MELTER FUME: W.H. Minchin, Alcan Smelters and Chemicals Ltd., Kitimat, B.C. V8C 2H2, Canada
At Kitimat, solid coal tar pitch is melted by liquid pitch at 210°C and flows to a storage tank where it is held at about 195°C. Fume evolved during pitch melting must be controlled. Fume can be condensed, then recovered to be disposed of separately, or can be returned to the main body of pitch to reevolve later during baking. To avoid handling condensate or re-evolvement of fume, it is preferable to destroy the fume at the source, in one step. Tests carried out with a pilot catalytic reactor show that pitch mel ter fume can be incinerated at a catalyst inlet temperature as low as 3lSoC.
mass-spectrometric intensities) is inadequate. Through the use of equipment and techniques designed to accomplish two or posSibly three of these modes simultaneously, a more complete, quantitative characterization of multicomponent systems can be determined. The details of the design are described and measurements are presented to illustrate the precision and versatility attainable. Applications to the following are discussed: (1) precise determination of entropies and entropies of sublimation, (2) measurement of diffusion limited sublimation, and (3) determination of phase diagrams. *Based on work performed under U.S. Atomic Energy Commission and U.S. Department of Energy contract no. W-3L-L09-ENG-38.
(2,50 p.m.)
COMPARISONS AND INTERRELATIONS FOR FOUR METHODS OF VAPOR PRESSURE
MEASUREMENTS AT HIGH TEMPERATURES, P. G. Wahlbeck, Department of Chemistry, Wichita State University, Wichita, KS 67208. Four methods of measuring vapor pressures at high temperatures will be compared, and relationships between the methods will be discussed. The methocr1s are: Knudsen effusion, detection limit < P <2 Pa~ Isotropy failure, 2 Pa < P < 27'S Paj Ruff-MKW, 600 Pa < P < apparatus limit: Transpiration, detection limit < P < apparatus limit. (1 torr = 133.322 Pal "Detection limit" refers to the analytical senSitivity to detect the transport of sample. "Apparatus limit" refers to the greatest pressure usable in the apparatus. By using the methods in conjunction with one another, the entire accessible region of vapor pressures may be measured. The methods are interrelated with each other through the flow characteristics of the pressure regimesj i.e., molecular flow for the Knudsen method, the transition region between molecular and hydrodynamic flows for the Isotropy failure method, and hydrodynamic flow for the Ruff-MKW and Transpiration methods. CUrrent and past research regarding the validities of the methods will be presented and discussed.
(4,30 p.m.)
EQUILIBRIUM CAPACITY OF ALUMINAS USED IN DRY SCRUBBING, A. Tokerud, Flakt, A. Jebsens, Central Institute of Industrial Research
HF
NO ABSTRACT AVAILABLE
EXPERIMENTAL TECHNIQUES IN HIGH fEMPERA TURE SCIENCE V ISvonsored by the Thermodynamic Data Committee, Materials Science Division, American Society jor Metals l'um:sday, March 5,1986 Mardi Gras F-G Marriott Hotel ,nGlrman: R. A. Schiffman, Midwest Research Institute, City, Missouri 64110 Chair: P. K. Schenck, National Bureau of Standards, burg, MD 20899
(3,15 p.m.)
TENSIMETRIC METHOD TO INVESTIGATE THERMODYNAMICS OF POTASSIUM PHOSPHIDES: H.S. Marek, Stauffer Chemical Co., Elmsford, NY, R.A. Schiffman, Midwest Research Institute, Kansas City, MO. A tensimetric apparatus is described as an experimental technique for high temperature vapor pressure measurements. This apparatus, consists of a quartz Bourdon spoon-type gauge used as a null point instrument and controllers to monitor pressure-temperature. The investigations were performed in the range from 1 to lOOOTorr and 25 to IDOO'C. The potassium-phosphorus system was studied using this technique. From the experimental vapor pressure data standard enthalpy and entropy of the formation of the potassium phosphide compounds were calculated. The thermal stability of the potassium phosphides and the various crystalline modifications of red phosphorus are compared. The contribution of K-P bonds to the thermal stability of potassium phosphides is discussed. In addition, the kinetics of dissociation and vaporization of potassium phosphides and red crystall ine phosphorus are compared based on analysis of tensimetric data.
(3:40 p.m.)
Break
(4:00 p.mo)
OF REFRACTORY SOLIDS BY K.
Yagnik, D. R. Olander, University of
CA 94720.
vaporization of refractory materials is numerous areas of technology. This phenomenon is in an experiment utilizing a Nd-glass laser as a millisecond pulsed heat source. The targets of solid are held in a vacuum and can be rapidly heated to peak temperatures of 4500 K, as measured by a fast optical pyrometer. The pulse of vapor species from the laser-heated solid is detected in-flight by a quadrupole mass spectrometer. This signal, together with the measured surface temperature transient, can be used to deduce the vapor pressure of the solid by application of the Hertz-Langmuir vacuum vaporization equation. Partial vapor pressures of solids with multiple gas species can also be determined. System calibration is a major concern; the pyrometer must be calibrated to temperatures well above the range of available standards, and the mass spectrometer needs to be calibrated to detect signals equivalent to instantaneous pressures exceeding 1 atm. Application of the system to vaporization of uranium dioxide is described.
(2,25 p.m.)
SIMULTANEOUS EFFUSION MODES FOR SUBLIMATION MEASURMENTS*, J. R. McCreary and R. J. Thorn, Chemistry and Materials Science~ Technology Divisions, Argonne National Laboratory. For the determination of the thermodynamic properties of mult icomponent systems at high temperatures t the effusion technique in the single modes (mass or momentum effusion or
APPLICATION OF AN ATMOSPHERIC PRESSURE MASS SPECTROMETER SAMPLING SYSTEM TO CHLORINATION REACTIONS: N. S. Jacobson, NASA Lewis Research Center, Cleveland, Ohio 44135. An atmospheric pressure mass spectrometer system is based on the free jet expansion of a molecular beam through a series of differentially pumped vacuum chambers to a mass fil ter. This enables the volatile species from a one-atmosphere chemical process to be directly identified with the mass filter which operates at '\..10- 8 torr. Such a system is ideally suited to study chlorination reactions which involve the formation of volatile metal halides. Examples for both pure metal and alloy systems are discussed and the mass spectrometer data is correlatcu with kinet ic and morphological d.ata.
(4,25 p.rn o
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MOLEOJLAR BEAM MASS SPECfRCXVIETRIC MEASUREMENT Of UNSTABLE SPECIES IN SYSTEMS AT HIGH TEMPERATURES AND ATMOSPHERIC AND SUPERATMOSPHERIC PRESSURES: F. T. Greene, David A. Robaugh, and J. E. O'Donnell, Midwest Research Institute, Kansas City, MO.
Molecular beam mass spectrometric sampling and data acquisition techniques were developed to measure unstable species in transient systems at high temperatures and pressures. Unstable species were measured in a variety of experiments, which ranged from laser pyrolysis of stable and energetic materials to combustion of isolated coal particles. The apparatus will be described and its uses illustrated by selected results.
(4:50 p.m.)
HIGH TEMPERATURE KINETIC VAPORIZATION COEFFICIENTS OF INDIVIDUAL
TMS Annual Meeting 107 transition is closure related and not directly related to the interaction of the cyclic plastiC zone with the Widmanstatten packets as proposed by other investigators.
SPECIES: Paul W. Gilles and John Y .-K. Huang~ Department of Chemistry. University of Kansas, Lawrence, KS 66045, and J. Edward Bennett, Arkansas State University. P.O. Box 419, State University, AR 72467. The combined data from four types of experiments yield vaporization coefficients and absolute pressures of several individual species arising in a congruent vaporization process. The exper-
iments are a mass spectrometric Knudsen vaporization, a masS spectrometric Langmuir vaporization, a vacuum balance Knudsen vapor izat ion. and a vaccum balance Langmu ir vapor izat ion. The technique is illustrated by a study of the vaporization of selenium.
FATIGUE
TMS-AIME General Abstract Session Wednesday, March 5,1986 Mardi Gras C 2:00p.m. Marriott Hotel Session Chairman: T. P. Gabb, NASA Lewis Research Center, Mail Stop 49-3,21000 Brookpark Rd., Cleveland, OH 44135
(3:00 p.m.) FATIGUE BEHAVIOR OF A NiCoCrAlY COATING MATERIAL AT ELEVATED TEMPERATURES: J. Gayda, T. P. Gabb, and R. V. Miner, NASA Lewis Research Center, eve1 and, OH 44135.
cl
Single crystal nickel base superalloys employed in turbine blade app1 ications are often uti1 ized with a plasma sprayed coating for oxidation and hot corrosion resistance. These coatings may also affect fatigue life. As part of a larger program to understand the fatigue behavior of coated single crystals, fully reversed, total strain controlled fatigue tests were run on a bulk plasma sprayed NiCoCrAlY coating, PWA276, at 0.1 Hz. Fatigue data were generated at a lower temperature, 650 0 C, where the coating material has modest ductil ity and a higher temperature, 1050 0 C, where the coating materi ali s extremely ductile, showing tensile elongation in excess of 100%. Fatigue life and hardening behavior will be discussed and related to the failure process observed at each tempera ture.
(3:20 p.m.) TEM OBSERVATIONS OF CYCLIC DEFORMATION IN FULLY PEARLITIC
(2:00 p.m.) INTRINSIC AND EXTRINSIC FATIGUE RESISTANCE OF DUAL-PHASE STEELS:* J. K. Shang, J.-L. Tzou and R. O. Ritchie, Uni versity of California, Berkeley, CA 94720. The role of duplex ferritic/martensitic microstructures in influencing both fatigue crack initiation and growth has been studied in dual-phase AISI 1008 and 1015 steels. By varying the volume fraction and carbon content of the martensite, it is found that structures with highest resistance to "long" crack growth have lowest resistance to crack initiation (i.e., lowest fatigue 1 imits) and to "short" crack growth. Such observations are related to the generation of crack shielding mechanisms, e.g., crack deflection and closure, in duplex microstructures, which provide an efficient retarding influence for the growth of long cracks but play little role in influencing crack initiation or the behavior of "short" cracks with 1 imited wake. *Supported by the Office of Basic Energy Sciences, U.S. Department of Energy under Contract DE-AC03-76SF00098.
(2:20 p.m.) EFFECTS OF COMPOSITION AND TEMPERATURE ON FATIGUE OF Fe3A1:
STEEL: M. Dollar, M.A. Daeubler, I.M. Bernstein, A.W. Thompson, Metallurgical Engineering and Materials Science, Carnegie-Mellon University, Pittsburgh, PA 15213. Transmission electron microscopY of cyclically deformed fully pearlitic 1080 steel was carried out to understand fatigue behavior and surface fatigue crack growth. SpeCimens with fine and coarse interlamellar spacings were cyclically deformed at different stress amplitudes and number of cycles. It has been concluded that crack initiation observed along cementite lamellae is connected with the occurrence of an elevated density of dislocations at the interfaces. It has been also shown that lower relative resistance against crack initiation for fine pearlite was due to the higher efficiency of cementite-ferrite interfaces as dislocation sources in comparison with coarse pearlite. Theoretical aspects of the observations are discussed in terms of Ashby I s concept of deformation in plastically non-homogeneous materials.
(3:40 p.m.) ON THE DEVELOPMENT OF CRACK CLOSURE IN PHYSICALLY-SHORT FATIGUE CRACKS:* W. Yu and R. O. Ritchie, Department of Materials Science andMTnera1 Engineering, University of Cal ifornia, Berkeley, CA 94720.
S.J. ChO€i G.E. Fuchs and N.S. Stcleft, Materials Engineering Department, Rensselaer Polytechnic Institute, Troy, NY 12180-3590
High cycle fatigue experiments were performed on Fe-23.5a'j'..Al and Fe-27"'/oAl at 25°C, soooe and 60QoCj crack growth experiments were performed on Fe-27%Al and Fe-29i"Al at the same temperatures. Alloys were tested in either the 003 or partially B2 ordered conditions. Superior HeF properties were found in the D03 condition. Crack initiation always occurred at grain boundary triple points in HeF, while cleavage crack nucleation occurred in pre-notched crack growth samples. Fatigue crack growth rates were conSiderably higher than for other intermetallic compounds tested identically; B2 order provided lower growth rates at 25°C, but not at 500 0 C or 600°C relative to the D03 condition. The test results are explained in terms of the reported influence of composition and temperature on the degree of long range order and resul ting dis locat ion configurat ions. This research was supported by the US Office of Naval Research under Contract No. N00014-84-K-0276.
Stud i es have been performed on 2124 and 7150 a 1umi num alloys to document quantitatively the role of various "crack tip shielding mechanisms" in influencing the crack propagation behavior of long and physically-short cracks in the near- and sub-threshold growth rate regimes where conditions are nominal 1y ~K contra 11 ed. By compari ng the deve 1opment of crack closure, in particu1 ar, for long and short cracks in both coherent- and incoherent-particle hardened structures following wake removal, compression overload cycling and during ~K-increasing and Mdecreasing approach to the (long crack) threshold, the importance of crack closure in rationalizing the anomalous behavior of phYSically-short cracks is examined. *Supported by the Air Force Office of Scientific Research.
(4:00 p.m.) (2:40 p.m.) FRICTIONAL EFFECTS ON FATIGUE CRACK GRO,ITH IN BETA-AN~IEALED Ti-6Al-4V: T. S. Gross and S. Bose, Department of Metallurgical Engineering and Materials Science, University of Kentucky, Lexi ngton, KY 40506-0046 r~easurements
of crack tip heat generation in beta-annealed Ti6Al-4V indicate that the crack grm,th rate transition observed in this alloy is due to a transition from static friction induced 10ckin9 to sliding of the frac.ture surfaces under the influence of mode II crack tip displacements. The crack tip heat generation rate for this alloy was measured for R ratios (R ' 0min/omaxl of -0.1, 0.1, and 0.2. The heat generation rate above the slope transition for R ' 0.1 and -0.1 was an order of magnitude greater than the heat generation rate for R' 0.2. The closure stress was measured by a strain gage technique. The cases of R ' -0.1 and 0.1 are influenced by crack closure and the case of R ' 0.2 is not. Therefore, it has been concl uded that the crack growth
ULTRASONIC CHARACTERIZATION OF FATIGUE CRACKS':
O. Buck, R. B.
Thompson and D. K. Rehbein, Ames Laboratory, Iowa State Universi ty, Ames, IA 50011 The partial contact of two rough fatigue crack surfaces leads to transmission, reflection, diffraction, and mode conversion of an acoustic signal at those contacts. This paper discusses recent experimental and theoretical efforts to understand and quantify such contact on actual fatigue cracks in greater detail. It is shown that the size and denSity of individual contacts, or asperities, can be estimated from acoustic measurements. Furthermore, it is shown that this information is useful to provide the static stress across a partially closed crack as well as the "effective" stress intensity range which activates fatigue crack propagation.
* This work was supported by USDOE, Office of Basic Energy Sciences, Division of Materials SCiences, under contract No. W-74-5-Eng-82.
108 TMS Annual Meeting (4:20 p.m.) FATIGUE CRACK GROWTH AND LOW CYCLE FATIGUE RESPONSE OF TJMPEREU DUAL PHASF AISI 1015 AND MICROALLOYED HSLA STEELS: P. Deb, Materials Science Gr(JL,p, Naval Postgraduate School, ~ey, California 93943, USA, and M. C. Chaturvedi, The University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
The infI uenee of microstructure on the fatigue crack growth and low cycle fatigue response of two thermornechanically processed AlSI 1015 and microalloyed HSLA steels has been studied. For fatigue crack growth study, both the steels were deformed 33% (i.e., 8 roll passes) at 1023 and 1073 K respectively, followed by quenching in iced-brine solution while they were gi yen 66% (i. e., 12 roll passes) deformation at 1023 and 1073 K respectively, and subsequently quenched in iced-brine solution for strain-controlled low cycle fatigue study. These dual phase specimens were further annealed at 723, 823 and 923 K respectively for 1 hour. These annealed specimens were then used for fatigue crack growth and strain-controlled low cycle fatigue studies. Results of this study will be presented and discussed in greater detail.
(4:40 p.m.) ON ENHANCED FRACTURE TllUGHNESS IN 7075-T7351 AL ALLOY FOR SPACE SHUTTLE: G.R. Yoder, L.A. Cooley and T.W. Crooker, Naval Research Laboratory, Washington, DC 20375-5000, and T .J. Watson, Reynolds Aluminum Co., Richmond, VA 23261 In response to prel iminary concerns regarding the integrity of structural components for the Space Shuttle program, investigation was made of the cracking resistance of the 114 mm t hick plate materi a 1. Th is materi a 1 conta ins a number of macroand mi crostructural i nhomogeneiti es whi ch coul d be cl assed as defects or potential crack-l ike defects, viz. quite sizable stringers of brittle constituent particles, shrinkage cavities, and in one instance, a long line of spongelike porosity. Of particular interest, it was found that the fracture toughness s i gnifi cant ly exceeds handbook 1evel s. The reasons for thi s a pparent enhancement have been explored, and the tent at i ve c onc 1us i on reached that the enhancement may actually be attributable - at least in part, to the material inhomogeneities observed in the alloy. SEM fractographic evidence will be presented to support this contention, as well as the probable contribution of fatigue precrack morphology.
IN THE POTENTIOSTATIC PASSIVE CORROSION REGIME OF THE IRON-BASE SUPERALLOY A-286: M.A. Daeubler, K.H. Pries, C.W. Warren, I.M. Bernstein, A.W. Thompson, Carnegie-Mellon University, Dept. of Metallurgical Engineering and Materials Science, Pittsburgh, PA 15213. tests were conducted at 10 Hz, R=O.l under a passive n potential. When very underaged (VUA), the ordered y' by dislocations in contrast to highly overaged structures where Orowan looping was dominant. The slip band spacing smaller in overaged fatigue specimens. Surface cracks ("40\lm) were observed at 20% of life. Crack initiation generally occurred at slip steps which broke through the passive surface film, except' in ROA where inclusions initiated cracking. Since crack growth rates for both microstructures were not ifferent in corrosive environment compared to air, life was ontrolled mainly by crack initiation, Cracks initiated at usions reduced life time under passive corrosion conditions than cracks initiated in slip bands. work was supported by the Office of Basic Energy Sciences,
FORMING OF COATED AND CLAD MATERIALS II Sponsored by TMS Shaping and Forming Committee Wednesday, March 5,1986 Iberville 2:00p.m. Marriott Hotel Session Chairman: Henry Piehler, Department of Metallurgical Engineering and Materials Science, CarnegieMellon University, Pittsburgh, PA 15213
2:00 p.m.) CLAD METALS-AN OVERVIEW: Attleboro, MA 02703
J. Foster, Texas Instruments, Inc. ----
The use of cladding or coating a metal with another metal is a centuries old process and provides the engineer with a unique
tool to design a material with specific properties not found in an alloy or monometal. This paper reviews the techniques and processes used to produce a multilayer material and discusses some of the advantages of a clad metal system. Techniques, namely the rule of mixtures, have been used to analyze the behavior of a multilayer material based on the properties of the constitutive elements. However, as with monometals, fundamental mechani ca 1 property data do not descri be the formi ng cha racteristics of the material.Analytical solutions and techniques used to predict the formability of clad metals are reviewed and compared with available experimental data.A variety of products representative of a number of different forming processes are illustrated and discussed.
(2:30 p.m.) FORMABILITY OF ZINC COATED STEELS: R. W. Thompson, Inland Steel, East Chicago, IN and W. G. Brazier, Ford Motor Company, Allen Park, MI. Recent trends in the automotive industry have resulted in an increased usage of zinc coated steels. Because these coated steels have different surface topography and frictional characteristics compared to the bare cold rolled steels, there are important formability differences to consider. This study investigates some of the complex interactions occurring between coated steels, die materials and lubricants. Some results from prototype soft tool trials are discussed as well as the use of coated steels in full scale automotive production.
(3:00 p.m.) FRICTIONAL EFFECTS IN FORMING GALVANIZED STEELS: D. J. MEULEMAN AND S. P. KEELER. National Steel Product Application Center,
Livonia, HI Sheet steel formability depends upon the interaction of sheet surface, lubricant, and tool surface. Th is interaction assumes significant importance when comparing soft prototype and hard production tooling. Laboratory investigations simulated three primary forming modes: dome stretch ing, cup drawing, and draw bead sliding, Various electro and hot-dipped galvanized steels were evaluated on both hard and soft tools with several lubricants. The influence of the steel substrate properties was minimized through test design. or normalization of results, The frictional conditions were found to depend not only on steel coating, lubricant, and tool material, but also on the specific mode of deformation. In addition, some coating-substrate interaction was detected, particularly with less ductile zinc-iron coatings. In practice, some adjustment of frictional characteristics is possible with judicious selection of lubricant; different lubricants may be required for different types of coatings.
(3:30 p.m.) NECKING MODES IN CLAD MATERIALS, P.S. Steif, Dept. of Mech Eng., Carnegie-Mellon University, Pittsburgh, pA 15213. SyrnTletrically clad materials subjected to uniaxial, plane strain tension are studied theoretically. Employing a very general rate-independent constitutive model for each of the two different layer materials, we calculate the strains at which diffuse, necking-type defomation modes can emerge. Necking modes having a wavelength which is very long compared with both layers emerge first, just afte~ the maximum load. Such modes involve a periodic thinning or thickening of both layers. At higher strains, however, modes in which the core thickens and the cladding thins, or vice versa, are possible. These modes may be connected with the separation of the core and the cladding, a process which is observed to occur at strains considerably in excess of the maximum load, and whi ch may be connected with 1oca 1i zed necki ng and eventua 1 fa il ure. The i nfl uence of materi a 1 properti es and layer thicknesses on the necking process are assessed.
(4:00 p.m.) ROLLING TEXTURES DEVELOPED IN COMPACTS OF COPPER AND STEEL Herbert A. J. Chin, Pratt & Whitney, West Palm Beach, FL 33402 and Craig S. Hartley, Louisiana State University, Baton Rouge, LA, 70803 Deformation textures developed during cold rolling of copper-steel compacts were studied as a function of the degree of deformation for various configurations of the compact, volume fractions of core and different initial bonding conditions of the compact. Compacts having both copper clad on steel core and steel clad on copper core were subjected to reductions from 20-50% by rolling. Core volume fractions of 33% and 78% for the steel-clad copper and 33%, 47% and 78% for the copper-clad steel were investigated. Unclad material from the same stock was also rolled to the same schedules for comparison. In the case of the 33% volume fraction of core, both loose pack and hot isostatically pressed (HIP) initial pack configurations were studied. Results indicate that cladding of the steel with copper causes the deformation texture
in the core to develop at rather lower deformations that for the unclad material. At the highest deformation studied there was evidence of a shear texture developing in the steel core in addi tion to the conventiona 1 BCC roll ing texture. The texture development of steel clad on a copper core was similar to that of unclad steel except for a weak cube texture which began to appear at the highest deformations in the clad. Copper clad and core developed duplex textures consisting of a conventional rolling texture and a weak cube texture. These differences from the textures developed in unclad material are rationalized in terms of the alteration of the state of stress in the clad and core due to the cladding.
GENERAL PYROMETALLURGY I Sponsored by the TMS Pyrometallurgy Committee Wednesday, March 5,1986 La Galerie 1 2:00 p.m. Marriott Hotel Session Chairmen: W. J. Chen, Smelter Superintendent, Hidalgo SMelter, Phelps Dodge Corporation, Playas, New Mexico; and Barry Andrews, Conzinc Rio Tinto Australia, 55 Collins Street, Melbourne, Victoria 3001, Australia
(2:00 p.m.) THE TREATMENT OF METAL CONTAINING TOXIC SMELTER STOCK PILES IN THE CONTOP PROCESS: K. B. Chaudhuri, M. Koch, G. Melcher, KHD Humbo 1t Wedag AG, Ko 1n, Germany When smelt i ng copper matte from complex concentrates, fl ue dus ts are produced, the impurity contents of which may, depending on their respective levels in the concentrate, reach substantial heights. These flue dusts may be recycled if their quantities are sufficiently low or, if high, must be stockpiled to prevent the inevitable build up of impurities in the circuit when recycled.
TMS Annual Meeting 109 matte grade produced under commercially acceptabl e maximum particle temperatures. In this paper the distribution behaviors of the four minor el ements AS, SB, BI, and PB are reported. (3:15 p.m.) PROTECTION OF REFRACTORY BY HIGH SPEED BLOWING IN P-S CONVERTER: Takayoshi Kimura, Sei ichi Tsuyuguchi, Yasuo Ojima, Yutaka Ishii, Niihama Metallurgical Research Laboratory, Sumitomo Metal Mining Co., Ltd., 3-5-32, Nishibara-cho, Ni ihama-City, Japan To develop the high productivity converter, a 6 ton Peirce-Smith converter with 6 tuyeres was constructed. The apparent speed of blast and oxygen-enriched blast through tuyeres was tested from MACH number (M.N.) 0.3 to 2.5 range. An oxygen content in the blast was changed from 21 to 60 :t. At the speed rate of more than M. N. 1. 0, there is no tuyere blockage, so punch i ng is not needed, and mushrooms (accretion around the tip of tuyere) without disturbing of blowing is formed. By making good shape of mushrooms, the 1 i fe of refractory a round the tuyere zone becomes 3 times longer than that of normal blast speed. Mushrooms can be maintained during oxygen enri chment up to 40 % range. This high speed blowing technique caused the increase of splash from converter mouth but the oxygen efficiency was kept at a high level and the impurities such as Bi could be removed to the gas phase to the equivalent level which could be predict from thermodynamic equil ibrium calculation.
(3:40 p.m.) OPERATION OF THE NORANDA PROCESS AT DIFFERENT MATTE GRADES H. Persson, M. Iwanic, P.J. McKey, S. El-Barnachawy Noranda Mines Ltd., Point Claire, Quebec, Canada
Principal item in the process is the oxygen cyclone which allows to enrich individual elements in separate products by high volatilization rates, short retention time and optimum phase separation.
Since 1975, the Noranda process reactor at the Horne smelter has generally operated at matte grades of 70 - 74 % Cu. Tests were recently carried out to evaluate the performance of the reactor at lower matte grades. The test demonstrated the flexibil ity of the Noranda process to operate over a wide range of matte grades. The performance of the reactor at matte grades down to 55 % Cu was found to be as stable and predictable as at the higher matte grades. This paper presents the operating results of the test program including metallurgical data such as fuel and oxygen requirements, slag and matte characteristics and information on the deportment of minor elements.
Slag reduction lowers in the impurities in the slag to very low 1eve 1s. Coal, even of low qual i ty may be used as reductant and fuel.
(4:05 p.m.)
KHD's CONTOP Process offers a true a lterna t i ve to s tockpil i ng by cyclone smelting with oxygen and slag reduction by top blowing.
The transformation of the results from intensive pilot testing into an industrial plant of 25,000 t/a capacity yields a compact smelter of high flexibility at low investment and operating cost.
(2:25 p.m.) MINOR ELEMENT BEHAVIOUR IN FLASH CONVERTING: J. A. Asteljoki, Research Manager and S.M.I. Kyto, Research Meta 11 urgi st, Metall urgi ca 1 Research Center, Outokumpu Oy, Pori, Finland The Kennecott-Outokumpu Flash Converting is a new technique to convert copper matte into bl ister copper, util izing the proven Outokumpu flash smelting technology with very high oxygen enrichment. Pilot tests were successfully carried out in late 1984, the first results of which were presented at the AIME annual meeting in New York in 1985. Two types of matte with different impurity contents were tested. In this paper the distribution of minor elements at different operating conditions is presented. The results are compared with the corresponding behaviour of the minor el ements in Pei rce-Smith converti ng and primary fl ash smelting of copper concentrates. The economi cs of the fl ash convert i nQ process is also reviewed.
CORRELATIONS OF ELECTRICAL CONDUCTIVITY TO SLAG COMPOSITION AND TEMPERATURE Q. Jiao and N. J. Themelis Henry Krumb School of Mines, Columbia University, New York, N.Y.
The electrical conductivity of slags is an important factor in the design of electric smelting furnaces. Although there are many experimental studies on this subject, there are not as yet available quantitative correlations of conductivity to slag composi and temperature. The objective of this work was to develop correlations on the basis of the experimental data by various authors. The results are as follows: In the concentration range of industrial-type Si0 2 -CaO-MgO-MnO slags, where Si0 2 is assumed to exist mainly in the form of Si0 (4-) and the basic oxides are in the forms of Ca++, Mg++ and Mn++,4 respectively, the slag conductivity can be expressed as a linear function of the molar concentrations of the basic oxides. In the concentrat i on range of i ndustri a 1 non-ferrous slags, where the iron oxide content is over 20 %, the slag conductivity can be expressed as a logarithmic function of the molar concentrations of the iron and the basic oxides. The effect of temperature on slag conductivity, in the industrial range of interest, can be accounted by means of an arrhenius-type of function. The deviation of the many experimental data used from the correlations developed in this study is in the order of plus or minus 20 S.
(4:30 p.m.) (2:50 p.m.) MATHEMATICAL MODELING OF MINOR ELEMENT BEHAVIOR IN A FLASH SMELTING FURNACE: H. Y. Sohn, P. C. Chaubal, University of Utah, Salt Lake City, Utah, and L. H. Bailey, Kerr-McGee Corporation, Oklahoma City, OK A mathematical model has been developed to study the distribution behaviour of T1)inor elements in a flash smeltinq furnace. The model has been formulated based on both kinetic and thermodynamic considerations. The volatization of minor elements is considered to be mass-transport controlled, the driving force being the equilibrium partial press of various minor element species. Thermodynamic considerations in conjunction with mechanical suspension determine the distribution between various phases in the molten bath. The model has been used to study the effect of oxygen enrichment in the process air and the final
FORMATION AND CORROSION EFFECT OF SULFUR TRIOXIDE IN COPPER SMELTING PROCESSES: R. Backman and M. Hupa, Abo Akadel'1i, Turku, Finland, and J. Makinen, Plant Metallurgist of Copper and Nickel Smelters, Outokumpu Oy, Harjavalta, Finland The formation of sulfur trioxide in the gas line of a smelt in 9 furnace is an important factor, which must be taken into account in the design and operation of a smelting process. Sulfur trioxide participates in the formation of sulfates and sulfuric acid in the waste heat boiler and subsequent gas 1 ine, which may generate bu il d-up and carras i on problems. In this paper results of thermodynamic calculations and practical measurements from the waste heat boiler of the Harjavalta Copper Fl ash Sme lter are presented. Two different methods were app 1 i ed for
110 TMS Annual Meeting the SO, determination: chemical analysis and dew point method. The corrosion rate was detected below and above the dew point of sulfuric acid. The results indicate that a considerable portion of SO, is formed al ready before the waste heat boiler by a homogenous gas phase reaction.
(4:55 p.m.) DISTRIBUTION OF Zn, Pb, As, Sb AND Bi BETWEEN SLAG AND MATTE IN LABORATORY SCALE COPPER SMELTING Asmo Y. Vartiainen, Outokumpu Oy, Finland Jorg Steinhauser, Technical University of Berlin, West Germany Lauri E.K. Holappa, Helsinki University of Technology, Finland The behaviour of impurities in copper smelting was studied using a comp 1ex copper concentra te as feed materi ali n 1aboratory sca 1e particle jet smelting technique. The results are discussed. Using distribution coefficients of impurities between slag and matte phases as a function of matte grade, the obtained results are compared with equil ibrium values from the 1 iterature and with industrial values of modern copper smelting processes such as Outokumpu, Mitsubi shi, and Con top .
(2:30 p.m.) HIGH RESOLUTION IMAGING OF ION IMPLANTATION DAMAGE AND CHANNELING EFFECTS IN SEMICONDUCTORS: J. Narayan, Microelectronics Center of North Carolina, Research Triangle Park, NC 27709 and Materials Engineering Department, North Carolina State University, Raleigh, NC 27695-7907. Atomic structure of collision cascades was investigated by highresolution rEM, and accumulation of damage was studied using both TEM and Rutherford backscattering techniques. The formation of subcascades or bunching of the primary cascades was clearly observed for heavy ion implants. The central regions of the cascades were found to be amorphous with a high density of disorder in the surrounding regions. The cr~3ical ~~mage energy for amorphization was determined to be 6.0xlO eV em in silicon, which was found to scale with displacement threshold energy for other semiconductors. The experimental results on damage and dopant profiles are compared with theoretical calculations using the computer program }"..ARLOWE (Version-12). Ion channeling effects result in reduction of damage peak and deep penetrating profiles. Methods to control damage and dopant profiles and channeling effects are discussed.
(3:00 p.m.) Z-CONTRAST IMAGI NG AND ELECTRON CHANNELl NG ANAL YS I S OF DOPANTS IN SEMICONDUCTORS*, S. J. Pennycook, Solid State Division, Oak Ridge National Laboratory, Oak Rldge, TN 37831.
(5:20 p.m.) DISTRIBUTION OF MINOR ELEMENTS IN NICKEL MATTE SMELTING R.S. Celmer and J. M. Toguri, University of Toronto, Canada
Toronto,
The distribution of several minor elements between iron sil icate slags and copper-ni cke 1 mattes was determi ned at 1250 degrees C. Samples were equilibrated in an atmosphere containing 1 % SOz' or in a gas mixture which established a constant Poz and Psz ' Distribution ratios for Au, Co, Sb, As, Pb, Bi as well as Cu and Ni are given as a function of matte grade for matte Cu:Ni ratios of 9, 1, and O. The saturation behaviour of several of these elements in matte and slag is presented. Data are also given to show the effects of slag composition and metal-sulfur ratio in matte.
A Z-contrast image of dopant distributions in silicon can be obtained by detecting elastically scattered electrons on a scanning transmission electron microscope. The image is complementary to conventional diffraction contrast and high resolution structure images, and provides a quantitative, two-dimensional, elemental map at a spatial resolution determined by the probe size. Maps can be obtained in the time required for a single point x-ray analysis. At slightly reduced spatial resolution, axial electron channeling analysis can determine the dopant lattice location. The changes of the dopant and matrix characteristic x-ray yields are measured between channel ing and random incident beam conditions. Delocalization effects cannot be neglected for a quantitative analysis, particularly at higher accelerating voltages. *Research sponsored by the Division of Materials Sciences, U.S, Department of Energy under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.
fhe results are compared with those reported for copper smelting, cons i dered in terms of equil i bri um models for the smelt i ng (3:30 p.m.) ELECTRON MICROSCOPY OF III-V DEVICE ~!ATERIALS: T. S. Kuan IBM Thomas J. Watson Research Center, Yorktown Heights J N. Y. 10598.
RESOLUTION TEM STUDIES OF ELECTRONIC ..,RIALS II: Sponsored by the TEM Chemistry and Physics oj Metals Committee Bacchus , MarcJ:i 5, 1986 Marriott Hotel Chairmen: S. M. Ohr, Solid State Division, Oak Ridge Laboratory, Oak Ridge, TN 37831; K. H. Lawrence Berkeley Laboratory, University of Berkeley, CA 94720
(2:00 p.m.) STRUCTURAL ANALYSIS: WHAT CAN BE DONE WITH ATOMIC RESOLUTION MICROSCOPY?: R. Gronsky, National Center for Electron Mi c roscopy, Materi a 1sand Mol ecu 1 ar Resea rch Di vi s i on, Lawrence Berkeley Laboratory, Berkeley, CA 94720. The advantages of structural analysis at atomic resolution can be exploited in most electronic materials due to the precision with which they are produced. For those samples which are isostructural along the beam direction and thin enough to lie within weak phase object contraints, atomic resolution microscopy gives a directly interpretable image of all atoms in the path of the incident electrons. Less confidence can be plpced in images of thicker samples, and for structural variations along the beam direction, interpretation is rarely achieved. These points are illustrated with experimental results from the Atomic Resolution Microscope (ARM) at Berkeley. Thi s work is supported by the Di rector, Offi ce of Energy Research, Office of Basic Energy Sciences, Materials Science Division of the U.S. Department of Energy under Contract No. DE-AC03-76SF00098.
New sophisticated III-V deVices, such as the modulation-doped field effect transistor (HODFET), are comprised of a thin multilayer material structure of AIGaAs and GaAs grown by either the molecular beam epitaxy (NBE) or the metal-organic vapor phase epitaxy (MOVPE) techniques. Recent high resolution electron microscope studies have shed new light on the nature of the AIGaAs alloy system and the stability of these III-V device structures. In AIGaAs layers grown under certain conditions a preferred long-range ordered state was found, which might represent the equilibrium state of the alloy at low temperature. Through high-resolution TEM and STEM analyses, structural features very important to dev ice performance and to process development and control, e.g. J the atomic abruptness of the AIGaAs/GaAs heterojunctions and the microstructures and thermal stabilities of various metal/GaAs contact interfaces, have also been studied. These activities, as well as their impact and future challenges, will be discussed.
(4:00 n.m.) A TEM STUDY OF DISLOCATION MOTION AND METAL-SILICIDE FORMATION IN S1: D. M. Vanderwalker, State University of New York at Stony Brook, Stony Brook, New York 11794. Transmission electron microscopy was used to study the motion of partial dislocations and the formation of metal-sll1cides on dislocations and twins in silicon. Single crystal Si was compressed and cooled under a high stress in order to examine the nucleation and propagation of kinks on partial dislocations. At 350°C, the structure initially in the stressed state was found to return to equilibrium in intrinsic Si. The relaxation temperature is lower in specimens containing metal impurities because the dislocation kink migration energy is reduced when the Si covalent bonds are weakened. In doped specimens, the kink formation energy can be reduced by the electrostatic interaction between charged dislocation and dopant. A dark-field TEM method was developed to determine the crystal structures of second phases based on the fact that the change in intensity is proportional to the difference in structure factor. The method was applied to identify the Cu and Ni silicides on twin boundaries.
TMS Annual Meeting 111
HYDROMET ALLURGICAL REACTOR DESIGN & KINETICS - VI Sponsored by TMS-AIME Hydromefallurgy, Physical Chemistry, and Electrolytic Processes, and SME-AIME . Chemical Processing Committees Wednesday,March 5,1986 La Galerie 6 2:00 p.m. Marriott Hotel Session Chairpersons:, Gary W. Warren, Department of Metallurgy and Materials Science, Carnegie-Mellon University, Pittsburgh, PA 15213; Paulette B. Altringer, Salt Lake City Research Center, U. S. Bureau of Mines, 729 Arapeen Drive, Salt Lake City, Utah 84108
(2,00 p.m.) EV~LU~TION
OF MASS TRANSFER COEFFICIENTS IN METAL DEPOSITION BY ELECTROCHEMICAL TECHNIQUES, T. J. O'Keefe, S. F. Chen, and J. S.
Cuzmar, Department of Metallurgical Engineering and Graduate Center for Materials Research, Un! verst ty of Missouri "Rolla,
undergone evolutionary change. Using copper refining and winning, as an example, the cells have undergone little change since the process was invented, 100 years ago. Most recently, dramatic changes have been proposed. This paper explains the design of the conventional cell, summarizes its drawbacks, and presents an overview of new technology. (4,00 p.m.)
PRECIPITATION PROCESSES IN HYDROMETALLURGY, L.
Laboratory and Department of University, Ames, IA 50011
Chemical
E. Burkhart, Ames
Engineering,
Iowa
State
In hydrometallurgical opera tions, prec ipi ta tion is often used as a means of separation and purification. The process goals are high
recovery.
high purity,
good
filterability
of
the
preCipi-
tate, and ease of handling of the product. These properties can be related in a fundamental way to the kinetics of the competing rate processes of nucleation, growth, ripening, aggregation, and coagula tion of the prec ipi ta te particles--phenomena which in turn are controllable by accessible process variables such as reactant concentration, reactant ratio, hydrodynamic design of the precipitation vessel, and selective use of complexing :'igents. Two examples are gillen from work being done at Iowa State on the recovery of uranium from in-situ leach liquors and on the precipitation of rare earth metals. In both cases, careful characterization of the precipitates by modern analytical techniques also played a major role in the successful design of the processes.
Rolla, MO 65401.
A modification of the tracer technique of Ettel et a1 has been developed for determining mass transfer coefficients in electro'" lyte for both electrowinning and electrorefining systems. The method inval yes fhe direct measurement of the limiting current dens! ty of a Ag tracer ion in copper sulfate electrolyte by cyclic Yoltammetry techniques. Additional tests were made by codeposi ting the tracer wi th copper to compare the resul ts of both methods. Rotating disc and vertical stationary cathodes were used. In order to determine the genera+~ validity of the technique, tests were also made using a Cd tracer in zinc sulfate electrolytes and the data indicated consistent, reasonable results could be obtained. The new method appears to be particularly useful 1n making rapid, cursory evaluations of mass transfer condi tions in an electrolytic cell.
(2:30 p.m.)
APPLICATION OF TRACER STUDIES IN DETERMINING MASS TRANSFER PROPERTIES DURING METAL DEPOSITION, T. J. O'Keefe, J. S. Cuzmar,
and S. F. Chen, Department of Metallurgical Engineering and Graduate Center for Materials Research, University of Missouri .... Rolla,
Rolla,
MO
65401,
and
V.
A.
Ettel,
IN CO
Ltd.,
(4:30 p_mQ)
REACTIONS AND POSSIBLE REACTOR FOR THE PRECIPITATION OF METAL SULFIDES USING THIOACETAHIDE; C. Nesbitt, R. Crowell, J. Hendrix, J. Nelson; Mackay School of Mines; UniverSity of Nevada, Reno;
Reno, Nevada
89557.
A study was conducted to test the effectiveness of using thioacetamide (TAA) to precipitate metals from waste water streams. The initial portion of the study determined the effects of temperature, pH, and concentration of TAA in the formation of filterable metal sulfide precipitates. Tests were conducted on actual waste streams, including two chloride leach washes and a sulfuric acid wash. In the tests conducted at 65°C, sulfide and oxide precipitates were successfully formed. Most metals, including arsenic. were removed within the 96 to 99 percent range; typically, 73 percent of the iron species were removed. From the data acquired from these tests, a reactor design for the handling of many types of solutions may be achieved. A jacketed constant stirred tank reactor, or batch reactor could be sized based on total feed rate of the streams treated. Filtration capacity may be calculated from the concentrations of the metal species in the solution.
Sheridan
Park, Mississauga, Ontario, Canada L5K 129. A combination of the voltammetry and codeposition techniques was used to evaluate mass transfer conditions during zinc and copper deposi tion. Initially, the mass transfer coefficient of the tracer ion was determined electrochemically by measuring its limiting current density. Next, a series of codepositions at various current densities was performed and the mass transfer coefficient was redetermined by chemically analyzing the deposit. The enhancement in the mass transfer coefficient of the tracer that resulted from the increased natural convection or mixing due to metal deposition and/or simultaneous gas evolution was determined. The resulting effect of the improved interfacial mixing on the theoretical limiting current densities was calculated.
INTERFACES IN COMPOSITES III: Reactions Sponsored by the TMS-ASM Composite Committees Wednesday, March 5, 1986 2:00 p.m. Marriott Session Chairmen: Dr. Steven G. Fishman, Office of Nava Research, Arlington, VA 22217; and Dr. J. A. Massachusetts Institute of Technology, Cambridge, MA 021
(2:00 p,m.)
(3,00 p.m.)
FIBER-MATRIX REACTIONS IN SIC REINFORCED MODIFIED TI-6Al-4V: THE ELECTROWINNING OF DILUTE ZINC SULFATE SOLUTIONS IN A FLUIDIZED BED ELECTROCHEMICAL REACTOR, Richard Squillace and. Renato
G. Bautista, Dept. of Chemical & Metallurgical Engineering,Mackay School of Mines, University of Nevada Reno, Reno, Nevada 89557 A cylindrical fluidized bed electrochemical reactor was employed to electrowin dilute solutions of zinc ions in sulfuric acid. Reactor performance was determined by measur if',Q the current, voltage, and quantity of hydrogen gas evolved. A supportive, porous Vycor glass was used as the membrane to separa te the high acid anolyte and the low acid catholyte solutions. Changing the size of the membrane diameter varied the bed width between 1.4 and 2.2 cm. The highest current efficiency was obtained with the smallest bed width at only a slightly lowered current density. A low acid concentration was required for the efficient recovery of zinc at concentrations less than 10 gIl. An inert electrolyte, sodium sulfate, was added to improve the catholyte conductivity and current efficienty, resulting in lowered power consumption to about 10 kwhrlkg, with the optimum current efficiency between 35 to 50 percen t.
IN THE DESIGN OF ELECTROLYTIC REACTORS:
Two modifications of Ti-6Al-4V, viz. Ti-6Al-4V-2Ni and Ti-6Al-4V2Fe, are being studied as matrices in SiC (SCS-6) reinforced composites that can be consolidated at 815°C. The low consolidation temperature leads to a reduction in the extent of embrittling matrix-fiber reaction products, when compared to conventional Ti-6Al-4V/siC consolidated at 927°C. Previous work has shown that Ni does not enter into the fiber-matrix reaction products in Ti-6Al-4V-2Ni/SiC, and that the reaction products are the same as those observed in conventional Ti-6Al-4V/SiC: TiC and Ti S Si 3 • Ti-6AI-4V-2Ni has also been shown to exhibit improved tensile strength compared to Ti-6Al-4V/SiC, although Ti2Ni forms in the microstructure during cooling from the consolidation temperature. This talk will describe the fiber-matrix interactions in Ti-6Al-4V-2Fe/SCS-6 consolidated at 815°C and the tensile properties of the composite. Growth kinetics of reaction products in Ti-6Al-4V-2Ni/SiC at 815°C will also be presented.
(2:30 p.m.)
(3:30 p.m.)
ADVANCES
C. C. Rhodes and R. A. Spurling 9 Rockwell IntI. SciencE" Center, Thousand Oaks, Cali fornia.
~ Wes~,
Anaconda Minerals Company, P.O. Box 27007, Tucson, Arizona
85726
Electrolytic cells have been used since the invention of electricity. From these early beginnings electrolytic reactors have
INTERFACES AND FAILURE MECHANISMS IN Al-SiC COMPOSITES; S.R. Nutt, Center for Solid State Science, Arizona State University, Tempe, AZ 85287. Aluminum alloys reinforced with'SiC whiskers exhibit significantly higher strength and modulus compared to
112 TMS Annual Meeting unreinforced alloys. However, the fracture toughness of AI-SiC composites is poor, and fracture mechanisms are not well understood. In this study, high resolution and conventional TEM techniques have been used to analyze interface microstructure in 2124 and 6061 Al alloys reinforced with SiC whiskers. Composite specimens showed interfacial oxides which often formed a discrete layer 2-5nm wide along the whisker- matrix interface. Bulk tensile fracture specimens were sectioned to reveal highly deformed regions very near the fracture surface. Observations of near-surface microstructure in fractured specimens included (1) void nucleation at whisker ends, (2) interface decohesion involving the thin oxide layer, and (3) transverse cracks in whiskers. TEM results will be discussed in relation to composite failure mechanisms.
LEAD, ZINC AND TIN III: Processing Technology Sponsored by the TMS Lead, Zinc, Tin Committee Wednesday, March 5,1986 La Galerie 2 2:00 p.m. Marriott Hotel Session Chairman: R. David Prengaman, Vice President, Research & Development, RSR Corporation, 1111 W. Mockingbird Lane, Dallas, TX 75247
(2:00 p.m.) AUTOMATIC DROSS REMOVAL FROM LEAD REFINING KETTLES: W. R.D. Couper and Howard Forrest, Associated Lead Manufacturers, Cresent HO,use, Newcast le upon ~ Tyne, England NE99 ICE.
(3 :00 p.m.) MULTIPHASL BINARY INTERNLTALLIC DIFFUSION n' S'IAINLESS SHE!. FIBER REINFORCED ALUMINUM MATRIX 'COMPOSITeS: 1\.:_Jl~J!aJ2.t:., Indian Institute of Technology, Bombay. (Pres':'ntJy wiLl '."he Pennsylvania State University, Applied Research Lahoratory,
P.O. Box 30, State College, PA 16804) Crowth kinetics of binary intermetallic compounds at the f iberl matrix interfac.e have been studied in stainless steel fiber reinforced alumiow,\ matrix composite,<=; fabricated by the infil-
tration, squeeze casting, and P/M hot pressing techniques. I\s expected in most binary diffusion couples, more than one intermetallic compounds of the type Fe Al form at the interface. However, not all the iron-aluminiJe 1ntermetallic compounds possible as dictated by the binary phase diagram are present. This is primarily the result of the simultaneous growth and consumption of various product phases as the diffusion-controlled interfacial reaction progresses between the fiber and the matrix. The molar volume of each product phase and the interf.:1ce thickness are dependent on the processing temperature, time. and pressure. Optimization of these parameters le.:1ds to a desirable interfacial bond strength in the composi tes.
(3:30 p.m.)
Associated Lead Manufacturers Limited have developed and patented an improved method of automatic dross removal from lead refining. The system uses a specially designed machine which is capable of coping with all types of dry and semi-dry dross. The removal is fast and efficient leaving the lead surface virtually clear of dross. Hygiene improvements are possible due to the almost totally enclosed hooding arrangement. The first production sized prototype was put into fllil time operation at the Elswich works of Associated Lead Manufacturers in November, 1982. This machine proved to be very reliable in a hostile environment and has removed over 12,000 MT of dro'is to date. From this prototype stage further design improvements were incorporated in the seven drossing machines which now handle all the refining drosses produced in the Elswich works.
(2:30 p.m.) USE OF OXY-FUEL BURNERS IN SMELTING LEAD BATTERY SCRAP IN SHORT ROTARY FURNACES: Karl Friedrich Lamm, Blei-Und Silber Hutte, Braubach GMBH, Emser Strasse 11, 5423 Braubach, Federal Republic of Germany.
BREAK
The paper describes the oxy-fuel burner and its i.nstallation into rotary furnace used for smelting battery scrap. The Dxy-fuel burner has decreased fuel usage, increased production, decreased dust loss and recycle, and improved refractory life.
a short
UNDERSTANDING TUNGSTEN FIBER/MATRIX INTERFACE STABILITY IN TFRS COMPOSITES PART I: MATRIX VARIATIONS': T. Caulfield, .Y.P. Wu and J.K. Tien, Center for Strategic Materials, HKSM, lumbia University, New York, NY.
work on W-fiber reinforced superalloy composi tes a Ni-Fe-base matrix, Incoloy 903, has elucidated the 0 c i g~e~~bgoc~hase n~~ri~) d t~~O~~~p~;~~~;~s r~~g~ g~ i to enhance fiber/matrix compatibility in TFRS composites iber/matix interface, one must suppress the formation and of this interfacial reaction zone. One method to achieve
r6§6
,fg
entai i~e~i ~~~i~~m~~~~ ~~ I ~~~~~s~E t~~~t p~~~n~i~~ {~~~r p~~;~~~~~ron deals with correlating reaction zone growth kinetics with matrix chemistry, reaction zone chemistry and the local equi 1 i bri urn chemistry at the reaction zone/matrix interface for matrix composi tional variations excluding tungsten variations. The reaction zone and local equilibrium cj1emistries were obtained using calibrated, quantitative microprobe, EDS analysis across the three domains of the as-annealed composi te diffusion couples. Our studdies reveal that maintaining a ceiling level or maiximurn on the cumlative sum of the re, Co and Cr contents in the matrix results in a decrease in the reaction zone growth kinetics. This effect . ... .. ., phas e eq ... ~
1PffiTs
L
•
•
,
(3:00 p.m.) SODIUM METAL TREATMENT OF COPPER DROSS: Curtis Bates, Glover Lead Smelter, Asarco Inc, Glover, MO; and Carl Di Martini, General Supt., Central Research Laboratories, Asarco, South Plainfield, NJ 0708Q A new
patented process for recovering lead from rough copper dross by treating with sodium was implemented at Asarco' s Glover Smelter in 1979. The baSic metallurgical principles of the process are explained and current plant operating procedures and results described. The advantages of the sodium process, as compared to traditional dross treating in a reverberatory, and its possible application to treating complex lead blast furnace drosses are discussed.
•
wOrk-TSS~?gs~~~~r bih~h~o~f~~~~~1~s o~eb~~~~~ ~~~~~- and li.
(3:30 p.m.) NEW METHOD OF ALLOYING CALCIUM AND ALUMINUM INTO LEAD: R. David Prengaman, Vice President, Research & Development, RSR Corporation, 1111 W. Mockingbird Lane, Dallas, TX 75247.
(4:30 p.m.) UNDERSTANDING TUNGSTEN FIBER/MATRIX INTERFACE STABILITY IN TFRS COMPOSITES PART II: MATRIX TUNGSTEN VARIATIONS':
~~t~~Y;f;~l~KS~: Ycbi ug~i~n8nt ~~;s It~7' N~~ni~~k :o~y ~trategiC Part II of this presentation discusses the effect of W matrix additions on the kinetiCS and nature of fiber/matrix interfacial reaction zone growth, and the accompanying interdiffusion. The W alloying addition to the modified Incoloy 903 matrix was 16 at,", twice the solubility limit of W in a nickel matriX. This resulted in the precipi tat ion of a tungsten-rich ,u-phase in the matrix. The growth rate of the reaction zone was found to increase while the rate of tungsten fiber dissolution was found to decrease for the W-modified matrix TFRS composite as compared to those for the nominal Incoloy 903 TFRS composite. The appearent increase in the kinetics Which describe the reaction zone growth in the W-modified matrix composite is attributed to coarsening of the W-rich phase at the reqcton zone/matrix interface at the expense of the preCipitated ,u-~hase in the matrix. The decrease in the rate of fiber dissolutIon is attributeo to the suppression of interdiffusion between the fiber and matrix, as a result of the interfacial chemistry being closer to the local equilibrium chemistry at the fiber/matrix interface. Quantitative microprObe SEM-EDS analysis was done to verify the kinetic models.
;;~~~ ~~~~ h~G:3~gf8r~~d~~ ~~~ ~~~ft~;~~Ip Rgfeg~~~l~e~~~~a~~k and Robert Signorelli.
Lead calcium alloys have been used extenSively for the past ten years for the production of maintenance free battery grids. Elaborate methods have been developed to alloy the calcium into the lead and prevent subsequent oxidation and loss. Aluminum has been added to lead calcium alloys to retard oxidation and prevent loss of calcium. Traditional methods of alloying aluminum have resulted in poor recoveries and excessive temperature requirements. A new method has been developed utilizing a eutectic 73% Ca - 27% Al alloy to simultaneously alloy both calcium and aluminum into lead with minimal loss of either constituent.
(4:00 P.m.) TREATMENT OF LOW GRADE TIN CONCENTRATES IN A MODERN CYCLONE SMELTER: M. Koch and S. Wirosoedirdjo, KHD Humboldt Wedag AG, Postfach 91 0457, 05000 Koln 91, Federal Republic of Germany.
The treatment of low grade tin sulfide concentrate by applying a cyclone furnace combined with slag fuming- and an electric re-
TMS Annual Meeting 113 duct ion furnace is perhaps the worlds most unusual if not most innovative approach to producing tin metal. This process is installed in the low grade tin smelter (Baja Ley) at ENAF's Metallurgical Complex at Vinto, Bolivia. A brief description is given on the history of ENAF's metallurgical complex as well as the integrat ion of the new low grade into the existing high grade smelter. The cyclone process and the plant flow sheet are discribed in detail giving special attention to recent operating data as well as to the flexibility of the plant and to new process variants.
monoxide caused by the counter diffusion of carbon and oxygen during decarburization. These theoretical predictions are compared with experimental measurements obtained using droglets 2-3 mm in radius at temperatures ranging from 1600 to 2000 C under levitated conditions and with free fall. The agreement between the theoretically predicted and the experimentally measured limits for the onset of the carbon boil is very good.
(3:30 p.m.)
MODELING IN PROCESS METALLURGY III: HEAT TRANSFER AND CHEMICAL REACTIONS Sponsored by the TMS Physical Chemistry Comll1illee and the PTDIISS Wednesday, March 5,1986 Mardi Gras N 2:00 p.m. Marriott Hotel Session Chairmen: A. E. Morris, Dept. of Metallurgical Engr., University of Missouri-Rolla, Rolla, MO 65401; Y. Sahai, Dept. of Metallurgical Engr., The Ohio State University, 116 West 19th Ave., Columbus, OH 43210
The Effect of Externally Imposed Magnetic Fields on Forced Convection in Czochralski Crustalk Growing Systems: R. Cartwright and J. Szekely, Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge,
MA 02139 The imposition of magnetic fields has proven to be quite successful in improving the operation of the CZ crystal growing system. We shall present a convenient asymptotic statement of this problem, which allows us to draw useful conclusions r,?garding the effect of the magnetic field in affecting the relative thickness of the momentum, thermal and concentration boundary layers. The effect of the magnetic field in modifying the distribution coefficient is also discussed. W
(3:5C p.m.) (2:00 p.m.) A Mathematical Representation of Wheel Casting Processes: E. Gutierrez and J. Szekely, Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge,
MA 02139 A mathematical statement is presented of single wheel continuous casting processes. A key factor in modelling these opera'tions is to represent the position of the meniSCUS and the recirculating flow fields in the molten region. In the paper we shall consider a broad range of operating conditions, ranging from the production of very thin foil in rapid solidification systems to the casting of thin plate. By considering the computed results some general operational and design guidelines have been developed.
(2:20 p.m.) MODELING OF PUSHER TYPE ALUMINUM REHEATING FURNACES: Yogeshwar Sahai, Dept. of Metallurgical Engineering, The Ohio State UnlversTty, Columbus, Ohio 43210, and J. A. C1umpner, Covenant College, Lookout Mountain, TN, 37350. A modeling study of gas flow in a pusher type reheating furnace has shown the inefficiency of such furnaces. This study was made in a one-fourth scale plexiglas model of one section of the furnace. A mathematical model has been developed involving the solution of the turbulent Navier-Stokes equation to represent the flow of gases in such furnaces. Predicted flow fields are in good agreement wi th those experimentally measured. The flow of hot gas has been modi fied by the use of baffles to attain faster heating rates. Design of these modifications will be described. The hea t trans fer to the a 1 umi num ingots has a 1 so been ma thema tically modeled. The predicted rate of heating and temperature profiles will be presented. The relevance of these results in industrial furnaces will be discussed.
(2:40 p.m.)
COMPUTER SOFTWARE FOR CALCULATING COMPLEX CHEMICAL EQUILIBRIA IN PYROMETALLURGICAL PROCESSES. Arthur E. Morris and Harry Flynn. Depart.ent of Metallurgical Engineering, University of Missouri-Rolla. Rolla. MO 65401. Co.plex pyroaetal1urgical processes require the aid of a coaputer to calculate the amount of each phase and the activity of each ele.ent in the product .ixture. Four different general-purpose programs were evaluated with respect to their ability to handle roasting and saelting equilibria in coaplex systeas, in both steady-state and batch processing: Solgas.ix-PV, Theraodata. Shiapo-Goto. and F*A*C*T. The first three systeas are available on the UMR coaputer, while the '*A-C-T syatea is available by telephone connection to McGill University. The advantages and liaitatlons of each systea will be discussed in teras of ease of operation, cost, and applicabil i ty to systeas contalnlne nonldeal solutions.
14:10 p.m.) SUBMERGED LANCE SMELTING OF COMPLEX SULFIDE ORES. Harry Flynn and Arthur E. Morris, Department of Metallurgical Engineering, University of Missouri-Rolla. Rolla. MO 65401. An experimental program on slielting of copper concentrates and COMplex sulfides using a submerged lance technique has been conducted. The high temperature and the turbulent conditions in the bath promote rapid attainllent of equilibrium between the matte, slag and gas phases. The results were used to verify an equilibriua smelting 1I0del obtained from the Solgas .ix-PV computer program.
The Effect of Thermosolutal Convection on Heat Transfer and Solidification in a Binary Alloy System: M. Thompson and J. Szekely~ Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139
(4:30 p.m.)
Thermosolutal convection is necessarily present in most alloy solidification problems. In the paper a general formulation is presented of this problem, through the simultaneous statement of the appropriate conservation equations. In generating solutions particular attention is paid to stability criteria, brought about by the coupling between heat and mass transfer. The theoretical predictions {lre being tested against a low temperature physical model.
There are a number of gas-evolving compounds which are pneumatically injected deep into iron or steel for desu1phurization (e.g. magnesium, calcium carbonate, calcium and its alloys). This phenomenon was simulated with the injection of aluminum hydroxide and manganese carbonate into liquid lead. Thermal similarity criteria were developed on the basis the rates of heat supplied by a particular mechanism to the heat required for decomposition. Of the mechanisms considered: radiation to the particles, convection through the gas phase, and convection through the liquid metal, the latter was by far the most important. The particles and gas were injected directly adjacent to a transparent window so the flow pattern in the lead could be photographed, and it was seen that the gas release occurred as small bubbles a few centimeters from the lance. The bath cooling rate indicated that the extent of decomposition and particle-liquid contact were almost complete. In contrast, unreactive particles exhibit only 300, contact. Therefore gas evolution is an important mechanism for increasing partic1eliquid contact in refining operations.
(3:00 p.m.) Break
(3: 10 ~.m.) The Nucleation of CO Bubbles in Molten Iron-Carbon Drops Reacting with Oxidising Gases, N. EI-Kaddah* and D.G.C. Robertson** ; * Dept. ~t. Eng., The Univ. of Alabama Tuscaloosa, Ala 35486, Dept. Met. Eng., Univ. of Missouri-Rolla, Rolla, Mo 65401-0249
**
A theoretical representation has been developed for the supersaturation of molten iron drops with respect to carbon
Ihe ~lmu1ation of Gas Evolution During Submerged Powder Injection G.A. Irons, McMaster University, Hamilton, ON, Canada and L.R. 'Farias,HyL Research Centre, Monterrey, NL, Mexico
114 TMS Annual Meeting
OTHER LIGHT METALS Sponsored by The Light Metals Committee Wednesday, March 5,1986 Ponchartrain Ballroom C Sheraton Hotel 2:00 p.m. Session Chairman: J. Whisnant, Lithium Corporation of America, P.O. Box 795, Bessemer City, NC 28016
taken Ln situ during electrolysis. The electrolyte consists u! ll~~ MgC12, 65~~ NaCl., 18;~ KCl and 6;~ e3C12' Cells opeLltt.' .It a temperature of 750-C and current densities up to 2 A/crn 2 • Spectral information from all identifiable species is l'OrrI..'Lltl'd with cell operating conditions in an uttempt to undcr~;tCind till..' nature of such phenomena as metal fog, streamers, and Inelt coloration, al) of which arc observed in these laborCltory-sca}c cells.
(4:00 p.m.) COMPOSITE !\NODE MAGNESIUM REDUCTION TECHNOLOGY: J. C. Withers. 3770 Larrea Ln .• Tucson, AZ 85715; R. O. Loutfy, 4660 N. Medre. Tuc<;on, AT 85749"
(2:00 p.m.) MAGNESIUM; HOW IT CAN BE AS BTG AS ALUI1INUM: J.C. Agarwal, Charles ~i'!ers Associates, 200 Claredon St., Boston, MA 02116. Magnesiu," and a1uminurr have many attributes in common, such as abundant raw "material and energy intensity in production. However magnesium has not yet become a major metal. History of the development of magnesium industry would be briefly examined to present why magnesium has lagged behind. The future of magnesium, the highest structural metal, can be made briQht if several developments are successfully accomplished." The major new breakthroughs needed are in the areas of I) corrosion abatement, 2) new alloys development to take advantaqe of magnesium's properties, 3) utilization of fabrication technology suitable for magnesium-based alloys, 4) safe handling of magnesium. In addition, some business practices such as an efficient market for magnesium scrap would need to be developed.
All electrolytic magnesium is produced by electrolysis of MgCI, in chloride electrolytes. Attempts have been made to produce magnesium from the most economical magnesium compound, MgO.
The MgO is not sufficiently soluble in known fused salts at reasonable operating temperatures to sustain a practical current density without anode effect. Composite MgO-C anodes have been investigated in ct1loride electrolytes. but chlorine evolved at the anode. A new process has been patented to utilize MgO-C anodes in mixed chloride-fluoride or all fluoride electrolytes that efficiently produce electrolytic magnesium at about 700°C with only CO ,ICO as an anode gas. The process has been demonstrated on a laboratory scale with the production of magnesium at less than 4 kWh/lb. It is projected that the composite magnesium anode process can produce magnesium at about 1.2 to 1.3 times the Hall-Herault greenfield aluminum production cost.
Ex-
perimental details will be presented and the projections of commercial production cost will be discussed.
(4:30 p.m.) (2:30 p.m.) BERYLLIUM WITH IMPROVED DUCTILITY AND ISOTROPY: J. P. Denny, E. W. Filer, and R. C. Solbach, Cabot Corporation, P.O. Box 1296, Reading, PA 19603.
A past deterrent to wider applications of beryllium has been its inability to undergo plastic deformation at ambient temperature. Impact attritioning, followed by air classifica-
GALLIUM METAL: FUTURE WORKHORSE FOR ELECTRONICS? by F. Katrak, Charles Rivers Associates, 200 Claredon St., Boston, MA 02116. Many electrical engineers comment that gallium will advance the frontiers of electronics in the 1990s just as silicon did in 1960s. If this is true, the use of gallium would grow expontentially. This paper discusses the implications of such a demand growth of the gallium market. Price projections for gallium will be discussed on the basis of its cost of production from various mineralogical and geographic sources.
tion, is shown to yield beryllium powders with a high degree of cleanliness and low oxide content. Hot pressing of these powders yields consolidated bodies with a density in excess of 991. theoretical, and elongations significantly better than previous values of If.. Room temperature tensile elongations of hot pressed -400 mesh impact at tri tioned powder were 3.2 and 3.41. in longitudinal and transverse directions. These powders may also be isopressed prior to hot pressing. This procedure yields hot pressed bodies which have excellent isotropy, as determined by coefficient of expansion measureusing a vacuum laser dilatometer in three orthogonal ons of the hot pressed billet. The coefficient of on variation was less than ±2f..
PRESSURE LEACHING OF A NEW MEXICO COMPLEX SPODUMENE ORE: H. Garcia, A.E. Torma, A. Block-Bolten and A.K. Singh. New Hexico Insti tute~Mining and Technology, Socorro ,1m. Lithium extraction from naturally occuring spodumene has been investigated, The extraction with sodium carbonate was done at varying temperatures in an conventional Parr pressurereactor. Prior to leaching the compact Slfa-spodumene was conted to a porous beta-structure at 960 C. After pressure leang the solid containing Li C0 was subjected to bicarbonation, 2 3 en lithium is solubilized in fonn of LiHcn . The leach para3 0 ters were varied between 0.1-0.34 mol dm- 3 Na C0 , 125-240 C, 3 and 10-50% pulp density at constant stirring rate. Optimum leach conditions were derived using experimental data and a statistical evaluation technique. Experiments carried out at the optimum conditions gave lithium extraction as high as 97.3%. In this process, the lithium extraction with respect to Na C0 concen2 3 tration was found to be first order. The activation energy an~l frequency factor have been determined as 33.4 kJ and 17.13 min respectively, It is suggested that the reaction mechanism involves the formation of an intermediate activated complex, the thermodynamic data of which have been determined.
(5:00 p.m.) FOAMED ULTRALIGHT REACTIVE METALS: POTENTIAL USE IN LARGE SCALE SPACE ENGINEERING by F.H. Cocks, Dept. of Mechanical Engineering and Material Sciences, Duke University, Durham, N.C. 27706 With the increasing possibility of large scale engineering projects in space, the question of the density, strength, and stiffness of the materials used in such projects becomes of greatly increased importance. In most current space engineering application, aluminum alloys are used. However, foamed ultralight reactive metals as, for example, foamed magnesium/lithium alloys offer the potential of up to fifty percent reduction of launch weight with no loss in final structural strength. A method for the preparation of beams and other structural shapes in orbit by means of a metal foaminq process is described together with an experimental payload expected to be launched in 1985 to test these concepts by producing foamed structural elements in space.
PHASE DIAGRAMS FOR ELECTRONIC MATERIALS-PROGRESS AND OPPORTUNITIES I Sponsored by ASM-MSD Alloy Phase Diagram Activity Wednesday, March 5,1986 Mardi Gras H Marriott Hotel 2:00 p.m. Session Chairman: Professor Austin Chang, Department of Metallurgical Engineering, University of Wisconsin, 1509 University Avenue, Madison, Wisconsin 53706
(2:00 p.m.) (3:30 p.m.)
I NTRODUCTORY COMMENTS:
RAJo1AN SCATTERING STUDIES OF MAGNES IUM ELECTROLYS IS: S. - Y. Yoon, J.H. Flint, C.J. Kipouros, and Donald R.. Sadow~, Dept. Hateri
(2:05 p.m.)
As part of a study of the causes of the loss of current efficiency in industrial magnesium cells, the characteristics uf laboratory-scale cells are being investigated by eJectrocilemical and spectroscopic techniques. Specifically, to determine the f{lctors that control the concentrations and spatial distributions of the various chemical species in the eel J. Raman spectra are
Robert A. Laud i se
COMPOUND SEMICONDUCTOR PHASE DIAGRAMS. K. J. Bachmann, Departments of Chemi stry and Materi a 1 s Engineeri ng, North Carolina State University. Raleigh, NC 27695. Knowledge of the pressure-temperature-composition relation is essential for the appropriate design of bulk crystal growth and epitaxial procedures used in the fabrication of solid state electronic devices. The phase diagrams of the 1Il0st
important IlI-V and II-VI systems are discussed with special emphasis on alloys that are utilized in modern optoelectronic device manufacturing. Also, an outlook is presented on more complex systems that have potential for future use. The relation between the optical and electrical transport properties and the homogeneity range of selected compounds wi 11 be cons i dered in deta il.
(2:45 p.m.) TERNARY PHASE DIAGRAMS IN SEMICONDUCTOR SYSTEMS, Robert Sinclair,
Robert Beyers and Ki Bum Kim, Dept. Materials Science and Engineering, Stanford University, Stanford, CA 94305 In the development of advanced integrated circuits, new materials combinations are sought which might yield improvements in device performance and reliability. The stability of particular combinations during high temperature processing is critical to the success of the design. In our work, we have used ternary phase diagrams to understand the stability or degradation of metallization layers during thermal treatments. The essential features of the diagramsi.e. the stable tie lines - are determined from available thermochemical data and, in the absence of reliable data, from relatively simple thin-film experiments. It has been our experience that the diagrams account for experimental observations of annealing in virtually all thin-film cases. Examples of this approach will he given for silicide formation, oxidation and nitridation and for the formation of stable metal contacts on GaAs and other compound semiconductors.
(3:25 p.m.) GIBBS PHASE RULE AND ITS APPLICATIONS: Y.K. Rao, Department of Materials Science and Engineering, University of Washington, Seattle, Washington. Gibbs phase rule, the cornerstone of equilibrium thermodynamics, can be fruitfully employed to determine the minimum degrees of freedom possessed by a system composed of many phases and constituents. The idea of lindependent constituents· or IGibbsian components I in a system is examined from several different viewpoints and gr.oundwork is laid for obtaining unambiguously the value of C, the number of components. It is shown that finding C is not all that obvious once we shift our attention from the much-quoted simple systems to the more widespread and practically important mUlti-phase, multi-component systems. The extended form of the Gibbs phase rule and its various applications (example. vapor phase epitaxy of III-V compounds) are considered in some detail.
(3:55 p.m.) EXPERIMENTAL THERMODYNAMIC EVIDENCE OF INSTABILITY DOMAIN IN THE Inl_xGaxAs COMPOUNDS: C. Chatillon, M. Tmar and I. Ansara. Laboratoire de Thermodynamique at Physico-Chimie Metallurgiques L.T.P.C.M. Domaine Universitaire, Saint-Martin-D'Here. FRANCE Calculat ions or opt imisat ions of thermodynamic funct ions from the high temperature phase diagram lead to the conclusion that a miscibility gap exists at room temperature in the solid phase Inl Ga As, but no experimental evidence has been established to -aat~. Conventional approach, as thermal cycles or transport by vapor phase and X-ray analysis were unsuccessful on ternary systems since the diffusion processes are extremely weak in III-V compounds. We have performed thermodynamic measurements for homogeneous mixtures Inl_xGaxAs. Calorimetric determinations show the enthalpy of mixing is positive, its value being close to the value deduced from phase diagram calculations. Partial vapor pressures obtained from high temperature mass spectrometry with rrultiple Knudsen cells lead directly to the activities of InAs and GaAs, the shapes of which reveal unstable domains from 0.4 to 0.8 GaAs molar fraction. Calculated stable and metastable ternary In-Ga-As phase diagrams are presented.
(4:25 p.m.) STANDARD STAlE SELEJ:TION AND CALCUIATION OF CCMPOUND SEMICONDucroR PHASE DIAGRAMS: K.M. Chang, T.L. Aselage and T.J. Anderson, Deparbment of Chemical Engineering, University of-Florida,
Gainesville, Fl 32611 The calculation of binary and multicanponent phase diagrams for o:::mpound semiconductors requires the selection of ccmponent standard states and the evaluation of chemical potential differences bet"",en these states. The standard state usually selected is the pure canp::ment in the same phase and at the t:emperature of interest. Four different rrethcds of calculating chemical potential differences for this standard state selection are presented, each requiring a different data base. With two of these methods, procedures for estimating solution model ~arameters fran phase diagram and thermochemical data is addressed. Finally, alternative standard state selections are considered, including an infinite dilution state for elerrents
TMS Annual Meeting 115 that are experimentally difficult to characterize (c.g., As and
PI.
PHASE STABILITY AND TRANSFORMATIONS Wednesday, March 5,1986 La Galerie 5 Marriott Hotel 2:00 p.m. Session Chairman: Roy A. Vandermeer, Code 6320, Naval Research Laboratory, Washington, DC 20375
(2:00 p.m.) ATOM PROBE FIELD-ION MICROSCOPY STUDIES OF COMPOSITION FLUCTUATIO~S IN FE-45% Cr ALLOY: P.P. Camus, 5.5. Brenner, N.K. Miller*, and W.A. Soffa, Department of Materials Science and Engineering, University of Pittsburgh, Pittsburgh~ PA 15261
Atom probe studies have been performed to study the mode, morphology, and kinetics of phase separat ion in an Fe-45! Cr alloy. Particular attention recently has been focused on the influence of the solution treatment temperature and composition flue tuat ions occurring above the misc i bi I i ty gap on the subsequent decomposition of alloys aged within the miscibility gap. The results of this investigation will be presented and analyzed in terms of modern theories of the unmixing process.
*Metals and Ceramics Division, Oak Ridge Nat ional Laboratory, Oak Ridge. TN
37831
(2:20p.m.) MICROSTRUCTURAL EVOLUTION IN CONSOLIDATED NICKEL-BASED METALLIC GLASS POWDERS: C. Persad, J. Becker, M. Schmerling and H.L. Marcus, Center for MS&E, The University of Texas, Austin, TX 78712 Microstructural evolution in METGLAS 7025 (Ni56.5Mo23.sFeIQBIQ) has been investigated. Amorphous powders, produced by pulverizing planar flow cast ribbon (Allied Corp.). were consolidated by a high energy rate technique" using a pulsed power source. Bulk specimens (50 mm dia. x 2-6 mm thick) were produced. These disks were sectioned and evaluated by optical metallography and scanning electron microscopy. Selected specimens were studied by transmission electron microscopy in order to locate regions in the bulk in which the first crystalline nuclei were developed. Analytical electron microscopy was employed in morphological and compositional analysis of the dispersed particles. Different heterogeneous crystall ine microstructures were observed to develop as a function of the specific energy input in consolidation. The scale of these microstructures was correlated with the measured mechanical properties. This research was supported by DARPA, under NADC # N6 2269-85-C-0222.
(2:40 p.m.) APPLICATION OF A SCALED PARTICLE MODEL TO LlQUlDS WITH
TETRAHEDRAL STRUCTURE: C. Urbain, C.N.R.S. Universit~ de Perpignan. F. 66025 Perp-i-g--;a-n-Ce-dex, France
The application of the scaled particle theory to water and two melted silicates gives estimates of their physical properties: thermal expansion, surface energy. isothermal compressibility. etc. Information is ohtained about their polymerization level. To obtain such resul ts the model must be suppl ied wi th two separate sets of data: one set consists of thermodynamic properties (rare gas solubilities) and the other. transport properties (viscosities). The results are presented and discussed in detai 1.
(3:00 p.m.) THE SHAPE MEMORY MECHANISM ASSOCIATED WITH R-PHASE TRANSITION IN Ti-Ni SINGLE CRYSTALS: S. Miyazaki and C. M. Wayman, Materials Research Laboratory, Universlty of Illinois, Urbana, IL 6180[. The rhombohedral phase (R-phase) transition occurs prior to the martensitic transformation in Ti-Ni alloys subjected to special thermomechanical treatments or to which certain terna,·y alloying elements have been added. The shape memory effect is associated with both the R-phase and martensitic transformations although the recoverable strain associated with the former is smaller than with the latter. Tensile tests were carried out using TiNi single crystals and in situ observations were made using a special optical microscope.---rour distinct variants of the Rphase were found, and these could be correlated with each other by twinning modes. Six twinning planes in each variant were determined using two-surface analysis and were found to consist of three {IIO) planes and three {IOO). By stressing the most preferential R-phase variant was formed from the remaining
116TMSAnnuai Meeting variants by twinning deformation. Rased on the results obtained the mechani sm of the shape memory associ ated with the R-phase transition in alloys of the Ti-Ni type has been clarified. (3:20 p.m.) EFFECT OF CONCENTRATION DEPENDENT PAIR INTERACTIONS ON ORDERDISORDER REACTIONS*: C. Si.9.li and J.M. Sanchez, Henry Krumb School of Mines, Columbia University, New York, N.Y. 10027, First principle calculation results indicate that, in general, effective pair interactions are concentration dependent. We investigate here the effect of such concentration dependence on order-disorder equilibrium and on the topology of the associated phase di agrams. To that effect, the tetrahedron approximati on of the Cluster Variation Method has been used. Within this approximation, first nearest neighbor pair interactions are used to mode 1 Short and Long Range Order in fcc soli d sol ut ions whereas first and second nearest neighbor pair interactions are taken into account in bcc soli d sol uti ons. Prototype phase diagrams correspondi ng to di fferent dependence on concentration will be presented and discussed. *This work was funded by the National Sci ence Foundation under grant #DMR-82-06195.
(3:40 p.m.) PHASE RELATIONSHIPS AND THERMAL STABILITY OF RAPID SOLIDIFICATION PROCESSED NIOBIUM ALLOYS CONTAINING TRANSITION METAL CARBIDES:' D. M. Bowden and J. E. O'Neal, McDonnell Douglas Research
Laboratories, P.O. Box 516, St.Louis, MO 63166 A series of rapidly solidified niobium alloys containing transi-
tion metal (Zr,Ti,Hf,Nb) carbide dispersoids has been produced by electron beam melting and splat quenching. Carbide phase morphologies include both spherical and needle-shaped dispersoids. Phases present in the as-solidIfied ribbons have been identified by use of electron microscopy, and the thermal stability of these phases at temperatures up to 120QoC has been evaluated.
*Research performed under the McDonnell Douglas Corporation Independent Research and Development program.
(4:00 p.m.) ULTRA FINE GRAINED STEEL OF ORDINARY C-MN CONTENT: Y. Matsumura, H. Yada R&D Laboratory-TIl, Nippon Steel Corp., 1-1-1, Edami-
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The deformation of a carbon steel at austenite temperatures accelerates austenite/ferrite transformation. Further study of the ffect revealed some new aspects. When the reduction is suffiiently large, austenite is transformed to ferrite during de forion (strain induced transformation) even at high temperatures • fraction transformed and the ferrite grain size depend on the ,. , ion temperature and the reduction amount. The lower temperature and the more strain result in the finer grain size and the more fraction transformed. The true strain to obtain more than 0.7 of the fraction at about Ar3 temperature is up to 1.0. Such large strain can be reallized in the continuous rolling:the strain accumulates because of short inter-pass time. The transformed ferrite gra'ins are extremely fine, smaller than 3~m(ASTM No. 13.5), showing a good combination of high strength and ductility. The fatigue strength of the steel is also excellent.
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OF REFRACTORY ELEMENTS ON THE PHASE IN NICKEL-BASE SUPERALLOYS: * gnoul, John K. Tien, Juan M. Sanchez, ~~~e~~~~~fN~e7Sb2~~umb School of Mines,
ecent experimental studies directed at understanding the
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three revealed interesting results. Mo has been found to be a more potent gamma-prime antiphase boundary (APB) strengthener than W, as determined by a comparison of tensile yield strengths in the high volume fraction gamma-prime alloys. In addi tion, quanti tati ve STEM-EDS analysis reveals that the ·Ta and Nb y'/y
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alloy understanding and future arlo y design. Experimental data is correlated with calculations obtained via the Cluster Varia-
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energies. Our recently developed theoretical models show that APB energies have a compositional dependence as well as a pOSitive temperature dependence. Further experimental research is being conducted on even higher volume -y' nickel-base superalloys of varying refractory element content to refine our CVM models. *lh1s work 15 sponsored by the Office of Naval Research under contract N00014-83-K-0223 and moni tared by Don Polk.
and ternary gamma-prime (Ll ) ordered alloys. Our calc41.ations indicate that ~) segregation to the APB takes place and ..u.) contrary to pr ior knowledge, long range order decreases appreciably near the APS. These two effects can become more pronounced at high temperatures which results in an increase of APB energies with increasing temperatures. Our results will be
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tions of these theoretical findings will alsO be discussed with respect to the cross-slip model for the posi ti ve temperature
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*This work was sponsored by the Office of Naval Research under contract N00014-83-K-0223 and monitored by Don Polk.
(5:00 p.m.) A MICROSTRUCTURAL STUDY OF CAST AND HIPED Al-Si ALLOYS:
Light microscopy, scanning electron microscoPY (SEM) and transmission electron microscopy (TEM) have been employed to characterize the microstructures of AI-51 alloys, both in the cast condition and after HIPing." Light microscopy and SEM have been used to document the reduction in casting porosity as a function of HIPing time and temperature. In addition, these two techniques have yielded quantitative information concerning the phase distributions (in particular the Si and 01 phases). Variations in volume fraction, number density etc. of the microconstituents as a function of HlPing have been documented. The stereological parameters which characterize the HlPed specimens have been compared with similar data collected from material which had been aged at the HIP temperature but in the absence of pressure. Dislocation distributions in the AI-rich matrix have been characterized using the TEM, and related to the flow mechanism during
HIPing.
PHASE TRANSFORMATIONS IN COPPER ALLOYS III: New Developments in Copper-Base Alloys Sponsored by the TMS Non-Ferrous Metals Committee and the TMSIASM-MSD Phase Transformation Committees Wednesday, March 5,1986 Mardi Gras I-J 2:00 p.m. Marriott Hotel Session Chairman: Dr. W. Raymond Cribb, Alloy Research and Development, Brush Wellman Inc., 17876 St. Clair Ave., Cleveland, OH 44110
(2:00 p.m.) RAPID SOLIDIFICATION OF HIGH CONDUCTIVITY COPPER ALLOYS: T. K. Glasgo~, R. W. Jech, and R. L. Dreshfield, NASA Lewis Research Center, Cleveland, OH 44135. Copper binary alloys with greater than equilibrium solubility amounts of the elements chromium, niobium, and zirconium were prepared by chill block melt spinning. High conductivity, high strength alloys are of interest for hydrogen/oxygen engine thrust chambers. CuCr and CuZr ribbon cast readily; CuNb formed discontinuous pieces. As observed by TEt1 both Cr and Nb bearing alloys exhibited fine intracellular preCipitates; the Cr precipitates showed a strong orientation relationship with the copper matrix, while the Nb preCipitates did not. Zr concentrated in intercell ul ar two phase regions of Cu-Zr samples . Determination of retained room temperature hardness after anneal showed Zr the most effective additive ·and Cr the least on an equiatomic basis.
(2:30 p.m.) DEVELOPMENT OF HIGH STRENGTH-HIGH CONDUCTIVITY Cu-Ni-Si-P ALLOY (PMC-I02) FOR SEMICONDUCTOR LEADFRAMES: Young G. Kim, Jae H.Han, and Tae Y. Seong, Dept. of Materials Sci. & Eng., Ko':ea Advanced Inst. of Sci. & Tech., Box 131, Chongryang, Seoul, Korea, In H. Ryu, Onsan Plant, Poongsan Metal Corp., Onsan. Kyoungnam. Korea. Copper alloy strips used for semiconductor leadframes to which silicon chips are bonded are required to possess high strength, good electrical (thermal) conductivity, and optimum elongation.
Cu-base alloys of Cu/O.I-2.0 Ni/O.l-0.4 Si/0.Ol-0.06P were investigated.
(4:40 p.m.) EQUILIBRIUM ANTIPHASE,BOUNDARIES IN L12 ORDERED ALLOYS: * ~t~~2~g¥ Loh, Juan M.· Sanchez, John K. Tien, Center for c~terials, Henry Krumb School of Mines, Columbia University, New York, NY 10027.
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and P. R. Howell, Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802.
The alloy composition (PMC 102) of
Cu/1.3Ni/O.3Si/O.03P exhibited very high strength (610 MPa) , good electrical conductivity (lACS 58% min.) and optimum elongation (6%) under spring hard condition. The alloy is strengthened by precipitation hardening, grain size refinement, and work hardening. Double aging peaks appeared during isothermal agings due to the formation of Ni Si and Ni)P 2 precipitates. This paper presents the effects of alloying elements and aging conditions on mechanical and electrical properties in the Cu-Ni-Si-P alloys.
TMS Annual Meeting 117 (3:00 p.m.) METASTABLE PRECIPITATION IN DILUTE Cu-Be ALLOYS CONTAINING COBALT: A. Guha, Brush Wellman Inc., Alloy Division, 17876 St. Cl air Ave~evel and, Ohio 44110 Metastable precipitation in three dilute Cu-Be alloys, Cu-0.31 wt.% Be-0.25 wt.% Co, Cu-0.30 wt.% Be-0.49 wt.% Co and binary Cu-0.30 wU Be, was studi ed by transmi ss ion el ectron microscopy and differential scanning calorimetry. Even though the binary alloy does not exhibit age hardening, a marked response to age hardening was evident due to the cobalt addition. A Jarge density of metastable precipitates was observed in the ternary alloys. The precipitates were stable at hi gher temperatures compared to those in the binary alloy. Reversion experiments in conjunction with transmission electron microscopy were conducted to determine the relative positions of the metastable solvus 1 ines in the cobalt-bearing alloys. It was shown that the addition of only about 0.25 wt.% cobalt shifts the GP zone solvus to higher temperatures. No significant changes were observed in the alloy containing about 0.49 wt.% cobalt, except that beryllium was depleted from copper, forming cobalt beryll ides.
(3:30 p.m.) THE EFFECT OF MICROSTRUCTURE ON PROPERTIES OF PRECIPITATION HARDENABLE C724: Y. Saleh, 803 Alps Road, Branford, CT 06405, J. F. Breedis, 15 Copper Kettle Road, Trumbull, CT 06611. The copper alloy, C724 (Cu-12Ni-2Al-0.2Mg) can be hardened through either discontinuous or continuous precipitation of (Ni, CU)3Al, depending upon the rate of cool ing used after the preceding solution heat treatment. The effect of these differing modes of precipitation on strength. formability. and resistance to stress relaxation will be discussed in terms of their microstructures. Discontinuous precipitation in this alloy. in contrast to the behavior found in other systems such as Cu-Ni-Sn and Cu-Be. is responsible for higher ductility compared to the continuous mode. As a consequence of the discontinuous precipitate morphology. stress relaxation resistance is, however, lower compared to the continuous mode. The role of Mg in the alloy is to improve stress relaxation resistance. and reasons for thi s behavi or wi 11 be revi ewed.
(4:00 p.m.) COPPER-BASED SHAPE MEMORY ALLOYS: T. W. Dueria and K. N. Mel ton, Raychem Corporation, 300 Constitutlon Drlve, enlo Park, CA 94025 As shape memory metals continue to emerge as a conrnercially viable technology, the copper-base alloys are maintaining their appeal as the only "low cost" option and as the only practical alloy family capable of high trans it ion temperature (over 100 oC). Still two critical problems remain: instability of the transition temperature and a ductility still insufficient for many applications. The instability problem is particularly critical if the high transition temperatures available in these alloys are to be utilized. The poor ductility appears to be more important in the low transition temperature alloys, and is due to a large elastic anisotropy. A great deal of work is being done to solve this problem via grain refinement. Progress towards understanding and solving both of these problems will be reviewed, along with a general discussion of the two major Cu-base memory alloy systems (Cu-In-Al and Cu-Al-Ni) and their propert i es •
(4:30 p.m.) PRECIPITATION SEQUENCE IN A CU-14% AL-4% NI SHAPE MEMORY ALLOY*: J. Singh. Haydn Chen and C. M. Wayman. Dept. of Meta 11 urgy and Mining Engineering, University of Illinois. Urbana. IL 61801. The precipitation sequence in a Cu-14% Al-4% Ni (wt %l shape memory alloy was studied by transmission electron diffraction and microscopy as well as X-ray microanalysis techniques. On aging thin foil specimen up to 550·C in the electron microscope, an asquenched sample having a mixture of 2H- and D03 type metastable structures transformed to the stable simple cubic Y2 phase at or above 450·C. During the growth of the Y2 phase. partitioning of Cu and Ni atoms takes place from the Y2-phase towards the matrix. After the equil i bri um condit i on was reached. phase separati on of the Y2-phase into a NiAl phase and a copper-rich solid solution occurred at about 550·C. O~ further aging between 500 and 550·C, precipitation of ",-phase was also observed in the Cu rich matrix. The ",-phase is rich in Ni and Cu atoms compared with the depleted matrix. The solvus line for the ",-phase was about 600·C. D03 domains reappeared in the depleted matrix during cooling from 550·C to room temperature. * Work supported by NSF DMR under account #83-16981.
PROCESS MINERALOGY APPLICATIONS OF CATHODOLUMINESCENCE MICROSCOPY Sponsored by the TMS-SME Process Mineralogy Committee Wednesday, March 5, 1986 La Galerie 3 2:00 p.m. Marriott Hotel Session Chairmen: Otto C. Kopp, Department of Geological Sciences, University of Tennessee, Knoxville, TN 37996-1410; Richard D. Hagni, Department of Geology and Geophysics, University of Missouri-Rolla, Rolla, MO 65401 (2:00 p.m.)
A COMPARISON OF ZONED CARBONATE GANGUE FR
A STUDY OF FLUID INCLUSIONS WITHIN CATHODOLUMINESCENT ZONES IN GANGUE DOLOMITES. VIBURNUM TREND PB-ZN DISTRICT, SOUTHEAST MISSOURI: Lanier Rowan, U.S. Geological Survey, Box 25046, Denver Federal Center, MS 912, Lakewood, CO 80225 IQ 1985 Robert Voss defined a cathodoluminescent microstratigraphy (CLM) in hydrothermal gangue dolomite which spans the ore mineral paragenesis, and correlated the CLM throughout the Viburnum Trend. Using the eLM, the author was able to date fluid inclusions in the dolomite with respect to main stages of mineralization. The CLM permits the individual inclusions studied to be associated with specific growth bands. Thus, the temperature and salinity evolution of the mineralizink': fluid may be traced throughout the paragenesis. Throughout the C fluid inclusion temperatures are remarkably constant (near 115· C) salinities range between 18 and 22 wt.96 NaCI equivalent. In addition. changes in the fluid chemistry related to ore deposition may be inferred from changes 1n the luminescent banding as well as from dissolution textures. Finally, on the basis of the correlation of the CLM in dolomite, it is possible to extend the paleohydrologic system beyond the Viburnum Trend proper to the south and west.
(3:00 p.m.)
THE USE OF CATHODOLUMI NESCENCE MI CROSCOPY TO REVEAL HIDDEN CRYSTAL FACES IN GANGUE DOLOMITE CEMENTS. VIBURNUM TREND, SOUTHEASTERN MISSOURI, Jay M. Gregg, st. Joe Minerals Corp., P.O. Box SOD, Viburnum, MO 65566, Richard D. Hagni, Dept. of Geology and Geophysics, University of Missouri-Rolra, Rolla, MO 65401 Discordant cathodoluminescent banding has revealed the existence of complex (non-cleavage rhomb) dolomite crys ta 1 faces tha t developed during the growth of sparry gangue dolomite associated with Mississippi Valley-type sulfide orebOdies in the Viburnum Trend, southeastern Missouri. Subsequent stages of crystal growth, however, produced the rhombic crystal habit thus "hiding" the earlier complex faces. Rarely, the complex forms are expressed in the outward crystal morphology where the later stages of dolomite growth did not occur. The hidden crystal faces were indexed using universal stage microscopy. This kind of complex facet i ng has been observed where co-prec i pita t i on of dolomite and halite have occurred under strongly saline conditi ons. We be 1 i eve that the presence of trace meta 1sin the mineralizing brines were responsible for the complex faceting of dolomite in the Viburnum Trend.
(3:30 p.m.)
INTEGRATION OF CATHODOLUMINESCENCE AND GEOCHEMICAL APPROACHES IN STUDIES OF CARBONATE DIAGENESIS: Kyger C Lohmann Department of Geological, The University of Michigan,-Ann Arbor, MI ~8109
Diagenesis of carbonate materials results from interaction with water through processes of sol ution and preci pi tation. Wi thin each preci pi tated phase, a r-ecord of the temperature and
118 TMS Annual Meeting chemistry of the diagenetic fluid is preserved. However, most carbonates have undergone multiple episodes of such interaction and contain a complexly-mi xed chemi cal record. Cathodal uminescence microscopy (CL) provides a sensi ti ve, high resolution method for identifying both the number of diagenetic phases and the scale and fabric of their emplacement. Moreover, i t is possible to determine the spatial distribution of individual phases. For example, a single fluid may precipitate "constructi veil crystals in open pores while producing a "replaci veil intergr'owth in pre-existing rock components. Coupling of microscale sampling and geochemical analysis wi thin the framework provided by CL, provides a powerful tool for deconvoluting the complex chemical record of ancient cartxmates.
(4:00 p.m.)
WOHLERITE RECOGNITION BY CATHODOLUMINESCENCE: A.N. Mariano, 48 Page Brook Rd., Carlisle, MA 01741, P.L. Roeder, Dept. of Geol. SeL, Queen 1 s Univ., Kingston, Ontario K7L 3N6. The niobium-bearing mineral wohlerite [NaCaz {Zr,Nb)Si:l0s (O,OHF) 1 is generally considered to be rare and of very limited. occurrence in some agpaitic nepheline syenite complexes. In this study it is shown that wohlerite can be readily identified by cathodoluminescence (CL) and its occurrence is extended to ..i.jolitepyroxenites, carbonatites and silicocarbonatites. The diagnostic blue-green ltmlinescence allows it to be identified in rocks where it has apparently escaped recognition by investigators using routine petrographic techniques. In carbonatite programs Nb assays are often assumed to represent pyrochlore mineralization, but in the Prairie Lake carbonatite of Ontario, carbonatites and other alkaline rocks may, in selected areas t have their Nb contents almost exclusively from wohlerite. This work further demonstrates the value of CL as an effective means of enhancing the recognition of minerals in exploration and mineral processing programs.
(4:30 p.m.)
INDUSTRIAL APPLICATIONS OF CATHODOLUMINESCENCE Richard D. Hagni, Department of Geology and University of Mlssouri-Rolla, Rolla, MO 65401
MICROSCOPY, Geophysics,
CathOdoluminescence microscopy should be more fully utilized in applications to a wide range of industrial products. The study of mineralogy and textures or intergrowths of minerals can be grea t ly enhanced by the use of cathodo 1umi nescence mi croscopy in conjuntion wi th transmitted 1i ght, refl ected 1 i ght, and other icroscopic techniques. Important applications include the of bene,ficiation products, hydrothermal alteration lages, and refractories. Such studies allow the detection phases prev i ous ly overlooked, form a rapi d means for stinguishing cathodoluminescent phases from non-cathodominescent ones and between phases that cathodoluminesce in fferent colors, aid in the recognition of subtle textures thin single grains, and provide an excellent technique for ter determining the distributions of those phases that hodo luminesce. Cathodo 1umi nescence mi croscopy shoul d become standard item of equipment available in all process mineralogy laboratories.
SOLIDIFICATION TECHNOLOGY FOR ANIUM ALLOYS III: Alloy Development and High emperature Sponsored by the TMS Heat Treatment Committee IWednesday, March 5,1986 Mardi Gras D Marriott Hotel Chairmen: S. M. L. Sastry, McDonnell Douglas Research Laboratories, P.O. Box 516, Dept. 224, Building 110, St. Louis, MO 63166; D. Eyion, Metcut-Materials Research Group, P.O. Box 33511, Wright-Patterson AFB, OH 45433
(2:30 p.m.) CHARACTERIZATION OF A DISPERSION STRENGTHENED RAPIDLY SOLIDIFIED 1. F. Broderick, F. H. BETA-TITANIUM ALLOY, Ti-15V-6Al-2Er: Froes, Air Force Materials Laboratory, AFWAL/MLLS) WrightPatterson AFB, OH 45433; and J. A. Snide, University of Dayton, Graduate Materials Engineering, Kettering Lab 262, Dayton, OH 45469 An experimental metastable beta titanium alloy of composition Ti-15V-6Al-2Er was rapidly solidified, consolidated, and heat treated yielding an alloy strengthened by allotropic alphatitanium and Er203 dispersoids. Results from tensile tests at room temperature 425°C (800°F), 540°C (lOOO°F), and 650°C (1200°F), and creep tests at 425°C (800°F) /315MPa (30ksi), 540°C (lOOO°F) /2l0MPa (20ksi), and 650°C (l200°F) nOMPa (lOksi) are presented and compared to conventional titanium alloys. A TTT diagram, microhardness curves, and dispersoid coarsening data were developed by heat treating as-rapidly material at temperatures between 315°C (600°F) and 760°C (l400°F) for times up to 10 hours. The dispersoid coarsening data is compared to theory for the case of excess oxygen and that of excess erbium.
(2:55 p.m.) AARE-EARllI-DISPERSOID COI\RSENJN:i IN THE
6 PHASE AND a/6 PHASE
CF TI-SSN-4.5LA MM:!i.* Yoo-Dong Hahn am~. H. Whang, Department of Metallurgy am Materials Science, Polytechnic Institute of New York, 333 Jay street, Brooklyn, NY 11201 It has been shcMl that ,based on a systematic study on particle coarsening, rare earth dispersoids in 0 Ti alloys are very stable at elevated tenperatures. In order to study particle coarsening behavior in S and a /6 phases, rapidly q..tenched Ti-5Sn-4.5La alloy foils prepared from the melt were annealed isothennally in vacuum at the t~rature range of 850 -l,lOoOC. 'Ibe results show that a high coarsening rate occurs in the dispersoids at these temperatures, in contrast with the low coarsening rate in the a phase. 'Ibe high coarsening rate is attributed not only to high temperature , but also to the structural change in the matrix. 'ttIe results will be discussed along with those from previous studies in a Ti alloys.
--------------------------
* Research is sponsored by the Office of Naval Research
(3:30 p.m.)
BREAK
(3 :40 p.m.) RAPIDLY SOLIDIFIED TI ALWYS FOR HIG! TEM'ERAWRE APPLI-
CATIrnS.* S H Wbang Department of Metallurgy and Materials Science, Polytechnic Institute of New York, 333 Jay street, Brooklyn, NY 11201 The application of rapid solidification technologies to titanium alloy systems is relatively new am has become the subject of active research in recent years. In particular, research has been focused on alpha Ti alloys for high tenperature awlications. In the course of such research, many rare earth elements were added to titanium to create stable dispersoids at high teI1{leratures. Some results on microstructures and mechanical properties of these alloys containing rare earth indicate substantial improvements in these properties compared with those in the alloys containing silicon. 'Ibis paper will discuss various aspects of RS Ti research in terms of rapid solidification processing, microstructures and mechanical properties.
------------------
* Research is sponsored by the Office of Naval Research
(4:05 p.m.)
(2:00 p.m.) CHARACTERIZATION OF OXIDE DISPERSION IN RAPIDLY SOLIDIFIED TITANIUM ALLOYS: R. E. Anderson and J. L. Larson, Pratt Whitney Aircraft/GPD, West Palm Beach, FL 33402 Many studies have shown that rapidly solidified titanium alloys with rare earth elemental additions yield fine dispersions of rare earth oxides. These disperSions have potential for property enhancement in conventional as well as novel alloys. Rapidly solidified ~9wder was produced and characterized of conventional alloys with erbium additions. The particulate was screened to several size fractions and vacuum hot compacted. The resulting dispersions in each size fraction were evaluated according to average diameter, spacing, volume percent, and thermal stability.
SOLIDIFICATION STRUCTURE AND STABILITY IN RAPIDLY SOLIDIFIED MODEL ALLOYS OF Ti-Al-Zr-Er-B: R. G. Rowe, General Electric Corporate Research and Development Center, Schenectady, NY; T. F. Broderick, Air Force Materials Laboratory, AFWAL/MLLS, Wright-Patterson AFB, OH; E. F. Koch, General Electric Corporate Research and Development Center, Schenectady, NY; and F. H. Froes, Air Force Materials Laboratory, AFWAL/MLLS, WrightPatterson AFB, OH The microstructure of model alloys of Ti-6Al-6Zr with additions of Er and B reveals a duplex solidification structure of columnar solidification leading to equiaxed and dendritic structures near the top of melt spun and melt extracted alloys. The solidification structure was revealed by apparent boron segregation to cellular and interdendritic boundaries. Precipitation of needle-like TiB laths occurred adj acent to Er203 dispersoid particles.
TMS Annual Meeting 119 (4:30 p.m.) MECHANICAL CONTAINING
EVALUATION OF RAPIDLY SOLIDIFIED TITANIUM ALLOYS FINE DISPERSOIDS: M. F. X. Gigliotti, General
Electric Corporate Research and Development J Schenectady, NY; G. E. Wasielewski, General Electric Aircraft Engine Business
free anode polarization from the polarization with bubbles present. Experiments with a nickel anode evolving oxygen from aqueous alkaline solution indicate that this separation is possible.
Group, Evendale, OH; and R. G. Rowe, General Electric Corporate Research and Development, Schenectady, NY
Exploratory alpha titanium alloys containing various rare earth compound dispersoids were prepared by rapid solidification. The alloys were consolidated by HIP and extrusion and heat treated. The roles of matrix microstructure and dispersoid size and distribution were evaluated by comparing tensile and creep strengths of materials heat treated to different microstructures. Fundamental aspects of the role of matrix alloy chemistry were studied by comparing model alloys in which individual elements were systematically varied. Portions of this work were carried out under U. S. Air Force Contract No. F3361S-83-C-5034.
(4:55 p.m.) EFFECT OF Er, Si, AND W ADDITIONS ON POWDER METALLURGY CONVENTIONAL HIGH TEMPERATURE TITANIUM ALLOYS: R. G. Vogt, Air
Force Materials Laboratory, AFWAL/MLLS, Wright-Patterson AFB,. OH 45433; D. Eylon. Metcut-Materials Research Group, P.O. Box 33511, Wright-Patterson AFB, OH 45433; and F. H. Froes, Air Force Materials Laboratory J AFWAL/MLLS, Wright-Patterson AFB, OH 45433
In an effort to improve the high temperature capabilities of titanium alloys, Ti-6Al-2Sn-4Zr-2Mo and Ti-6Al-2Sn-4Zr-6Mo were strengthened by Er dispersoids, Si precipitates. and through the addition of W. These alloys were double melted. converted to plasma rotating electrode process (PREP) powder, and consolidated by extrusion. Results of tensile tests at room and elevated temperatures and creep tests at 480°C (900°F) /245MPa (35ksi)
and
S6SoC
(lOSO°F) /24SMPa
(35ksi)
of
heat
treated
conditions will be presented and compared to base alloys. Dispersoid coarsening characteristics at 925°C (1700°F) and l040°C (1900°F) will be compared. The potential for replacing conventional alloys with these newer alloys in high temperature applications will be discussed.
REDUCTION TECHNOLOGY VI: Chemistry Part B Sponsored by the TMS Light Metals Committee Wednesday,March 5,1986 Ponchartrain Ballroom D Sheraton Hotel 2:00 p.m. Session Chairman: Frank Baker, Section Head of Ceramics Division, Alcoa Technical Center, Alcoa Center, PA 15069
(2:50 p.m.) IN SITU RAMAN SPECTROSCOPIC INVESTIGATION OF MELT CHEMISTRY AND ELECTRODE PROCESSES IN LABORATORY-SCALE ALUMINUM CELLS:
S.-Y. Yoon, Y.Liu, J.H. Flint, G.J. Kipouros, and Donald K. Sadoway, Dept. Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge MA 02139. As part of a study of the causes of loss of current efficiency in industrial aluminum cells, the characteristics of laboratoryscale cells are being investigated by electrochemical and spectroscopic techniques. Specifically, to determine the factors that control the concentrations and spatial distributions of the various chemical species in both aluminum chloride and "Hall" cells, Raman spectra q.re taken in situ during electrolysis. Aluminum chloride cells with an electrolyte consisting of 5~~ AlC13' 53~~ NaCl, 42% LiCl have been operated at current densities up to 2 A/cm 2 . Spectral information from all identifiable species is correlated with cell operating conditions in an attempt to understand the nature of such phenomena as metal fog, streamers. melt coloration and anode effect, all of which are' observed in these laboratory-scale cells. Hall cell studies are in progress and results will be reported in conference.
(3: 15 p.m.) PRODUCTION OF HIGH PURITY METAL IN ALUMINUM CELLS : N. Toyama
K.Niwa, T.Taniwaki and K.Uchida, Sakaide plant, Ryoka, Light Metal Industries Ltd., Sannosu-I, Sakaide, Japan RLI began to produce 99.94 % ( Si: 330 ppm, Fe: 260 ppm ) potroom metal from 1981. In 1984, to produce higher puri ty potroom metal, red]Jction of impuri ties in anodes, alumina and bath had been studied. So the impuri ties in incoming materials became extremely low. And advanced computer control system which had already developed suppressed heat fluctuation and could keep pot condition constant. As a result, RLI produced over 900 tons of 99.97 % ( Si: 160 ppm, Fe: 80 ppm) potroom netal from November 1984 to April 1985.
(3:40 p.m.) EFFECT OF BATH ADDITIVES ON ALUHINUM METAL PURITY:
Ray D. Peterson and Alton T. Tabereaux, Reduction Laboratory, Reynolds Metals Company, P. O. Box 1200, Sheffield, Alabama 35660
(2:00 p.m.) A REFERENCE ELECTRODE FOR HALL CELL EXPERIMENTS : J. Burgman,
Carnegie-Hellon University, Dept. of Chemical Engineering, Schenley Park, Pittsburgh. Pennsylvania 15213; J. Leistra, Carnegie-Mellon University, Dept. of Chemical Engineering, Schenley Park, Pittsburgh, Pennsylvania 15213; Dr. P. Sides, Carnegie-Mellon University, Dept. of Chemical Engineering, Schen ley Park, Pi ttsburgh , Pennsylvania 15213 Two reference electrodes for use in cryolite-based melts have been developed and tested. In the "wetted molybdenum hook" deSign, aluminum wets a well-defined length of molybdenum wire in cryolite saturated with alumina. The hook design allows the immersion of a seal between the molybdenum lead and a protective sheath in the molten aluminum. In the "densified bath inverted design," aluminum floats above a cryolite mixture containing 30% barium flouride. The reference electrodes were compared to each other, to an aluminum pool, and to a molybdenum wire on which aluminum had been cathodicallY deposited. The wetted molybdenum hook electrodes, preferred by the authors. were found to be stable with .respect to each other within 5 mv for the eight hour testing period.
(2:25 p.m.) A
ROTATING CYLINDER ELECTRODE FOR ANODE POLARIZATION
MEASUREMENTS: J. Leistra, Carnegie-Mellon University, Dept. of Chemical Engineering, Schenley Park, Pittsburgh, Pennsylvania 15213; Dr. P. Sides, Carnegie-Mellon University, Department of Chemical Engineering, Schenley Park, Pittsburgh, Pennsylvania 15213
A rotating cylindrical electrode has been designed for use in cryolite melts. The apparatus includes a carbon crucible, a concentrically-placed BN cylindrical separator, and cyclindrical anodes connected to an inconel shaft 50 cm long that is rotated by a Pine-instruments precision rotator. The purpose of the rotation is to separate, insofar as possible, the "true" bubble-
Alkali metal impurities are always found in liquid aluminum metal removed from operating electrolytic reduction cells. These impurities have the potential to create problems in the further processing of the aluminum metal to fabricated products. A laboratory investigation of the effects of bath additives on impurity levels of alkali metals in aluminum was conducted. Bath additives investigated included: NaF, AlF , LiF, MgF 2' and CaF 2' 1 Definite correlations were found to exist oetween the amount of addit"ive in the bath and the impurity level in the metal. Laboratory results are compared with industrial cells.
(4:05 p.m.) AN ALTERNATIVE METHOD FOR EVALUATION OF RESISTANCE OF POT
INSULATION TO BATH ATTACK: Stig F. Johansson, Research & Development Center, Skarnol, Skarrehage Molervaerk A/S, DK-7900 Nykoebing Mors, Denmark The increasing use of heat insulating materials and the desire for improved energy efficiency in aluminum electrolysis pots has created a need for testing the products offered for pertinent properties. The resistance to penetrated bath being of decisive importance to the use in question, relevant methods for testing this property are searched for. The author describes a new cup method for testing bath attack on insulation, characterized by the simultaneous use of a eutectic sodiumaluminiumfluoridemelt and mixed-in molten aluminum. A quantitative measure of the degree of attack in each case is given, and basing on tests of 22 different siliceous materials it is concluded that generally the bath attack and the bulk density of the material are closely correIa ted.
120 TMS Annual Meeting
THURSDAY AM CHEMICALL Y INDUCED INTERFACE MIGRATION II Sponsored by the ASMIMSD Computer Simulation in Materials Science Committee and the TMS Chemistry and Physics of Metals Committee Thursday, March 6, 1986 Mardi Gras K 8:30 a.m. Marriott Hotel Session Chairman: J. K. Lee, Department of Metallurgical Engineering, Michigan Technical University, Houghton, MI 49931
(8:30 a.m.) EFFECT OF COHERENCY STRAIN ON INTERFACE MIGRATION: 1. OVERVIEW OF THEORIES AND EXPERIMENTS. Duk N. Yoon*, Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Seoul, Korea.
grow into the original Mo-Ni grains. Quantitative SEM/EDS measurements reveal that the recrystallized surface is enriched in Fe but has a much reduced Ni content. The observed concentration profiles indicate that this alloying/dealloying process is controlled by grain boundary diffusion. The obvious analogy to the phenomena of diffusion induced grain boundary migration is discussed with reference to the continuously varying diffusion geometry observed in DIR. This work was supPJrted in part by the Army Research Office.
(11 :05 a.m.) THE ROLE OF INTERFACE STRUCTURE IN CHEMICALLY INOUCED INTERFACE
MOTION: * J.C.M. Li, Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627.
The role of surface steps on the interfaces, ledges or steps on the grain boundaries and jogs and kinks on the dislocations is examined with respect to the transformation of the chemical driving force for diffusion to that for the interface or dislocation motion. Diffusibn of hydrogen along dislocations and grain boundaries to enhance dislocation motion and grain boundary emission is proposed as a mechanism for the effect of hydrogen on metal plasticity. The enhanced emission and motion of dislocations from crack tips by hydrogen diffusion is suggested as a possible reason for hydrogen embri ttlement. *Work started when the author visited B.B. Rath at the Naval Research Laboratory, Washington, D.C. and C.G. Park and S.M. Ohr a t the Oak Ridge National Labora tory, Oak Ridge, Tennessee.
When crystals are not in equilibrium with surrounding vapor, liquid, or solid, grain boundaries and liquid layers between them can migrate, leaving behind solid solutions closer to equilibrium. Temperature changes can also induce similar migrations. The migration sometimes results in precipitation of a new phase which in turn becomes a source of solute atoms. If the lattice diffusion ahead of the migrating interfaces is significant, coherency stress in the thin diffusion layer can contribute significantly to the driving force. Some critical experiments have been performed to show the effects of coherency strain on the migration velocity.
DEFORMATION III TMS-AIME General Abstract Session Mardi Gras E Thursday, March 6,1986 Marriott Hotel 8:30a.m.
*Part of thi s work was performed whi 1e the author was on sabbatical at the National Bureau of Standards in Gaithersburg, MD.
Session Chairman: Darcy A. Hughes, Div. 8316, Sandia National Laboratory, Livermore, CA 94550
(9:05 a.m.) EFFECT OF COHERENCY STRAIN ON INTERFACE MIGRATION: 2. BOUNDARY VALUE DIFFUSION PROBLEMS. John R. Manning, Metallurgy Division, National Bureau of Standards, Gaithersburg, MD 20899. When the interface migration velocity is sufficiently slow to give ri se to appreci ab 1e d iffus i on a head of the mi grat i ng interface, the theory of interface migration can be formulated as a boundary value problem for multi component diffusion in the self-stressed solids and either in the liquid film or along the grain boundary. The solutions to the problem for two and three component systems gi ve quant ita ti ve predi ct ions about ve 1ocity, interface shape and composition and stress profi 1es. Speci a 1 effects ari se in ternary systems that have no counterparts in binaries. In the range of temperature where these assumptions about diffusional penetration are valid, the theory is in good agreement with experiment. The work was supported in part by the Army Research Office.
(9:40 a.m.) EFFECT OF COHERENCY STRAIN ON INTERFACE MIGRATION: 3. QUANTITATIVE TESTS. Carol A. Handwerker, Institute for Materials Science and Engineering, National Bureau of Standards, Gaithersburg, MD. The coherency stress mechanism for interfacial migration continues to lead to new qualitative and quantitative predictions that are ng tested. Experimental observations from the literature will examined in light of these predictions, including a reexaminaof the experiments in the Au-Ag and the Cu-Ni systems. cal tests of the theory have been performed which demonstrate , in the cases examined, interface migration ceases when !coherency stress is eliminated. Quantitative experimental idence will be presented which addresses the issues of initiaon of migration, the effect of crystallographic orientation on gration velocity, and migration with insignificant lattice ·ffusion ahead of the moving interface (D/V approaches 0). supported in part by the Army Research Offi ce. Recu pera t i on
DIFFUSION INDUCED RECRYSTALLIZATION AT SOLID/LIQUID BOUNDARIES. hen Hackney, Instirtute for Materials Science, National - .. of Standards, Gaithersburg, MD 20899, Young-Joon Baik k N. Yoon, Department of Materials Science and Engineering, Advanced Institute of Science and Technology, Seoul, Korea. hen the liquid matrix of a liquid phase sintered Mo-Ni alloy is laced by Cu-Fe melt, small grains are observed to form and
(8:30 a.m.) HOT DUCTILITY BEHAVIOR Of HAYNES ALLOY 556: J J. Stephens. M. J. Ciesl~k, S~ndi~ N~tion~l L~bor~tories, Albuquerque, NM 87185* The behavior of Haynes Alloy 556 during a simulated arc weld thermal cycle has been investigated using Gleeble hot ductility tests. A nil-strength temperature of - 134D'C was determined for mill-annealed material. For specimens tested on heating, dynamic recrystallization, followed by grain growth, is observed. Dissolution of primary carbides (TaC) begins at 1200'C and a transition from transgranular ductile fracture to intergranular fracture occurs by 1280·C. Constitutional liquation of carbides is observed above 1280·C. On cooling from the nil-strength temperature, a return to ductile fracture is not observed until temper~tures below 1180·C. The metallogr~phic observations correlate with reduction in area measurements. The hot ductility behavior of this ~lloy is similar to that reported by other investigators for Inconel 718. *This work performed ~t S~ndia N~tion~1 L~bor~tories, supported by the U.S. Department of Energy, contract No. DE-AC04-75DP0078g.
(8:50 a.m.) TURBO 25 NICKEL BASE SUPERALLOY - Michelle K. Tripucka and John R. Mihalisin - Both at Howmet Turbine Components Corp. Alloy Division, Roy Street, Dover, New Jersey 07801
Turbo 25 is a nickel base superalloy that was developed specifically for investment cast automotive turbochargers where low alloy cost, good castability, and an attractive combination of physical and mechanical properties are critical criteria. Other growing and emerging applications for turbochargers such as trucks, buses, earth-moving equipment, farm tractors, and light aircraft will also benefit from the availability of this new alloy. The alloy is also being evaluated for use in aircraft and land base turbine rotors. Presented in this paper is updated information on physical characteristics of this alloy. These include high cycle fatigue data, thennal expansion data, and tensile properties when cast under commercial foundry conditions. In addition, the development of the alloy will be reviewed covering mechanical property data, structural characterization, and environmental resistance of the alloy.
TMS Annual Meeting 121 (9:10 a.m.) TENSILE DEFORMATION OF A POWDER PROCESSED Ni3A1 + Hf + B ALLOY*, P. Khadkikar and K. Vedula, Department of Metallurgy and Materials Science, Case Western Reserve University, Cleveland, OH 44106 and B. Shabel, Aluminum Company of America, Alcoa Center, PA 15069.
The
room
temperature
and
intermediate
temperature
tensile
behavior of a powder processed Ni3Al alloy with 0.1 at% B and 0.5 at% Hf will be discussed. Hot extrusion of prealloyed
powders results in a fine grained structure which exhibits good room temperature ductility. A Hall-Petch plot of yield strength as a function of grain size for this alloy shows that boron-containing alloys exhibit a shallower slope than undoped Ni3Al alloys. At elevated temperatures, however, the powder processed alloy remains brittle and the tensile fracture is intergranular. Tensile behavior of powder processed blends of NiAl and Ni3AI is being investigated and preliminary results will be presented.
*
(10:30 a.m.) THE INTERRELATIONSHIP OF PROCESSING, f1ICROSTRUCTURE AND MECHANICAL PROPERTIES FOR TUNGSTEN,NICKEL,IRON HEAVY ALLOYS:' D.V. Edmonds, Department of Mechanical Engineering, Naval 93943, J. B. Pos thi 11 , Pas tgraduate Sc hoo 1, Monterey, CA National Center for Electron Microscopy, Lawrence Berkeley Laboratory, University of California, Berkeley, CA 94720.
Research is supported by ALCOA.
(9:30 a.m.) EVALUATION OF THE LATTICE INCOMPATIBILITY MODEL FOR THE HIGH, TEMPERATUfE DEFORMATI2N OF ALPHA'~ETA TITANIUM ALLOY~:' ~ Damkro~er , B.B. Rath , M.A. Imam t and C.R. Edwards; (1) Center for We ding Research, Golden, Co. 80401; (2) Naval Research Laboratory, Washington, D.C.
The lattice incompatibility model for high~temperature deforma tion of alpha-beta titanium alloys has been evaluated. This model proposes that the elevated temperature ductility of these alloys is, related to the lattice contraction which occurs during the beta to alpha transformation. The lattice parameters of both phases of model alloys have been measured as functions of temp erature using x
(9:50 a.m.) THE PROPERTIES OF SEVERAL WELDED HIGH STRENGTH ALUMINUM ALLOYS by W. J. Lenllng, F. J. Worzala and K. T. Hartwig, Univ. of Wisconsin, 1509 University Ave., Madison, WI 53706. Two high strength aluminum alloys (Types 7075,T6 and 7005,T6) are being considered for use as structural support members for a large cryogen ic supe rconduct i ng energy storage magnet. Because welding is required, it is necessary to evalute the effect of the welding process on properties. The alloys were welded by three processes, conventional MIG, high current density MIG and electron beam. All wel ds were exami ned metall ographically. Hardness traverses were made to detennine the degree of softening at the wel d heat affected zone. Tensile tests were conducted at both ambient and 1 iquid nitrogen temperatures. The effect of post wel d heat treatment was al so investigated. Results of this evaluation indicate that the electron beam weld process produced superior wel d properties for both alloys. Some deterioration of properties was observed for the MIG processes, particularily at cryogenic temperatures. A post,weld heat treatment was found to parti ally restore properti es in the EB wel ded specimens.
(10: 10 a.m.) THE EFFECT OF SULPHUR ON THE HOT TENSILE DUCTILITY OF Cr-Mo-V STEEL, E.P. George and D.P. Pope, Dept. of Mat. Science and Engineering, Univ. of Pennsylvania, 3231 Walnut -Street, Philadelphia, PA 19104
Grain boundary sulphides are known to be potent cavity nucleation sites in low alloy steels which are tensile tested at elevated temperatures and slow strain rates. Ductility can be enhanced by preventing the precipitation of grain boundary sulphides by either alloying with a strong sulphide former like Mn, or austenitizing at temperatures below the dissolution temperature of the matrix sulphides. This study investigates the possibility of improving ductility by the alternative technique of keeping t~e sulphur content of the steel low. It is seen that "a Cr-Mo-V steel made with high purity electrolytic iron containing 1 ppm sulphur is ductile and does not cavitate at SOO·C, whereas a similar steel containing 30-50 ppm sulphur cavitates extensively, and fails intergranularly, when tested under similar conditions.
The various reactions that occur in tungsten,base heavy alloys during processing and heat treatment, that can affect significantly their mechanical properties, will be briefly summa ri zed. These inc 1 ude segrega t i on phenomena, hydrogen embrittlement and many different precipitation reactions. Mi croscopy and mi croana lyti ca 1 results will be presented for different W,Ni,Fe alloys with different processing histories. Possible alloy processing procedures will be suggested that 0l'timize microstructure and hence mechanical properties. This work is supported by the Procurement Executive, Ministry of Defence, R.A.R.D.E., U.K. and by the Director, Office of Energy Research, Office of Basic Energy Sciences, Materials Sciences Division of the U.S. Department of Energy under Contract No. DE,AC03,76SF00098.
(10:50 a.m.) ACCELERATED AGING OF METAL MATRIX COMPOSITES: I. Dutta and D.L. Bourell, Center for MS&E, Department of Mechanical Engi, neering, The University of Texas, Austin, TX 78712 A theoret i ca 1 numeri ca 1 mode 1 has been previ ous 1y deve loped I'(hich describes the anomalous accelerated aging of heat treatable metal matrix composite materials. The model was valid for a periodic array of spherical particles and of long, slender cylindrica~ particles loaded in plane strain. In the present work, the model for cylindrical particles is extended to incor, porate a thermally induced axial extension or compression. The effects of this axial strain on the resulting matrix plastic strain state and expended plastic strain energy are discussed. The role of axial thermal expansion on the accelerated aging phenomenon is also cons i dered. .
(11: 10 a.m.) THE PROPERTIES OF QUENCHED AND TEMPERED STEEL SHAPES WITH HIGH STRENGTH AND GOOD TOUGHNESS : KOZQ Fukuda J Nobuo Fukush ige, Fukuyama Labs. I Fukuyama-ci ty, H irash ima pr2.f. I Keij i Okamoto, Misao Makinohara, Fukuyama Works, Masahiro Ueda, Tokyo Head Office, NIPPON KOKAN K. K., Japan Quenching and tempering process, ....hich can heat-treat
homogeneously several kinds of large steel shapes, e.q. L 250ann x 250mm x 35mm, waS developed by reconstructing the conventional type continuous heat treating furnace specialized for annealing of steel shapes. Main considerations for reconstructing are, securing cooling starting temperature in quench by curtain burner, and unifying cooling rate at various positions by mist. Using this furnace, T.S. 60kgf/mm2 (ASTM A537'C1.2'Modify) and BOkgf/mm' (ASH! 514'B) grade steel shapes, and Q-T type 9% Ni (ASTM ASS3) steel shapes were tested and the
well satisfied results obtained, meeting the requirements of ASTM and having high homogeneity.
(11 :30 a.m.) MICROSTRUCTURE AND MECHANICAL PROPERTIES OF A 3Cr,l. SMa STEEL.' R. L. Klueh and A. S. Nasreldin, Oak Ridge National Laboratory, Oak Ridge, TN 37B31
Tensile and impact properties were determined for a 3 wt % Cr-l.5 wt % Mo-G.l wt % V-G.l wt % C steel in two heat-treated conditions: normalized and tempered and quenched and tempered. Similar tempering treatments (similar Hollomon-Jaffe parameters) for the quenched and the normalized steels resulted in similar strengths. However, the impact properties for the quenched steel at low tempering parameters (high tensile strength) were significantly better than those for the normalized steel with a similar strength. Only after the strength was further reduced by tempering did the impact properties for the normalized steel approach those of the quenched steel. The differences were attributed to differences in the microstructures: The carbide-free acicular baini te formed during quenching, and granular baini te formed during normalizing. *Research sponsored by the u. S. Department of Ent:!.rI5Y, AR&TD Fossil Energy Materials Program under Contract No. DE-AC05-840R214GO with the Martin Marietta Energy Systems, Inc.
122 TMS Annual Meeting
ENVIRONMENTAL CONTROL & HEALTH III Sponsored by the TMS Light Metals Committee Thursday, March 6,1986 Pontchartrain Ballroom B 8:30a.m. Sheraton Hotel Session Chairman; S. G. Epstein, Aluminum Association, Washington, DC 20006; and R. L. Byers, Aluminum Company of America, Pittsburgh, PA 15219
(8: 30 a ,m.) RECYCLE OF SPENT POTLINING THROUGH SODERBERG ANODES, E~R. Cutshall and L.O. Daley, Reduction Laboratory, Reynolds AlLUninum, p~O, Box 1200 Sheffield, AL 35660 A concept i& proposed for recycllng the carbon fraction of spent petliner (SPL) as a portion of the aggregate of Soderberg anodes. Prlor work in thl.S area has shown the feasibility of this concept for recycling small amounts of SPL carbon (1-3% of the total carbon aggregate). However, the present concept inv01 yes a Soderberg production facility which is operated primarily for the recycle of SFL carbon. The anodes of the cells would contain SPL carbon as 25-75% of the aggregate. Additlonally, any alumina insulatlon could be recycled as a portlon of the ore feed to these cells.
posal cost and burdening environmental regulatory compliance. The successful utilization of Spent Potliner ;]s a fuel addit Lve to cement kilns was previously demonstrated in the laboratory and in trial runs in op~rating cement kilns. This paper reviews the results of burning Spent Pot lining in a cement kiln on a long tenn basis over the last two years. Material handling and preparation methods are also discussed.
(10:30 a.m.)
A MEMBRANE PROCESS TO CONVERT SPENT POTLINING INTO VALUABLE PRODUCTS: G. Lever, Alcan International Limited, Kingston, Ontario, Canada K7L 4Z4. K. Mani, Allied Corporation, Aquatech Systems, 7 Powderhorn Drive, Mount Bethel, NJ 07060. J. P. McGeer, Alcan International Limited, P.O. Box 8400, Kingston, Ontario, Canada K7L 4Z4. Bench-scale results, and the resulting engineering and economic analysis of a commercial-scale plant for producing aluminum fluoride, caustic and an inert residue from used potlining, are described. An analy,.is of the heart of the process, an electrodialysis cell containing a water splitting membrane, is given. It is shown that the process is attractive from a financial, environmental and chemical engineering point of view. Process details touched upon include additional material values which can be recovered, the necessary purification steps required to maintain membrane life, product purities, process efficiencies and future plans.
The cyanide component of the potllner should be destroyed by the electrolysis process. Also, cryolite and valuable bath additlves such as Li and Mg should be recovered 1n the electrolyte af the operating cells. Electrolyte will be produced along with a de~reased grade of alumloum, due to the silicon and Han const1tuents of the SPL caroon. Product.s Wh1Ch are presently, or probably w1l1 be in the future, cansldered as hazardous are consumed by the proposed process.
(9:00 a.m.) THE DESTRUCTION OF SPENT POTLINING IN EXISTING KILN PROCESSES: J. Fi n 1ey Bush, A1umi num Company of Ameri ca, Alcoa Laboratori es, Alcoa Center, PA 15069 S1mulatlon studie .. of the deHruCt10n of spent potlining (SPlj a.. an add-on to three commerlcal \(11n proce .... es have been completed In lnter occurred In the 11r'1e-sorta slnter pror::es'!.. \ntrO<1uctlon of the '>PL through the flame Into the hot zone of the kiln was accomp1lshed wlth the e~pected results of hlqh F {'ml .... ,on In the
r
!~~c:ni~!~~! ~~ ~~: ~~r n~ySf~;se:~~s~l r~:a~ S~~! ~~~~~~~ ~~~~:~ ~~p ~~~ner
n 1 I re~u I ted 1 n ml ~ed ph"ses of ca 1c T[Jm a I uml nate,> from th!' al uml na I n the SPL. Thu'i. the calCIum lo<;.t lola,> '>lqnJFlc"ntly grf'ater than when" stOlchl0metrlc aroount of calClum was used ror rl'''etl0n WIth the fluorlnf". TtlI' small QUantlty of SPl burned Clurlnq the dol 11111' prOductlon (I part SPL!46 parts rlollme) resulted In d slqnlfleant lnerea..e In lmpurJty It;'vel~ In the DrQ(lur::t. This prevents the In(I\)$\on of the potl1nlng In the prncE'SS. ComOOSltlOn of Insolullle rf"~ldue In the 11",,.-.,oda SInter ororess W.H ChdMjPd due to tne formdtl0n of SOdIum dl-r::aIClum fluoro Sl11edte vs. the usual (jl-calr::\(,.Im s111cate. The Mldltl0n of tMe fluorlne lnr::red-sed the soaa IOHes slgnlflCantly atlovp prE'sent day values.
(9:30
a.m.)
FLUIDIZED BED COMBUSTION OF SPENT POTLINING, W.S _ Rickman, G.A. Technologies, W. F. Podolski, Argonne National Laboratory, and R.L. Byers, Aluminum Company of America
As
part
Technolo~ies
of
a
phased
program
for
the
.-\luminwn
.-\ssoclation,
GA
has sponsored and pedormed a senes of test bUr:1s to demonst:He
the combustion characteristics of spent jlotlinmgs. These tests demonstrated that: 1. Spent jlothniD~s can be burned reliably ·.vJ.thout generate a granular, free f:olOng ash.
3
s glomeratlon
to
A total of 21,000 pOlL"1ds
••
of ~pent. potlinings were burned during this 1)0 hours of test mg. Cvanlc1e destructIOn exceeds EPA's ha:.!:ardous waste InCineratIon
3.
crIterIa
even with
no sorbent
additIOn
to
(11:00 a.m.)
SOME HANDLING CONSIDERATIONS FOR SPENT POTLlNIN:>. O. R. Augood, Kai ser A1 umi num & Chemi ca 1 Corporati on, Pleasanton, CA. 94566. Setting cyanide apart, the properties of spent potl ining (pL) as they affect handl ing, shipping and/or processing are discussed. The nature, amount and rate of formation of gas evolved when PL reacts with water are determined. Variables include the source of PL, particle size, water to PL ratio, and temperature. The major components of the evolved gas are methane, hydrogen and ammonia -- which are flammable and, under certain conditions, explosive in admixture with air. Small amounts of other saturated and unsaturated hydrocarbons (with only a trace of acetyl ene) are al so formed. Most of these gases are non-toxic and ammonia has a relatively high tolerance level. Given reasonable assumptions, the atmosphere that arises in a hopper car when a small amount of water reacts with the PL contained therein appears to be nonexplosive. Clearly, however, it is important to keep PL dry and/or ventilate any storage/transportation vessels. While weathered PL exhibits decreased gas potential, calcined PL surprisingly shows some acti vity. r~Dderately-sized and aged PL is relatively non-combustible.
EXPERIMENTAL METHODS FOR MICROGRAVITY MATERIALS SCIENCE RESEARCH VI Sponsored by the Thermodynamic Data Committee, Materials Science Division, American Society for Metals Thursday, March 6,1986 Mardi Gras C 8:30 a.m. Marriott Hotel Chairman: R. A. Schiffman, Midwest Research Institute, Kansas City, Missouri 64110 Session Chair: R. J. Bayuzick, Department of Mechanical and Materials Engineering, Vanderbilt University, Nashville, Tennessee 37235
the combustor.
These emiSSIOns averaged less than 3 pounds of fluoride per ton of spent potlinmg treated. 4.
Spent
potlinmgs
r~qulre:nents
can
temporarv t!'im during 5.
'::le
burned
'N1t!l
low
aUXiliary
fuel
such t:'at auxiliary fuel mav only be reqUired as a lon~
(8:30 a.m.)
t'!Mll op'!ratons.
Approximately 10% of t~e carbon in the fr'!sh pot;;nln~s left the umt as unburned fine carbon.
It should be pOSSible to further
combust this small reSidual stream of carbon by
r~cyclt;'l'5
the
el.utriated fines back to the CIrculating bed. 6.
Volume reduction ratIOs are greater than Z:l.
POTLINING AS AN ADDITIVE TO CEMENT KILNS:
of South Carolina, P.O. Box 1000, Goose and recycling of Spent Potlining in cornmerboth necessary and needed to avoid high dis-
ADVANCES IN LEVITATION TECHNOLOGIES FOR SPACE PROCESSING: P. Behrmann, ESTEC, Noordwijk, The Netherlands, H.G. Lierke and R. Gross6ach, Battelle, Frankfurt, W-Germany Two levitation techniques -acoustic and electrostatic levitationare being developed as part of the European Space Agency's Technology Research Programme. Both levitators are expected to be used primarily in materials science applications. The acoustic levitator features a detuned tube levitator operating in the 1,0 Bessel mode. The electrostatic levitator uses the well-established tetrahedral electrode array. 80th levitators operate in conjunction with a multi-axis optical position sensing system. The paper will summarize rocket flight test results on the acoustic levitator, describe concepts for improved position sensing and control, present breadboard results to back up these concepts, and give an outline of the future flight demonstration programme assoc i ated with th i s development.
TMS Annual Meeting 123
(9:00 a.m.)
ON MICROGRAVITY SIMULATION BY NEUTRAL BUOYANCY TECHNIQUE, J. Meseguer and A. Sanz, Laboratorio de AerodinAmica, E.T.S.I. Aeronauticos, Universidad Polit~cnica, 28040 Madrid, Spain. The study of liquids in microgravity conditions appears as B
very promising field owing to the large number of applications in space technology. The expenses and difficulty involved in performing space experiments is one of the reasons to develop experimental support on Earth. The use of neutral buoyancy technique offers to scientists a cheap, short time preparation medium for experimentation with interfaces in simulated microgravi ty. Concerning axisymmetric interfaces, this technique has been used for a long time for static processes and recently some successful attempts have been made in connection with the dynamics of liquid bridges. In this paper the main effects on the dynamics of a liquid bridge due to the presence of an outer liquid, as occurs in experiments using the Plateau-tank technique, are considered. In addition, the influence of experimental boundary conditions is discussed.
(9:25 a.m.)
MEASUREMENT OF PHYSICAL PROPERTIES OF MATERIALS USING ACOUSTIC
LEVITATION*: E.H.Trinh, Jet Propulsion Laboratory, Pasadena, ·CA. Microgravity conditions allow the processing of materials in a containerless manner through acoustic (or other) positioning and manipulation techniques. The interaction of the acoustic radiation pressure with the liquid and solid samples also allows the measurement of certain properties of the materials under scrutiny. The density, surface tension, viscosity, index of refraction, and compressibility can be measured using samples with size ranging from 1 em down to 500 micrometers. An important application lies in the determination of the properties of substantially undercooled liquids.
electrodynamically in vacuum in a quadrupole trap. Wa.ter vapor is slowly introduced causing theparticle to undergo sequential crystalline phase changes to the hydrated solids LiI'nH 0 with n = 1, 2 5/3, 2, 3. The pressure at each change is measured. The vapor is slowly removed and changes to n = 2, I, 0 occur at which the pressure is measured. Hysteresis occurs. The results are analyzed using simple nucleation theory to determine the free energy barrier to the transitions. The transition from Lil·3H 0 to saturated solution is also studied. The results suggest ~he existence of an intermedia.te solid state consisting of water molecules absorbed between the graphite-like crystalline layers. *Work supported by NSF. **Present address: Argonne Na tional Laboratory. (11:25 a.m.)
THE MICROGRAVITY MATERIALS SCIENCE LABORATORY - AN OPPORTUNITY: L. A. Greenbauer-Seng, NASA Lewis Research Center, Cleveland, OH. The Microgravity Materials Science Laboratory (MMSL) is a nationally available facility located at the NASA Lewis Research Center. The MMSL is open to scientists from industry, univers ity, and government Organ i zat ions to study and develop thei r microgravity materials science experimental ideas. Visiting scientists may conduct experiments as precursors to the use of ground-based reduced gravity facil ities or in preparation to qualify a materials science experiment for a Space Shuttle f1 i ght. The MMSL conta ins funct i ona 1 dup 1 i cates of Shutt 1e flight hardware for research at one-g; the first step toward understanding the affects on materials and processing phenomena at low gravity. Initially metal and alloy solidification and crysta 1 growth resea rch wi 11 be supported, however, equ i pment required for microgravity-re1ated research on glasses, ceramics, and polymers wi 11 soon be added. Extens i ve materi a 1s cha racterization laboratories and advanced computational capabil ities are also available to support the research. A description of the experimental capabil ities provided in the MMSL and the process for app1 ication will be presented.
Work supported by NASA (11 :50 a.m.) ELECTROMAGNETIC CONTAINERLESS PROCESSING: (9:50 a.m.)
THE EFFECTS OF GRAVITY LEVEL DURING DIRECTIONAL SOLIDIFICATION ON THE MICROSTRUCTURE OF Al-In-Sn ALLOYS: **p .A. Curreri,
*VI.F. Kaukler, and **M.H. Johnston, **NASA/MSFC, *The UniverSity of Alabama in Huntsville, Department of Chemical Engineering Al-18In-xSn, (x = 0,6,14,22), slightly hypermonotectic alloys were directionally solidified during aircraft low-gravity (low-g) maneuvers each consisting of about 25 seconds of low-g (I 0-2g) and 1 minute of high-g (I. 5g) •
Typical1y, several
millimeters of sample was solidified in each low-g period. Calculations and work with transparent metal model materials indicate that convective and Stokes flows are damped by a factor of 100 within 4 seconds in low-g. Sample composition and microstructure were correlated with accelerometer data. For the 6 and 14 wt.% Sn alloys envelopment of L2 phase by the solidification front and for the 22 wt. % Sn alloy the allignment and shape of the In-Sn rich phase appeared to be a function of the gravity level during solidification.
(10:15 a.m.)
BREAK
(10:35 a.m.)
A COMPARISON OF DIRECTIONAL SOLIDIFICATION IN A MAGNETIC FIELD AND UNDER MICROGRAVITY CONDITIONS AS A MEANS OF CONTROLLING NICKEL BASE SUPERALLOY MICROSTRUCTURES: W.S. Alter*, J.B.
Andrewst, M.H. Johnston*, P.A. Curreri*, w.n. Hamilton*, *NASA Marshall Space Flight Center, Huntsville, AL 35812,
EML Shuttle Apparatus and
Experiments Robert T. ,Frost, General Electric Co. Space Division, Valley Forge, King of Prussia, PA. The apparatus, recently rebuilt and Qualified for melting and solidification experiments in the orbiter cargo bay is described, as well as the status of the initial series of planned experiments using the facility and plcn'lE'd modifications. The present device utilizes high power RF induction melting, followed by nearly zero power electromagnetic positioning. A specimen exchanger, pyrometer and movie camera are provided for observation of sequential specimens during meltinq or during ~ub~~Quent undercooling and recalescence. Capabilities will be described as well as a brief summary of the on-going experiments. (subject to formal GE management approval)
EXPERIMENTAL TECHNIQUES IN HIGH TEMPERATURE SCIENCE VI Sponsored by the Thermodynamic Data Committee, Materials Science Division, American Society for Metals Thursday, March 6,1986 Mardi Gras F-G 8:30 a.m. Marriott Hotel Chairman: R. A. Schiffman, Midwest Research Institute, Kansas City, Missouri 641 IO Session Chair: D. R. Olander, Department of Nuclear Engineering, University of California at Berkeley, Berkeley,CA 94720
tUniversity of Alabama at Birmingham, Birmingham, AL 35294
Variations in carbide morphology and volume fraction are often found in directionally solidified superalloys and are thought to have a significant influence on the service life of components. Recent research has indicated that directional solidification under microgravity conditions can affect the shape and volume fraction of the carbide phase in these alloys, presumably due to the reduction of gravity induced flows such as convection. In this study, a magnetic field was utilized to dampen fluid flow during ground based directional solidification experiments. A comparison has been made between the carbide morphologies and volume fractions in MAR-H 246 superalloys directionally solidified under a magnetic field and under microgravity conditions. ili'Work has been supported through the Marshall Space Flight Center Materials and Processes Laboratory
(11:00 a.m.)
MEASUREMENT OF PHASE CHANGES IN A LEVITATED LITHIUM IODIDE
PARTICLE*. C. B. Richardson and C. A. Kurtz**, Physics Department, UniverSity of Arkansas, Fayetteville, AR 72701 A charged micron-size particle of lithium iodide is suspended
(8:30 a.m.) DYNAMIC TECHNIQUES FOR MEASUREMENTS OF THERMOPHYSICAL PROPERTIES
AT HIGH TEMPERATURES: A. Cezairliyan, National Bureau of Standards, Gaithersburg, MD. Techniques are described for the dynamic measurements of selected thermophysical properties of electrically conducting solids in the range 1500 K to the melting temperature of the specimen. The techniques are based on rapid resistive self-heating of the specimen from room temperature to any desired high temperature in less than one second by the passage of an electrical current pulse through it and on measuring the pertinent quantities with millisecond resolution. The techniques were applied to the measurements of heat capacity, electrical resistivity, hemispherical total emissivity, normal spectral emissivity, thermal expansion, temperature and energy of solid-solid phase transformations, melting temperature, and heat of fusion. Extension of the techniques to measurements above the melting temperature of the specimen are briefly discussed.
124 TMS Annual Meeting (11:00 a.m.)
(9:00 a.m.)
THE EFFECT OF INTERFERING RADIATION ON PYROMETER SYSTEMS FOR MEASURING TURBINE BL~DE TEMPERATURE
Mark Wrigley, Negretti Aviation, Southampton, England Measurement of gas turbine blade and disc temperature by infrared thermometry is now a well established technique. Principally the method employed has been to calculate temperature
from the amount of radiation emitted by a target over a specific wavelength interval. This single colour SYRtPffi is subjPct to errors caused by various conditions which exist in the turbine
engines. Lens obstruction, bladed emissivity, hot carbon particles, flame and reflected radiation can all seriously effect the output of the transducer. Two colour pyrometry transducers detect radiation over two different wavelength intervals. Suitable processing of the outputs can detect and/or overcome the above errors. This paper uses computer modeling to predict the effects of such interfering radiation on both single and two colour pyrom2ter systems. The models are used to identify the optimum two colour system and evaluate how effectively interfering radiation can be detected.
VARIABLE CAPJ\CIT1IN:E VlBRATICN TRlINSIXX:ER FOR USE AT HIGH TEMPEIlA'lURE AND HIGH PRESSURE*, G. A. Rinard anl. D. E. Rugg, Dernrer Research Institute, Dernrer, Colorado A variable Capacitance Vibration Transducer (CIIT), capable of operatin} at very high tarperatures anl. pressures, is descrihErl. '!he ootput of the CIIT is directly prcportional to velocity. Signal concli. tioning provides addi tional oulplts prcportional to acceleration anl. displacerent. '!he CVT was develq>ed to measure the rapping characteristics of the collection plates of an electrostatic precipitator for use on the fuel gas stream fran a flui~zed_beQ ooal gasifier. Vibration measurerents were made at 870 C (1600"F) anl. 2 ~ (20 atrn). A discussion of the principles of operation of the CIIT is given together with an analysis of the sensitivity anl. linearity. A carparison of the output of the CIIT with that of a conventional piezoelectric acceleraneter is given. Test results of precipitator plate rawing are discussed.
* 'Ihis
work was stq::pOrted by the U. S. Department of Energy, Morgantam Energy Technology Center.
(9:25 a.m.)
(11:25 a.m.)
SURFACE TEMPERATURE MEASUREMENTS OF A SODIUM COOLED SOLAR CENTRAL RECEIVER USING AN INFRARED IMAGING SYSTEM G.Lemperle and W.Schiel DFVLR EN-TT, West Germany The receiver of a Solar Tower System is the component where concentrated solar radiation is converted to thermal energy. Since up to 1.5 MW/sq m radiant flux density is reached on the surface of the metal tubes any attached thermocouple or its wiring would be destroyed or at least disturb the temperature distribution. So an
EXPERIMENTAL TECHNIQUE FOR THERMODYNAMIC ANALYSIS OF FERRITIC ALLOYS: H. Wada, Department of Materials and Metallurgical
infrared imaging system was used to measure the temper-
ature distribution of the Advanced Sodium Receiver of the SSPS project at Almeria, Spain. To minimize errors
by reflected solar radiation the detector operates in the favorable atmospheric window at 8-12 ~m. The estimate of the total error yields i10 0 C mainly caused by the variation of the surface emissivity. There is a good agreement between measurements and calculation.
Surface temperatures up to 700°C were measured.
Engineering, University of Michigan, Ann Arbor, Michigan 48109 Mul tidiciplinary experimental procedure were applied to thermodynamic analysis of ex-carbides equilibrium in ex-Fe-Cr-Mo alloys. Specimens were equilibrated at 98SK by a gas flowing method with fixed ratio CH4/H2 gas mixture and a capsule method wi th reference alloys. Total carbon content, carbide species and partitionings of alloying elements in the two phases were analyzed. Total carbon content in high Cr alloys was lower in the capsule method due to Si contamination. Application of atomic absorption spectrometry to a-matrix solution separated from carbides was most reliable when considerable amounts of carbides were present. Carbide phase analyses by SEM-EDX and by EPMA showed a good agree-
ment, if standard samples were properly provided. A solution model applicable to a-carbides equilibrium was developed from experimental resul ts for ferri tic Fe-Cr-Mo-C allays. The research was supported by the Energy Research Office of the Uni versi ty of Michigan.
(9:50 a.m.)
DESIGN OF EXPERIMENTS FOR THE ELECTRODYNAMIC THERMOGRAVIMETRIC ANALYZER: P. Bolsaitis, R. E. Spjut and J. F. Elliott, Dept. of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139 The Electrodynamic Themogravimetric Analyzer is a recently developed device which permits very rapid heating of a small particle (approx. 5 to 100 microns) to very high temperatures (>5000K). The wavelength of the heat source (C02 laser - 10.6 microns) and the typical particle size combine to place the system in the Mie absorption regime where the optical properties (index of refraction, extinction coefficient) of the material become critical in defining the heat transfer rates. The heat transfer rates are, in turn, critical in defining the reactions whose rates may be quantitatively determined in the EDTGA. Experimental results on the transient temperature behavior and equilibrium temperatures obtai ned with 1 i mestone, a 1 umi na, and tungsten parti c 1es heated in the EDTGA are analyzed in terms of simplified heat transfer representations (lumped and distributed parameter models) and the heating and temperature sensing devices used in the experimental set-up.
(10:15 a.m.)
(11:50 a.m.)
CONTINUOUS X-RAY DIFFRACTION OF PHASE TRANSFORMATIONS AT HIGH TEMPERATURES: * R.R. Reeber and E. Smel ik, University of North Carolina at Chapel Hill, N.C. A new technique for controll ed heating and cool ing of material s while simultaneously and continuously recording their Laue diffraction patterns is described. The reversibility and irreversibility of several transitions in tridymite (a polymorph of quartz) are illustrated by the computer-controlled method. The present system can be operated over the temperature range 100- 1000 K. Heating and cool ing rates from .1 to 5 degrees/ exposure are readily attainable for exposure times of 15 minutes. The program for system control of the Commodore Vic-20 computer will be described and impl ications and prel iminary results for interpretation of elastic constant variations in the vicinity of phase transformations will be given.
*
Thi s work was supported by the Army Research Offi ce
Break
MASS SPECTROMETRY TO STUDY GASEOUS METAL CLUSTERS
M. S. Chandrasekharaiah, J. E. Kingcade, R. tter, Karl A. Gingerich, Chemistry Department, Texas A&M ity, College Station, TX 77843. metal clusters and carbide species have been extensively during the past few years both from the view points of bonding and technological applications. Our research made valuable contributions to the understanding of and bonding of these species. High temperature mass spectrometry has proved to be an invaluable lexperimental method in elucidating the thermodynamic stability of ese transient species. In this presentation, the uniqueness of is experimental method in the study of metal clusters will be scussed along with our newer results.
GENERAL PYROMETALLURGY II Sponsored by the TMS pyrometallurgy Committee Thursday, March 6, 1986 La Galerie 1 8:30a.m. Marriott Hotel Session Chairmen: Graham Eacott, Graham Eacott & Assoc., Suite 301,55 University Avenue, Toronto, Canada N5J 2H7; and Goran Lindkvist, Manager Metallurgy Department, Boliden Metal AB S9300 Skelleftehamm, Sweden
(8:30 a.m.) START -UP OF METALLURGICAL PLANTS
I
was supported by the National Science Foundation
John C. Taylor. P. Eng. Metallurgical Consulting Engineer Jan H. Reimers and Ass. Inc •• 221 Lakeshore Road East, Oakville, Ontari o. Canada As part of the organization of a metallurgical project. whether it be greenfield or a modification. planning for the start-up should begin with the organization of the project.
TMS Annual Meeting 125
The key to a successful start-up is a clear definition of responsibility and planning for the start-up early in the engineering phase. Planning should include the scheduling .of construction so that individual areas can be run-in and the necessary modifications carried out well in advance of the start-up of the total complex.
forces. there is a need for more cost effective process plants with proportionally greater interest in smaller scale operations. Many of these contract opportunities require a more flexible approach to real ization. They are often overseas and in remote locations yet require "state-of-the-art" technology which demands a novel approach to project design and execution.
Based on the author's experi ence wi th start-up opera ti ons, an organizational approach is outlined. Points which are frequently overlooked in the rush to bring a metallurgical plant on-line are summarized, and a procedure suggested to minimize problems during early operation.
Tolltreck is particularly active in supplying medium scale process plants and the paper describes project contracting and mechanisms that the company has used with success.
(8;55 a.m.) THE ECONOMIC AND ENGINEERING ISSUES FOR SUCCESSFUL START-UP: L. R. Verney, Union Miniere, Belgium. SUCCESSFUL START-UP OF MAJOR GREEN-FIELD OR RETROFIT PROJECTS.
OF
I"'CREASING COMPLEXITY. REQUIRES CONSIDERABLE PRELIMINARY COMMITMENT BY INTENOING OPERATING COMPANIES TO DETAILED TECHNOLOGIC;'L. ENGINEERING AN(I FINANCIAL EVALUATION ANO TO THE PROVISION OF EXPERIENCED OP6RATlNG PERSONNEL (lURING EI,IALUATION. DESIGN AI\I[, START-uP. COMPANIeS ASSOCIAIE(I wl1H SUCCE5SFUL START-UP ALMOST
INVARIABLY COMMIT FRONT-ENe, FUNOS AND MLJCH TIME TO ANALYSIS OF ALL ASI"'f.:CTS RESC:A~Crt ANU (,~ ... i:LO;>M£N r. Pl1..01 PLANr waR". SUFF 1elENT PRELIMINARY ENGlt~EERlfl.lG TO ENSuRE PRE?ARAT ION OF ,AOEQUATE GENERAL ARRANGEMENTS SO AS TO it..::: A~l.t:: TO ':::STIMATt:: STRUCTURAL QUANTITle:S AND TO e'ETERMINE SUFFICIENT S"'ECI"'ICATlON~ FaA COST EVALUATION OF AT LtA5T bQ PC OF THe: MAJU" £.;lULPM£N I, AN(I £)(HAl.ST IVE:' FINANC.IAL. ANALYSIS - SEf'ORE MAKING AN IFfFfEVO':'Ae.L.E. C.OMMIIMEN.T.
F"EOuENTL.Y SUCH COMPANIES HAVt:: .BOTH INTEGRATE(l R AND (I AN(I CON:iIOEFcAe.I...E IN-HUUSE ENGINEERING CAPA~HLI TY. HOWEVER, IN SOME CAS'::S. THIS WOR,.. MAY e.€: PROVl('ED BY ENGINF"ERING COMPANIES WHICH MAINTAIN HIGH CALIe-AE TECHNOLOGICAL GROUPS AND WHICH ALSO MAINTAIN THEIR OWN RAND D AND PILOT PLANT FACILITIES SO AS TO fiE A9.LE TO ['EVr.LOP THI: PRELIMINAHY WOR'" IN COOPERATION WITH CLIENT OPERATING COMPANIES. NECESSARILY. IN SUCH CASES. CLIENT COMPANIES MUST I'IAHHAIN CLOSE CONTACT WITH THE ENGINEER1NG COMPANY, EITHER 6'1' HAVING THEIR OWN RE?RESE,HATIVES PRESENT IN THE ENGINEERING COMPANY OFFICES OA ey HAVING THE ENGINEERING COMPANY PROVIDE A uROUP IN OR NEAR THE CLIENT COMPANY OPERATIONS. UNFORTUNATEl..'( MANY OF THESE ASPECTS ARE FRt:::OU£NTLY IGNORED, TO THE POINT THAT SOMETIMF.5 THE FIN,:,r~CIAL SOLVENCY OF OPERATING COMPANIES IS JEO?AtH'ISE[' ':'ND THE CREC>IeiLITY OF ENGINEERING COMPANIES 15 PUT AT RISK.
\Y:~U a.m.) PROJECT ENGINEERING AND PLANNING OF MAJOR SMELTING PROJECTS: D. Edward Holt, ASARCO, Inc., Salt Lake City, Utah
It has been said, "Without a plan for getting where you want to go, any road you take will get you there". Planning, prior to canmencement of engl.neering design, is essentl.al to surt any project in the right direction. Constant plannl.ng throughout the ll.fe of the proJect, whether engineerl.ng or construction or both, is essential for the successful completion of the proJect. Every project exists within the framework of three l.nterrelclted constraints; time, money and people. Sal.d another W.ly these are schedule, budget and organl.zation. These constraints .1150 happen to be the resources or assets by which the work is accor.'lplished. Proper development and use of the resources will do r.'Iuch to ensure that the proJect is completed wlth.ln the limits of the constr31nts. proJect eng.lneering or m.ln
(9:45 a.m.) EFFECT OF HAZARDOUS WASTE MANAGEMENT REQUIREMENTS ON THE OPERATION OF PYROMETALLURGICAL PLANTS: E.S. Geskin and D.J. Watts, Department of Mechanical Engineering and Institute for Hazardous and Toxic Waste Management, New Jersey Institute of Technology, Newark, New Jersey 07102 A comprehensive approach to the handling of wastes from ore smelting, metal refining, and processing is discussed. The EPA has identified 36 streams of hazardous substances generated during metal production, 9 in ferrous metal production. The Congressional Budget Office estimates the primary metals industry was the second larges.t contributor to the 1983 U. S. hazardous waste production. New environmental rules encourage modernization of metallurgical plants and modification of metallurgical technology. The effectiveness of recycling for waste management is demonstrated by the utilization of sludges from steelmaking furnaces and previously landfilled steelmaking slags. The feasibility of a waste-free metallurgical plant is discussed.
(9:30 a.m.) ELECTRON MICROSCOPY OF GRAPHITE/ALUMINUM: M. Vedula, Graduate Student and R. A. Queeney, Professor, Department of Engineering Science and Mechanics, The Pennsylvania State Uni versi ty, University Park, FA 16802.
Graphite/alumim.un is examined by transmission and scanning electron microscopy. TEM diffraction patterns are analyzed and the compolUlds present in this composite are AI~B48C2' AI~Mo3C' Mo 12 Cu Al lC and AgAI02. Energy dispersive an!llysis in "he SEM 6 shows ~hat SlIVer is present only in the matrix and molybdenum occurs only at the interface. This implies that the carbides, ~12M0"3C ~nd M012C~lAI1I Ch , are present at t~e interfac:, and lnterf"aclal reactH:5n must have occurred durlng process~ng.
(10:00 a.m.)
BREAK
(10:30 a.m.) (10:10 a.m.) EFfECTIVE LOW COST PROJECTS J. G. Whellock Tolltreck In.ternationa1, Denver, Co1. The demand for 1arge turn-key contracts has dimi shed over recent years in line with falling metal prices and world recessionary
CARBIDE FORMATION AT ALUMINUM-GRAPHITE INTERFACES: B. Maruyama and L. Rabenberg, Department of Mechanical Engineering, Center for Materials Science and Engineering, The University of Texas, Austin, TX 78712 The formation of aluminum carbide at the interface between a 1umi num and graphite has been cha racteri zed by ana 1yt i ca 1
126 TMS Annual Meeting electron microscopy and Auger electron microscopy in an effort to understand and control the properties of aluminum-graphite metal-matrix composites. Carbide formation in these composites is known to be detrimental to their mechanical properties because it degrades the fibers and develops sites of enhanced stress concentrations. Crystalline graphite powders and controlled impurities were introduced into Al and consol idated into geometries suitable for cross-sectional thin foil preparation and surface Auger analysis. The carbide formation reaction occurs preferentially at specific types of positions and crystal orientation of the graphite and is catalyzed by the presence of aluminum oxide. The roles of oxygen and other intentionallyintroduced contami na tes wi 11 be di scussed.
(11: 00 a.m.) COMPOSITE AND FIBER STRENGTH DEGRADATION AS A RESULT OF PROCESSING AND ALLOYING IN PRESSURE INFILTRATED CARBON FIBER REINFORCED ALUMINUM ALLOY MATRIX COMPOSITES: J.A. Cornie, R.G. Dixon,
M. Meaney and M.N. Gungor, Materials Processing Center, M.l.T. Cambridge, MA
02139
Preforms of P-55 Carbon fiber were pressure infiltrated with unalloyed AI, AI-2%Mg, AI-4.5%Cu, Al-7%Si, and Al-2%Li (A-357) and
evaluated for axial and transverse tensile strength. Fibers were leached from the composites and tensile tested to determine the degradation as a result of the pressure infiltration environmental exposure. Fibers leached the Ai-S1 alloy were least degraded by the processing sequence followed by Ai-Cu, Al-Mg and AI-Li
being the most severely degraded.
The composite axial tensile
strength agreed very well with the leached filament results. However, the composite transverse strength was highest with the AI-Mg matrix followed by AI-Cu and AI-5i being the lowe,st. A metallographic analysis of the cast matrix structure is similar to earlier results with Al203 and SiC fibers from this laboratory. An Auger analysis was determined on the fracture surfaces. The presence and morphology of Aluminum Carbide at the fiber/matrix interface is related to the transverse tensile strengths measured.
PHASE DIAGRAMS FOR ELECTRONIC MATERIALSPROGRESS & OPPORTUNITIES II Sponsored by ASM·MSD Alloy Phase Diagram Activity Thursday, March 6, 1986 Mardi Gras H 8:30 a.m. Marriott Hotel Session Chairman: Dr. Robert A. Laudise, Director, Physical & Inorganic Chemistry Research Laboratory, AT&T Bell Laboratories, Murray Hill, NJ 07974
(8:30 a.m.) THERMODYNAMIC CONSIDERATIONS IN THE SYNTHESIS AND CRYSTAL GROWTH OF GaSb: K. B. McAfee, Jr., D. M. Gay, R. W. Hozack, R. A. Laudise, G. S·chwartz, rA. Sunder, Physical and Inorganic Chemistry Research Laboratory, AT&T Bell Laboratories, Murray Hill, NJ 07974 We aoply a new and powerful thermodynamic tool to examine the growth of GaSb from a thermodynamic viewpoint. The technique we have developed minimizes the Gibbs energy of the multi-phase growth system comprising a gaseous phase and several condensed phases. Ga203 is identified as the most stable contaminant compound. It 1S also seen in the form of a bright lace-like low density phase which covers the melt. The physical effect of the material is very often to prevent the growth of hiqh qual ity crystals and it may also be important in determining their electrical properties. This paper shows the effects of increasing the ambient hydrogen concentration upon the oxide thickness. It also determines that the Si0 crucible is not an important 2 source of the contaminant oxygen except at very high temperatures. The Gibbs energy minimization method combined with the newlydeveloped optimization algorithm is an efficient tool for use by the materials scientist in evaluating the problems of crystal growth.
(9: 00 a:m.) CALPHAD GENERATED MULTI COMPONENT PHASE DIAGRAMS FOR ELEMENTS II THROUGH VI: Larry Kaufman, ManLabs, Inc., Cambridqe, MA 02139 Alloy semiconductors are important for electrooptical applications because they can be tailored by controlling the composition of the solid, which is grown from the liquid or deposited from the vapor. Although crystal growers are adept at controlling the temperature (and pressure) of the parent phase to obtain desired ~haracteristics of crystalline alloy semiconductors, phase diagram data is indispensable to deal with increasingly complex systems. The CALPHAD method for coupling phase diagrams and thermochemical data is being applied to construct a data base for the twenty five elements in Group II through Group VI.
This data base permits computation of solid/liquid and vapor/condensed phase equilibria over wide ranges of temperature, pressure, and composition. Examples illustrating this data base will be presented covering III-V binary and ternary systems, Hg-Cd-Te, AI, Ga and In-N, Ge-Se and As-S, Al-Bi-Ga and AI-Ga-As-Ge. (9:40 a.m.) The Importance of Morphotropic Phase Boundaries in Ferroelectric Solid Solution Systems, L. E. Cross, Evan Pugh Professor of Electrical Engineering. Pennsylvania State University, University Park, PA
16802
In the PbTi0 -PbZr0 (PZT) solid solution system, the near verti3 3 cal ferroelectirc-ferroelectric phase boundary (Morphotropic Phase BrJUndary, MPB) near the 50-50 Zr-Ti composition is widely used to enhance the piezoelectric response in poled ceramics at compositions near the boundary. In a recent development of the LandauGinzburg-Devonshire phenomenology for the PZT solid solution system, we are able to derive values for the intrinsic response in dielectric and piezoelectric tensors and see the significant enhancement of t:11 and d ,) in the tetragonal phase compositions 1 close to morphotropy; For Pb _ Ba Nb 0 solid solutions, the 1 2 6 morphotropic phase boundary occGrsxnear the 60-40Pb-Ba composition. Using a similar phenomenological model, we again predict for tetragonal ferroelectric compositions close to the MPB very high values of permittivity, Ell' the piezoelectric tensor, d ,) and l the electro-optic tensor, r ' For these compositions, unlike Sl PZT's single crystals can be grown and the predicted single domain values check well with experimental measurements.
(10:20 a.m.) PHASE EQUILIBRIUM PARAMETERS FOR TilE Hg
Cd Te ALLOY SYSTEM:
*Ernestine K. Cothran, F.R. Szafran, and-~.L~ Lehoczky, Space Science Laboratory, NASA Marshall Space Flight Center, Huntsville, AL Since the publication of the comprehensive measurement of the pseudobinary HgCdTe phase diagram by two of the authors, additional data for the ternary diagram have been published by us and others which makes it possible to refine some of the corrections made for our original pseudobinary data. We have also developed the capability to numerically fit the differential thermal analysis (DTA) curves from which the phase diagram was derived. This fitting procedure uses physically meaningful parameters such as liquidus and solidus temperatures, heats of fUSion, etc. which permits additional refinement of the phase equilibruim parameters. We will present the slightly revised phase diagram but primarily we will discuss the fitting procedure for the OTA curves which is applicable to a wide range of systems in addition to HgCdTe. *Work supported by NASA Microgravity Science and Applications Division.
(10:50 a.m.) THERMODYNAMIC PROPERTIES AND PHASE EQUILIBRIA OF Pb-Sn-Te AND Pb-Sn-Se: J-C. Lin, T-W. Ngai, A. Schultz, and Y. A. Chang, University of Wisconsin-Madison, 1509 University Ave., Mad1son, WI 53706. In this presentation, we will cover (il thennodynamic measurements of tellurides by emf; (iil phase equilibrium detennination with OTA, microprobe, metallographic and x-ray studies; (iiil defect structures of the telluride phases; (iv) phase diagram calculation/prediction of the binary and ternary systems; and (v) computer-graphics to represent the phase equil ibria of the two ternaries. (11: 20 a.m.) GENERAL DISCUSSION
PHASE TRANSFORMA TIONS/EQUILIBRIAALUMINUM ALLOYS TMS-AIME General Abstract Session Thursday, March 6, 1986 La Galerie 3 8:30 a.m. Marriott Hotel Session Chairman: A. D. Romig, Jr., Physical Metallurgy, Div. 1832, Sandia National Laboratories, P.O. Box 5800, Albuquerque, NM 87185
(8:30 a.m.) CLUSTER VARIATION CALCULATION OF STABLE AND METASTABLE EQUILIBRIUM IN AL-LI ALLOYS*: C.SIGLI and J.M. Sanchez, Henry Krumb School of Mines, Columbia University, New York, NY 10027, Stable and metastable phase equilibria in Al-Li alloys are investigated using a phenomenological free energy model. In this model, short range order in the solid phases is taken into account withi n the tetrahedron approximat.i on of the Cl uster Vari ati on Method. For the liquid phase, a subregular solution model is used. The energy parameters entering the free energy description
of each phase are determi ned by reproduc i ng s elected experi menta 1 thermodynamic data and equil ibrium concentrations in the phase diagram. The entire equil ibrium phase diagram is then computed. In addition, the metastable equilibrium between the Al-rich fcc solid solution and the A13Li phase is analyzed. A metastable miscibility gap is predicted to occur within the Al-rich solid solution below 400 K. *This work was funded by the National Science Foundation under grant #DMR-82-06195.
(8:50 a.m.) NUCLEATION ENTROPY AND PRECIPITATION BEHAVIOUR OF A1-Ti-Be ALLOYS: T. O. Lowes and W. V. Youdelis, Department of Engineering Materials, University of l.Jindsor, Windsor, Ontario, Canada, N9B 3P4. The role of nucleation entropy in the prec~pltatlon behaviour of AI-O.2wt%Ti-O.2wt%Be alloys is investigated. A higher precipitate particle density is observed in the AI-Ti alloys containing Be. The incorporation of Be into the peritectic TiAl3 compound
as Ti(Al,Be) 3 shown earlier, increases the nucleation entropy (~SV) and hence the nucleation rate of the compound according fo classical nucleation theory. The higher particle density for the AI-Ti-Be alloy is in agreement with the nucleation entropy model. Hardness and resistivity of the Al-Ti and Al-Ti-Be alloys were monitored for different aging temperatures. The investigations show an age hardening tendency only for the Al-Ti alloys containing Be.
(9: 10 a.m.) THE DETERMINATION OF PARTIAL STRUCTURE FUNCTIONS USING ANOMALOUS SMALL ANGLE X-RAY SCATTERING: J. J. Hoyt, B. Clark, M. Kraitchman, B. E. C. Davis, D. de Fontaine, Department of Materials Science and Mineral Engineering, University of Cal ifornia, Berkeley, CA 94720; O. Lyon, Laboratoire de Metallurgie Physique, University PARIS XI, OR SAY 91405, France
Small Angle Scattering spectra from Al-rich Al-Zn-Ag alloys at a series of energies near the Zn-absorption edge were obtained from the Stanford Synchrotron Radi at i on Laboratory. The corrected intensity vs. the relative change in the atomic scattering factor of zinc yields an expected quadratic form. The parameters of the fitted parabola give directly the values of the part i a 1 structure funct ions SZnZn( q), SZnAg( q), SAgAg( q). The results agree well with the "two phase model" of p~ase separation. In addition, scaling behavior of the three partial structure functions was examined.
(9:30 a.m.) UNMIXING KINETICS IN Al-Zn ALLOYS: B. Clark, J. P. Simon, J. J. Hoyt, R. Pro, Department of Materials Science and Mineral Engineering, University of California, Berkeley, CA 94720; O. Lyon, Laboratoire de Metallurgie Physique, University PARIS XI, ORSAY 91405, France Unmixing kinetics in Al-Zn alloys have been studied using small angle X-ray scattering at the Stanford Synchrotron Radiation Laboratory. Experiments were performed in situ using compositions of Al-12%(at)Zn, Al-22%(at)Zn, Al-32%(at)Zn. Due to the high counting rate obtainable from the synchrotron source, isothermal temperatures were reached in 40-50 sec with a data collection time of cel0 sec per spectrum. Results for the 22% and 32% samples show good agreement with Lifshitz-SlyozovWagner coarsen i ng beha v i or, whereas resu lts from the 12% samp 1e do not seem to fo 11 ow the L i fsh i tz-Sl yozov -Wagner power 1 aw relationship. Possible explanations for this anomaly wi 11 be discussed.
(9:50 a.m.) NUCLEATION OF Q', T1 AND C' ON A13Zr IN A1-Li-Cu-Zr ALLOYS: J. Galbraith. M. H. Tosten and P. R. Howell, Department of Materials Science and Engineering, The Pennsylvania State University. University Park, PA 16802. Transmission electron microscopy has been employed to determine both the nature of A13Zr (8') and its effect on the distribution of e I , Tl and 6'. For all three alloys investigated, 2.6 Li 1 Cu - 0.12 Zr, 2 Li - 3 Cu - 0.12 Zr, 1 Li - 4.5 Cu - 0.12 Zr, the S' acted as a nucleation/substrate for both S' and T l . In addition, nucleation of 8' on· 8' was observed in the first two alloys listed above. (0' was not present in the third alloy). For the plate-like phases, the low energy coherent face waS almost unvariably associated with the spherical S'. For the 6', nucleation followed by impingement and coalescence led to the formation of a 6' annulus on the S'. The efficiency of 13' as a nucleation substrate is discussed in terms of classical nucleation theory.
TMS Annual Meeting 127
(10: 10 a.m.) COflPARATlVE PRECIPITATION EFFECTS IN RAPIDLY SOLIDIFIED AI-Fe Ar;u AI-Fe-Ce ALLOYS; ~·1r. Eima) Kad, Haterials Science and Engineering, 421 Dougherty Hall, Univ. of TN 37996-2200 and Dr. Ben F. Oliver. Haterials Science and Engineering, 421 Dougherty Hall, Univ. of TN 37996-2200
Rapidly solidified AI-Fe alloys, with ternary additions are the subject of considerable interest for high temperature applications. Once such alloy AJ-8%Fe-3.4%Ce is currently being developed for high tempera ture applicat ions. In this study rapidly solidified Al-8%Fe and Al-8%Fe-3.4%Ce were produced by splat quenching. Thermal aging treatments were carried out for up to a bundred hours for temperatures between 300 and 400°C. Transmission microscopy studies of the precipitation effects will be reported. Results indicate a finer precipitate morphology and significant reduction in precipitate coarsening in the ternary alloy in comparison to the binary alloy for similar aging treatments.
(10:30 a.m.) DISCONTINUOUS COARSENING OF LAMELLAR DISCONTINUOUS PRECIPITATE IN AN Al-29 AT. PCT. Zn ALLOY: M. Shaarbaf and R.A. Fournelle, Department of flechanical Engineering, Marquette Universitv, Milwaukee, WI 53233 The growth kinetics of discontinuous coarsening of discontinuous orecipitate in an Al-29 at.% Zn alloy has been investigated over the temperature range from 323 to 523 0 K by light and scannine electron microscopy and x-ray diffraction. Lamellar discontinuous precipitation structures having a range of lamellar spacings and phase comDositions were formed by aging at temperatures ranQing from 323 to 523 0 K. These lamellar structures were subsequently i sotherma llv aged over the temperature ranee from 323 to 523 0 K and observed to di scontinuous ly coarsen. The growth rates, lamellar spacings, and phase compositions of the discontinuous coarsening cells were determined and analyzed according to the model of Petermann and Hornbogen. The growth rate of the cells was found to be controlled by grain boundary diffusion in the discontinuous coarsening cell interface.
(10:50 a.m.) THERMAL STABILITY OF RST Al-Ti-GO ALLOY, Y. Mahajan, S. D. Kirchoff, Materials Laboratory J Air Force Wright Aeronautical Laboratories, WPAFB, OH, 45433, and A. G. Jackson, Systems Research Laboratories, Inc., 2800 Indian Ripple Rd., Dayton, DH
45440. Rapidly solidified (RST) Al-4Ti-4Gd alloys, produced by melt spinning, were studied for thermal stability up to 600°C for 1 hr. Isochronal microhardness data for the alloy indicatets a slow increase in hardness with temperature and then a decrease at 500°C. Compared with Al-Fe-Ce, Al-Ii and Al-Gd alloys, the thermal stability is improved at high temperature. The combination of Ti and Cd in Al results in a promising combination of thermal stability due to the Ti and precipitate formation due to the Cd. Examination of the microstructures of the ternary alloy indicates that the as-solidified RST alloy possesses a dIspersion of fine precipitates which coarsen upon aging, producing a well developed precipitate/matrix morphology. Identification of the ternary compound is uncertain, but a modification of either Al3Gd or Al3Ti may play a role in the development of the compound. 'Work partially supported by AFIIAL Contract F33615-83-C-5073
(11: 10 a.m.) GROWTH OF 0' (AI3Li) PRECIPITATE FREE ZONES IN AI-Li ALLOYS. S. Jha and TH. Sanders, Jr., School of Materials Engineering, Purdue UniHrsity. West Lafayette, IN 47g07. The growth rat" of precipitate free zones (PFZ's) in AI·Li and AI-Li-Zi alloys WPre' IlH':1;.iurpd as a function of tim(\ te'mppraturc> and composition, ttw growth ratC' occurs by a solute dpplption m('chanisf!l and the solutr is ('onsumed by the growth of 0 particles at the boundaries. The PFZ's paraboli(·ally wilh tilll<' by an interface rontrolled mechanism. For containing zirconium. the PFZ width depends upon the nature of grain boundnry and the' distribution of fJ particles at various houndari('s. [[mn'Hr, the average I'FZ width also follows a parabolie rate law.
(11 :30 a.m.) QI'.-\0:TITATl\lo DESCRIPTION OF TilE MICROSTHI·CTPTlE I:'-i AI-Li ALLOYS. K. Mahalingam S. Jha and TIl. Sanders, Jr., Sehool of ~1at('rials Engineering, Purdue lInivprsity, West Lafayette, IN 4.g07 This paper d,",erilH's the results of a quantitative transmission electron miero~('()py in\'('stigation of thE' coarsening pro('('ss of thp n1('ta stable' 6' (AI3Li) phase, and the growth of 0' precipilate free zones (PFZ's) in a seri,'s of AI-Li alloys. Analytical expression relating the particle size disIribution, the first, seeond and the third moments of distribution, and the growth ratt' of til{' PFZ's Wf're defprminf'd as a function of timE', tprnprratlln' and lithium content. By tbing thf'sr analytical f'xpressions OTIc> is ablp to pn'dict a micro.structur(' bas('d upon the aging ('onditioll and
lithium ('ontpnt.
128TMSAnnuai Meeting
PHASE TRANSFORMATIONS - KINETICS TMS-AIME General Abstract Session La Galerie 3 Thursday, March 6, 1986 Marriott Hotel 8:30a.m. Session Chairman: W. C. Johnson, Carnegie-Mellon University, Metallurgical Engineering and Materials Science, 3325 Wean Hall, Pittsburgh, PA 15213
(8:30 a.m.) THE DECOMPOSITION KINETICS OF A SUPERSATURATED Ni-12.5at .%Si ALLOY STUDIED BY SANS: S. Pol at, C. Marsh and Haydn Chen, Dept. of Metallurgy and Mining Engineering, Univ. of Illinois, Urbana, I L 61801; and J. E. Epperson, Materi a 1 s Sc i ence and Technology Division, Argonne National Laboratory, Argonne, IL 60439. The kinetics of y' precipitation in a supersaturated Ni12.5at.%Si alloy has been previously studied by in-situ wide angle x-ray diffraction technique. ~all angle neutron scatteri ng (SANS) experiments usi ng a pul sed neutron source have been performed to suppl ement the x-ray results. SANS reveal ed the presence of a broad interference peak characteri zi ng some sort of long period modulation, for specimens annealed 505°C and 550°C. Two measurements taken at 400°C for 24 hrs and 200 hrs showed a peak only for 200 hrs anneal. The time dependence of the peak position, Qm' and the intensity maximum, 1m, has been obtained from the experimental spectra as Qm ~ t- a 1 and 1m ~ t a 2. Similar to Ihj x-ray results particle size, R, is found to vary as R ~ t 1 suggesting an Ostwald ripening process in accordance with Li fshitz-Slyozov-Wagner (LSW) theory.
(8:50 a.m.) THE COARSENING KINETICS OF GAMMA PRIME PRECIPITATES IN Ni-A1-Mo
ALLOYS:
J. G. Conley. M. E. Fine and J. R. Weertman, Dept. of
Materials Science & Engineering and Materials Research Center, Northwestern University, Evanston, IL 60201
In order to investigate the role of lattice disregistry in the coarsening of ordered dispersed phases, the ripening kinetics of Ni3A1 type (-/) precipitates were measured at 7SrPc in 85-10-5, 84-8-8, and 84-6-10 (a/o Ni-AI-Mo) alloys. Mo is known to partition to and increase the lattice parameter of the matrix thereby decreasing the 1.2% misfit which exists in binary Ni-Al alloys with y'. TEM dark field examination revealed a swift morphology change from spheres to cubes upon aging the alloy with the largest positive misfit (85-10-5, 6 . . . . 0.8/0). The alloys with higher Mo exhibited spherical precipitates out to long aging times. Plots of r: 3 vs. time showed that a slight reduction in the misfit from increasing the Mo from 8 to 10 a/o resulted in a twofold decrease in the coarsening rate constant indicating that the lattice disregistry has a significant effect on the ripening kinetics of the ordered gamma prime phase in the Ni-AI-Mo system.
(9: 10 a.m.) CELLULAR DISSOLUTION CONTROLLED BY BOUNDARY MIGRATION IN Pb-Sn ALLOY. Stephen Hackney, Institute for Materials Science, National Bureau of Standards, Gaithersburg, MD 20899, Duk N. Yoon, Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, Seoul, Korea, Francis S. Biancaniello, Metallurgy Division, National Bureau of Standards, Gaithersburg, MD 20899. Following the investigation of Tu and Turnbull, the kinetics of cellular growth and cellular dissolution in Pb-Sn alloy are ana lyzed in terms of the Cahn so 1 ut i on of the boundary di ffus i on equation. Quantitative SEM/EDS is used to measure concentration profiles on both sides of the dissolution boundary. The results of temperature cycl ing experiments undertaken to induce growthssolution-regrowth over the same region are also reported.
controlled by classical energy barrier.
nucleation events
without
strai n
*Work performed for the U.S. il'>partment of Energy by MartinMarietta Energy Systems Inc., under contract DE-AC05-840R21400
(9:50 a.m.) GRAIN BOUNDARY PRECIPITATION IN THE NICKEL BASE SUPERALLOY
X-750:
K. L. Zeik and P. R. Howell, Department of ?>faterials Science and Engineering, The Pennsylvania State University, University Park, PA
16802.
The Nickel-Base Superalloy X-7S0 is used in bolting applications in aggressive environments. Hence, the nature and distribution of grain boundary precipitation is of obvious importance. In the present investigation convention'3.1 transmission microscopy (CTEM) and analytical electron microscopy (AEM) have been employed to document the microstructures of the grain boundary regions and to correlate these microstructures with the response of the alloy to corrosive environments. SpeCifically, the distribution of the M23 C6 precipitates has been documented as a function of ageing temperature. ageing time at a given temperature and alloy chemistry. In addition, a study has been initiated to investigate the effect of the nature of individual grain boundaries on the precipitate distribution. Axis/angle pairs have been computed using low camera length convergent beam electron diffraction patterns. The occurrence of y' precipitate free zones has been correlated with the existence of chromimn depleted zones.
(10: 10 a.m.) THE EFFECT OF ELASTIC MISFIT ON OSTWALD RIPENING KINETICS:
*V.J. Laraia, **P.W. Voorhees, and *W.C. Johnson, **Metallurgical Engineering and Materials Science, Carnegie-Mellon University, Pittsburgh, PA 15213. **Metallurgy DiviSion, National Bureau of Standards, Gaithersburg, MD 20899. The governing equations of Ostwald ripening are presented in a form consistent with the thermodynamics of two-phase solid systems. Stresses that arise from transformation strain, compositional inhomogeneity and surface stress affect the conditions for local thermodynamic equilibrium and the governing equations. In the absence of compositional strains, the equations are isomorphic with the standard LSW formulation. The misfit and surface stress effects persist in the capillary length and boundary conditions and thus they influence the coarsening kinetics. An analysis of these equations allows comparison with experiment. This work is supported by the National Science Foundation and the Office of Naval Research.
(10:30 a.m.) GROWTH OF A MISFITTING COHERENT PRECIPITATE. V. J. Laraia*, P. W. Voorhees**, and W. C. Johnson*, (*) Metallurgical Engineering and Materials Science, Carnegie-Mellon University, Pittsburgh, PA 15213 (**) Metallurgy Division, National Bureau of Standards, Gaithersburg, MD 20899. Phase transformation kinetics are determined, in part, by the interfacial solute concentrations in the precipitate and matrix. The thermodynamics of stressed solids is used to determine the equil ibrium concentrations at the interface of a spherical coherent precipitate possessing a pure dilatational misfit with the matrix as well as different elastic coefficients than the matrix. These interfacial concentrations are then used as one boundary condition for the appropriate field equation to determine the growth rate of a coherent misfitting precipitate. It was found that when elastic effects are included, the growth rate of the precipitate, for the same supersaturation, can be as much as a factor of two larger than when elastic effects are ignored. The results of the calculations and details of the thermodynamics necessary to describe precipitate growth in solids will be discussed. This work is supported by the National Science Foundation and the Office of Naval Research.
(10:50 a.m.) COARSENING RESISTENCE OF TiC PRECIPITATES IN AUSTENITIC STEEL. W. Kesternich, Kernforschungsanlage Jiilich, Institut fur Festkorperforschung, Postfach 1913, D-5l70 Jclich, Fed. Rep. of Germany, presently at Oak Ridge National Laboratory.
THE SETA- TO-ALPHA PHASE TRANSFORMA TION I N A URAN I UM ALLOY*: ,. A. Vandermeer, Naval Research Laboratory, Washi ngton, DC 20375-5000 The behavior of the 8 to a phase transformation during ontinuous cooling was studied in uranium containing 359 ppm Si and 233 ppm Fe using dilatometry and metallography. For cooling between 0.01 K/s and 125 K/s the transformation was ali near functi on of the square root of the e. The '-.average interface mi gration rate during transformation at 50Kundercooling was 1.04 x 10- 4 m/s. The transformation activation energy was approximately 2/3 that for volume diffusion in uranium. The transformation enthalpy was 2655 J/mole. The results support the view that the transformation was a massive transformation and agreed with a theoretical model in which the transformation start was
The formation of TiC precipitates in an austenitic steel has been investigated by transmission electron microscopy. Precipitation in dislocation free matrix was found to be completely inhibited. By nucleation at preexisting dislocation networks high densities of finely distributed TiC precipitates were created ('\.. 5 nm average particle diameter). Investigation of precipitate growth as a ~unction of time and temperature showed that the TiC precipitates are extremely stable against coarsening up to 800°C ('\.0 8 run average particle diameter after 1000 h at 750°C). This resistance to overaging of very fine precipitates is of great practical importance for elevated temperature applications. Present growth and coarsening theories do not account for the observed time and temperature dependence of the precipitate size. A growth mechanism is proposed which is based on solute sweeping and atomic rearrangement during dislocation recovery.
TMS Annual Meeting 129
(11: 10 a.m.) A Multiple-Technique Examination of Spinodal Decomposition in Fe-28.6 Wt. % Cr-IO.6% Co." Stephen Spooner, Oak Ridge National Laooratory, Oak Ridge, 'IN 37831, and M. K. Miller and L. L. Horton, Oak Ridge National Laboratory, Oak Ridge, TN 37831 The structure of a spinodally decomposed Fe-28.6 wt % Cr-lO.6% Co alloy aged at 525°C has reen examined with small:'angle neutron scattering, atom probe field-ion microscopy and electron microscopy. The measures of characteristic distance in the microstructure derived from each technique have been compared. Excellent agreement between electron microscopy results and atom probe field ion microscopy results is found. Interpretation of the small-angle neutron scattering curves is made clearer by use of the results of the microscopy methods. A cross-over in the time power law is seen along with an increase with time of chromium content of the chromium-rich phase measured by the atom probe method which suggests a change in the mode in which decomposition proceeds. *Operated by Martin Marietta Energy Systems, Inc., for the U.S. Department of Energy under contract DE-ACOS-840R21400.
(11 :30 a.m.) Evidence for the Metastable Miscibility Gap 1n AI-Li from SmallAngle X-Ray Scattering. * S. Spooner, Oak Ridge National Lpooratory Oak Ridge, TN 37831, and D. 13. Williams and C. M. Sung, Department of Metallurgy and Materials Engineering, Lehigh University, Bethlehem, PA 18015. A set of 6.8 at. % Li AI-Li alloys aged at 126°C and a set of 9.4 at. % Li AI-Li alloys aged at 100°C were examined with smallangle x-ray scattering and electron microscopy. The course of aging in each alloy leads to the development of 6' (Al3Li) but the higher concentration alloy aged at lower temperature undergoes very rapid decomposition suggesting the almost immediate and complete rejection of solute from the matrix by some rapid mechanism. The lower concentration alloy by contrast indicates a slower development of decomposition product. The Significance of these observat ions re lat i ve to a newly ca lculated metas ta hIe ~hase diagram is discussed. Research sponsored by the National Science Foundation Grant No. DMR-7724459 through Interagency Agreement No. 40-636-77 with the U.S. Department of Energy under contract DE-AC05-840R21400 with Martin Marietta Energy Systems, Inc.
(11 :50 a.m.) Cu-Au-Pd PHASE DIAGRAM: K. Udo and K. Yasuda, School of Dentistry, Nagasaki University, Nagasaki, Japan, and H. Yamauchi, Dept. of Engineering Materials, University of Windsor, Windsor, Ontario, Canada, N9B 3P4. The cluster variation method in the tetrahedron approximation was utilized to obtain a useful phase diagram of the Cu-Au-Pd ternary system. Energy par~meters for Cu-Pd were determined taking into account some conditions such as 1) the theoretical critical, temperature (Tc) for CU3Pd agrees with the experimental value, 2) the theoretical Tc for CuPd (Llo) should be lower than the experimental Tc for CuPd (B2), and 3) the magnitude of the pairwise interaction should be larger than that for the Cu-Au system because Tc' s of ordered phases in the Cu-Au system rise as Pd is added. The magnitude of the pairwise interaction for the Au-Pd system should be smaller than that for Cu-Au since some experimental evidence has been obtained such that no ordered phases may exist near the Au-Pd side above 300°C. The ternary tetrahedron (four-body) parameters should be set at non-zero values to take into account the fact that an Ll2 ordered phase shows as Pd is added to CuAu3 solid solution.
RAPID SOLIDIFICATION TECHNOLOGY FOR TITANIUM ALLOYS IV: Alloy Development and High Temperature Sponsored by the TMS Heat Treatment Committee Thursday, March 6,1986 Mardi Gras D 8:30a.m. Marriott Hotel Session Chairmen: 1. A. Hall, TIMET, Henderson Technical Laboratory, P.O. Box 2128, Henderson, NV 89015; F. H. Froes, Air Force Wright Aeronautical Laboratories, Materials Laboratory, AFWALIMLLS, Wright-Patterson AFB, OH 45433
(9:00 a.m.) FUNDAMENTAL STUDIES OF THE MICROSTRUCTURE OF RAPIDLY SOLIDIFIED Ti3Al AND TigAI-Nb: K. R. Teal, Air Force Materials Laboratory, AFWAL/MLLS, Wright-Patterson AFB, OH 45433; A. G. Jackson, Systems Research Laboratories, Inc., 2800 Indian Ripple Road, Dayton, OH 45440; D. Eylon, Metcut-Materials Research Group, P.O. Box 33511, Wright-Patterson AFB, OH 45433; and F. H. Froes, Air Force Materials laboratory, AFWAL/MLLS, Wright-Patterson AFB, OH 45433 The microstructure of rapidly solidified (RS) Ti3Al, and Ti3Al with additions of Nb, were examined and compared to ingot product. The TigAl alloy exhibited ordering, with an antiphase domain size which was considerably smaller than that observed in ingot material. However, unexpectedly, the grain size was not noticeably smaller in the RS product. The RS Ti-Al-Nb microstructure consisted of equiaxed grains about 3-5 microns in size. Analysis of foils show that alpha, alpha2' and beta are present in the as-solidified alloys while alpha2 and beta are present in alloys aged at 900°C (l650°F) for 1 hr. These observations, and the effect of Nb additions, will be rationalized in terms of differences in cooling rate experienced by the RS and conventional product.
(9:25 a.m.) DISPERSION STRENGTHENING OF Ti 3 Al-BASED ALLOYS BY RAPID S. M. L. Sastrv, R. J. Lederich, SOLIDIFICATION PROCESS ING': and J. E. O'Neal, McDonnell Douglas Research Laboratories, P.O. Box 516, Dept. 224, Building 110, St. Louis, MO 63166 Fine incoherent dispersoids and large aspect ratio filamentary reinforcements in alpha2+beta matrix were produced by rapid solidification processing of Ti-AI-Nb alloys containing erbium oxide, carbon, and boron. Rapidly solidified specimens were prepared by electron beam melting and splat quenching of prealloyed rods. The thermal stability and coarsening kinetics of RSP microstructures were determined by transmission electron microscopic examination. The potential beneficial effects of RSP and dispersion strengthening in extending the useful temperature range of Ti3AI base alloys were assessed.
"Research
conducted under the McDonnell Douglas Corporation Independent Research and Development program.
(9:50 a.m.)
BREAK
(10: 1 0 a.m.) CHARACTERIZATION OF METAL MATRIX COMPOS ITES PRODUCED FROM RAPIDLY SOLIDIFIED TITANIUM ALLOY Fons: D. Eylon, Metcut-Materials Research Group, P.O. Box 33511. WrightPatterson AFB, OH 45433 and F. H. Froes. Air Force Wright Aeronautical Laboratories, Materials Laboratory, AFWAL/MLLS, Wright-Patterson AFB, OH 45433 Rapid solidification (RS) ribbon making methods such as melt spinning and melt extraction can be used to produce rapidly solidified foils suitable for use in metal matrix composites. The ultrafine grain size inherent in RS products leads to superplastic flow behavior allowing foil/fiber compaction at lower temperatures than normal leading to smaller fiber/matrix react ion zone and hence to improved mechanical propert ies. Preliminary experiments using pendant drop melt extraction (PDME) RS ribbons of Ti-6Al-4V. Beta III, and Ti3A1 demonstrated that full compaction and bonding can be achieved at temperatures as low as 1350°F with minimum reaction zone size. Compaction conditions and reaction zone characteristics will be presented and discussed.
(10:35 a.m.) DISLOCATION INTERACTIONS IN ALLOYS BASED ON Ti3Al: S.A. Skewes, D.G. Konitzer", H.L. Fraser 1l':pt. of r-'etallurgy, Univ. of Illinois, Urbana, Il 61801, ALCOA Technical Center, Alcoa Center, PA 15069
(8:30 a.m.) RARE
rare e<1rth elements h8vP bpE'n aririprl. The rpl8tivp effectiveness with which sever81 different rare earth elements form oxirlp dispersions in splat-quE'nched Ti-Al solid solutions was examineri, using Ti-Al-Er as a referencE'. Oxygpn content was carefully control[pri by the use of hiCJh purity alloy components anrl rontinuously gettp.red argon rlurinq arr meltinq <':Inri spl8t quenching. Quantit
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nTA~-.lJUr,,1-Al Ut"lINUi"i ALLOYS, D. [3. Snow cHld A. Ciamel, United Technologies Resparch Center, Silvrr Lane, Last H8rtforri, CT 061fJS
Signlfic8nt potenti81 exists for thp improvement of creep strenqth by dispersion strpnqtheninq In r8pirllv-solirlifiprJ tItanium ,dloys to which
The dislocation microstructures in deformed samples of alloys based on Ti3Al have been investigated. Firstly, the interaction between dislocations and a refined dispersion of rare earth oxide particles is being studied. The scale of the dispersion is such that the dislocations are expected to bypass the particles; indeed, preliminary results may be interpreted on this basis.
130 TMS Annual Meeting The possible effect of these dislocation interactions leading to dispersal of slip from coarse slip bands is being assessed. A second set of experiments involves a determination of the influence of Nb additions to Ti3Al on the activation of sources of c+a dislocations. Additions of 5-1OWt.% Nb have been made as s ubstTtut ions for Ti ina rc-me lted buttons of the a 1 umi n i de. Compression samples have been machined and subsequently deformed to -2% strain at room temperature, 300°C and 500°C, respectively. The dislocation substructure is being analyzed using transmission electron microscopy. (11 : 00 a. m. ) A COMPARISON BETWEEN THE MICROSTRUCTURES OF LASER SURFACE MELTED Ti ALLOYS CONTAINING EITHER ~r OR La: J.T. Stanley, S.A. Court, D.G. Konitzer+, M.H. Loretto, H.L. Fr~ser, Dept. of Metallurgy, Univ. of Illinois, Urbana, IL 61801, Dept. of Metallurgy, Univ. of Birmingham, Rirmingham, UK., +ALCOA Technical Center, Al coa Center, PA 15069 In this paper, the microstructures of rapidly solidified (RS) Ti alloys with Er and La additions are compared. RS Ti-Er (-0.7at%) samples consist of a supersaturated solid solution based on a-Ti. Subsequent aging (700°C/l hr) produces a refined dispersion (8-20 nm diameter) of Er203 precipitates. The oxides are of two types, exhibiting different orientation relationships and slightly different lattice parameters. These differences are explained on the basis of the mechanisms of precipitation of the particles. The RS La (- 0.9at%) alloy does not form a supersaturated single phase, but exhibits a refined dispersion of La particles (- 30-60 nm diameter). On subsequent aging, the structure changes from La to La203, presumably by internal oxidation. The mechanism of formation of microstructure in the La containing alloy is thought to involve a monotectic reaction.
REDUCTION TECHNOLOGY VII: Current Efficiency and Fluid Dynamics Sponsored by the TMS Light Metals Committee Thursday, March 6, 1986 Ponchartrain Ballroom D 8:30a.m. Sheraton Hotel Session Chairman: Alan Tabereaux, Reduction Laboratory, Reynolds Metal Co., Sheffield, AL 35660
(9:40 a.m.) CURRENT EFFICIEN:Y MEASUREMENIS IN HIGH AMPERAGE All.lMINIlM CELIS AT 1& ALUMINA o)OCENTRATIONS.
R. Huglen and T. Berge (NJrsk Hydro a.s, Karrr0Y Fabrikker, N-4265, aavik, NJrway), '!h. Mellerud and B. Lillebuen, (NJrsk Hydro a.s, IEsearch Centre, N-3901 POrsgrunn, NJrway. We have investigated the current efficiency behaviour of rroclern 175 kA prebaked cells with central pointfeeders, by continously measuring the carbon monoxide content of the anode gas. '!he results are discussed and interpreted in terms of a previously presented reaction rroclel for the back reaction between carbon dioxide and allDninilDn.
110:00 a.m.1 DISSOLUTION OF ALUMINIUM IN CRYOLITE-ALUMINA MELTS (SEE THROUGH CELL STUDIES): ~,L. Fan (Northeast Institute of
Technology, Shenyang, China), K. Grjotheim (University of Oslo, Oslo, Norway) In this paper we carried out experiments in a see-through cell, in order to observe the metal dissolution phenomenon and anode effect in cryolite-alumina melts. It was found that when the molten metal was cathodically polarized the rate of dissolution of metal would be greatly depressed, and that there was a jet action from the carbon anode during anode effect at higher voltage.
(10:30 a.m.) A PHYSICAL mDa FOR t-IELT FlDW 11\ HALL CELLS. J. W. Evans and S. Bannerjee, Dept. ~laterials Science and ~ljneral Eng mecring, University of California, Berkeley, CA 94720. A "cold" physical mouel lias 15een used to study the electromag-
netically driven flow that occurs in Hall cells. The model is one-twelfth scale and contains Wood's metal (mp 79°C). Passage of current (typically 700 amp.) through the Wood's metal results in its flow in a horizontal direction d.n a manner that is ~malo gous to the electromagnetically driven flow of metal and electrolyte in a real cell. Velocities have been measured in the model by means of the velocity probe developed by Vives and Ricou. The effects of cell changes and upsets (such as "cold" or missing anodes) have been detennined.
(8:30 a.m.) GAINING THAT EXTRA 2% CURRENT EFFICIENCY: B.J. Welch, Department of Chemical and Materials Engineering, University of Auckland,
New Zealand.
(10:55 a.m.)
Although electrochemical energy consumption is the most important feature. current efficiency is the performance index that creates the greatest excitement in smelting. Over the years fundamental
MEASUREMENT OF LIQUID METAL FLOW VELOCITIES IN ELECTROLYTIC CELLS: TEST OF THE IRON ROD METHOD: A. Pant, A. Langille, R. Roy and M. Wells, Alcan International Limited, Kingston, Ontario, Canada K7l 4Z4.
researchers have gained insights into the various causes for the lowering in current efficiency. but at times they have left behind them a sea of confusion - their greatest contribution has been in seeding ideas for practical improvements. With a difficult operation and cautious management implementation of these ideas has only been made on an incremental approach. the process innovators could only aim for gains of the order of 2% at a time. It was evident at the AIME symposium on aluminium in 1962 that many different paths existed for current efficiency gains. This paper reviews the various milestones that have led to the present level of up to 96% efficiency being achieved. Thus the best of tOday's technology suggests that we can only gain another 2% the last 2% belonging to the pot itself.
(9: 15 a.m.)
This study proves the validity of using the iron rod dissolution method to measure metal flow velocities in reduction cells. The relationship between mass loss and velocity in a flow geometry like that normally used for the iron rod calibrations (the rod stirring the water in a round tank) was compared with that obtained in a flow similar to that in an electrolytic cell (flow in a channel with water flowing past the rod) using a water/sugar rod simulation. The correlations detennined were linear and identical in the two geometries. It was established that the iron rod dissolution vs velocity calibration curves nonnally derived in a stirred tank could be used in reduction cell geometries for flow measurement. Velocities measured in an operating cell using the iron rod method were compared with those obtained from a 3-dimensional calculational model, using two turbulence models. The two calculations compared well with the measured values.
CURRENT EFFICIENCY AT SHORT ANODE-CATHODE DISTANCE IN ALUMINIUM ELECTROLYSIS. s. Rolseth, A. Solheim, J. Thonstad and
T. Mliftiioglu. Norwegian Institute of Technology, Trondheim, Norway. Current efficiency (CE) was determined as a function of anodecathode distance (ACD) by means of gas analysis, using the Pearson and Waddington equation. In laboratory cells the CE was independent of ACD down to '" 2 cm. At shorter distances the CE decreased markedly due to gas induced convection at the metalbath interface. Stirring the bath by means of an impeller rotating at constant speed lowered the CE to an increasing degree wi th dec reas ing ACD due to intens if ied convec t ion a t short ACD IS. Waves generated at the metal-bath interface by vertical movements of a plunger hadJa minor effect on CEo In 140 kA industrial cells the CE rem,iined practically constant when the anode was lowered to"" 2.5 cm ACD and it then dropped sharply. Also in th is case the drop was assoc iated with disturbance of the metal-bath interface, manifested as irregular and increasing wave ampl i tudes.
(11 :20 a.m.) USE OF IRON SHIELDS FOR CORRECTING LOCAL DISTURBANCES OF MAGNETIC FIELDS IN THE ELECTROLYTIC POTS: G. Degan, Aluminia S.P.A.,
Centro Tecnico Processi, C.P. 51, 09010 Portosucuso (CA) , Italy Iron shields have been used in order to compensate for magnetic disturbances in electrolytic cells situated at the end of the potrooms. The magnetic pattern and the fluidodynamic behaviour of cells in all asymmetric positions in the potroom have been analyzed with the help of computer programs. The results of the simulations have been compared with the measured performances of the cells operated in said positions. Then the magnetic shields have been designed and inserted in four test cells. The experience was successful. In this paper we present the results of the calculations and the industrial experience.
