Quenching temperature, °C

Number of passes during rolling

900 950 i000 1050 ii00 1150

22/16 20/13 17/13 20/13 20/13 18/15

Notes: i. The numerator gives the number of passes for VIF alloy and the denominator that for VIF + EBF alloy. 2. Soaking time at each temperature was 15 min. CONCLUSIONS i. After quenching from a temperature above 900°C the structure of Kh20N73YuM alloy is supersaturated solid solution. Recrystallization temperature for the alloy is 900°C, and alloy structure in relation to melting method is characterized by a different volume recrystallized matrix which is caused by the degree of prior deformation and metal purity. 2. Quenching of Kh20N73YuM alloy, independent of the degree of prior deformation, should be carried out at a temperature above 900°C with soaking for 15 min. The heat-treatment range for VlF + EBF alloy is bounded by the region 1000-1100°C, and a further increase in temperature leads to worsening of the ductility properties. For VIF alloy this range is I000-I150~C. LITERATURE CITED i. 2. 3. 4.

S.S. Gorelik, Recrystallization of Metals and Alloys [in Russian], Metallurgiya, Moscow (1978). I.I. Novlkov, Heat Treatment Theory for Metals [in Russian], Metallurgiya, Moscow (1978). S.I. Bulat, A. S. Tikhonov, and A. K. Dubrovin, Deformability of Structurally Inhomogeneous Steels and Alloys [in Russian], Metallurgiya, Moscow (1975). B . V . Molotilov (ed.), Precision Alloys (Handbook) [in Russian], Metallurgiya, Moscow (1974).

EFFECT OF DEFORMATION AND ANNEALING ON THE PROPERTIES OF ELINVARS AT 77-650°K A. V. Deryabin, B. N. Shvetsov, N. G. Chomova, and Yu. A. Chirkov

UDC 669.018.5:621.785.374:539.382.2

Elastic properties of alloys close in composition to industrial Elinvars have not been studied at low temperatures. In view of the fact that industry is currently experiencing a particular requirement for alloys with thermally stable elasticity over a wide temperature range, including the range 77-300°K, these studies are of particular interest. It is also important to reveal the mechanism of suppression for the AE(AE%)-effect in industrial Elinvars as a result of thermomechanical treatment (TMT). Until now it has not been clear whether it is possible to use for estimating the AE%-effect in Elinvar alloys expressions obtained in classical works [i] and [2] since direct verification of the validity of these expressions has not been carried out. Comprehensive studies of Elinvar alloy properties are necessary to resolve these questions.

Scientific-Research Institute of Applied Physics at Irkutsk State University. I.P. Bardin Central Scientific-Research Institute of Ferrous Metallurgy (TsNIIChERMET). Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 30, 35-37, December, 1983. 908

0026-0673/83/1112-0908507.50

© 1984 Plenum Publishing Corporation

6

GPa

3Pa

s]

z2o

~ ~

tgo

Z10

:-s4

,o

2od

"~_ ~

186

~o IJL

~

~..

~

~7~ f60

~o

300

500 T, °K a

foo

3oo

5oo T, ° K

;~

3oo

b

500 T,

K

c

~1 ioo

30o d s o o t

K '

Fig. 1. Temperature dependences for elasticity modulus after deformation and annealing at 300 (e), 500 (O), 700 (m), and 900°C (A) for alloys: a) 44NIOKh; b) 42N10Kh (Broken lines) and 42N5Kh (solid lines); c) 40NIOKh (broken lines) and 40NbKh (solid lines); d) 38NIOKh (broken lines) and 38N5Kh (solid lines). D,~m

~r,MPa//~,

2>-- ~_.~# ~

O,9

~MI~ T

kA/m

I

f20

0,6 ~'~"~'

-- 80 '\

od ~0

500 ZOOTann' °C

I TRM

J

~o

SOO 500 ZOOTann, %]

Fig. 2. Dependence of average block size D, internal stresses of, coercive force Hc, and thermoremanent magnetization TRIM for alloys 44NIOKh (i), 38NIOKh (2), 42N5Kh (3), and 38N5Kh (4) on post-deformation annealing temperature. Results are given in this article for determination of elastic and magnetic properties, and internal stresses (x-ray method) in polycrystalllne alloys 44NIOKh, 42NIOKh, 40NIOKh, 38N10Kh (close in composition to strain aging Ellnvar 36Nq
909

TABLE i

Alloy

% T

\ t~

GPa m

44NIOKh 38NIOKh 42NSKtl 38NSKh

9,6 5,3 13,5 9,8

4,2 1,8 3,I 4,3

28 I~ 16

187 190 163 161

0,35 0,13 0,18

0,20

*Data of [7]. For worked specimens of Fe--Ni--Cr alloys (annealed at 300 and 500°C) temperature dependences for elasticity modulus in the range 77-650°K are similar to E(T) curves for Fe-Ni alloys in the magnetic saturation state [4]; a minimum below the Curie point (Tc) is only observed for alloys 40N5Kh and 38N5Kh (see Fig. i). For the rest of the test alloys in the worked condition, a break in the E(T) curve is only observed close to the T c point, and at temperatures below T c the dependence of elasticity modulus on temperature is practically linear. The recrystallization process leads to a marked change in the form of the E(T) relationship; at temperatures below T c for all of the test alloys a minimum is observed in elasticity modulus (see Fig. i). With a reduction in nickel and chromium content in the alloy, this minimum becomes more clearly defined and it moves into the region of lower temperatures. For specimens of alloy 38N5Kh annealed at 300 and 900°C the elasticity modulus minimum apparently corresponds to a temperature below 77°K (see Fig. id). The minimum elasticity modulus for alloys close to the composition of Invar 36N apparently corresponds to the temperature of 40-50°K since in this temperature range for alloy 36N a minimum in shear modulus is observed [5] (the form of the temperature dependences for elasticity modulus and shear modulus for Fe--Ni alloys is the same [4]). It was shown [6, 7] that the effect of deformation and subsequent annealing on elasticity modulus for ferromagnetic Ellnvars is mainly governed by the change in values of Ep and E l in the expression [8] E = Ep + AE A + A ~ + AE~,

(i)

where Ep is value of elasticity modulus obtained by extrapolating the E(T) relationship into the temperature region T > Tc; AE A is exchange contribution which is governed by the change in bonding energy with ferromagnetic ordering (for Invar type alloys it is anomalously large [4, 8]); AE~ is a relatively large change in the exchange contribution with application of a magnetic field or external stresses in the paraprocess region (for alloy 36N the value of AEw is about 2% of AE m = E -- Ep [9]; AE l ("bE-effect") is a value connected with the change in domain structure under the influence of an external stress applied during measurement of elasticity modulus. A reduction in Ep is caused by weaking of the texture (created during plastic deformation [6]) during post-recrystallization annealing; due to the fact that E >E> EO00> , the value of E decreases at all temperatures. With plastic deformation the contribution of AE l is almost completely suppressed [6, 7], and post-recrystalllzation annealing leads to a sharp reduction in it. At temperatures below T c absolute values AE A and AE l are at a maximum (for Fe-Ni--Cr Ellnvars AE l, AE A < 0 [i, 2, 4, 8]), and in different temperature ranges. Deformation and annealing have a marked effect on the relative values of contributions AE A and AE%, and consequently on the depth and position of the minimum in the E(T) curve. Independent of remagnetization mechanisms the value of AE l may be determined from the relationship [I, 2]

AE~=C~

%sE~ oi

'

(2)

where %s is magnetostriction for technical saturation; E s is elasticity modulus in the technical saturation state; of is average value of internal stresses; C~ is a constant equal to 2/5 in the case when the AEl-effect is determined by rotation of magnetization vectors

910

TABLE 2

z

(4

111,

,K*)

and 115 when AEh i s determined by a s h i f t o f n o t l e s s t h a n -180'

interdomain boundaries

(:- - h S a s < K A )

for

[ 2 ] ; KA i s c r y s t a l l o g r a p h i c a n i s o t r o p y c o n s t a n t .

X-ray d e t e r m i n a t i o n of v a l u e s f o r i n t r a b l o c k s t r e s s e s of made i t p o s s i b l e f o r u s t o c a r r y o u t f o r t h e f i r s t t i m e d i r e c t v e r i f i c a t i o n of t h e K e r s t e n - B e c k e r D o r i n g Eq. (2) f o r t h e AEi-effect. C o n s i d e r a t i o n w a s g i v e n t o t h e f a c t t h a t t h e AEk-effect i n t h e deformed s t a t e ( a f t e r a n n e a l i n g a t 300°C) i s v e r y s m a l l , and i t was t a k e n t o e q u a l t h e v a l u e of t h e AEi-effect a f t e r quenching from 900°C i n w a t e r (800 and 1300 MPa f o r a l l o y s 38N5Kh and 42N5KhY r e s p e c t i v e l y [ 7 ] ) . These v a l u e s were summed w i t h t h e d i f f e r e n c e of AEm v a l u e s a f t e r a n n e a l i n g a t 900 and 300°C ( t h e change i n AEA and AE, d u r i n g a n n e a l i n g d i d n o t exceed t h e l i m i t s of measurement e r r o r s [ 7 ] ) . A s a r e s u l t of t h i s v a l u e s of AEl were o b t a i n e d c o r r e sponding t o a n n e a l i n g a t 900°C, and t h e v a l u e of c o n s t a n t C1 i n Eq. ( 2 ) was determined ( T a b l e 1 ) . C a l c u l a t e d v a l u e s of C1 = 0.13-0.35 a r e i n s a t i s f a c t o r y agreement w i t h t h e res u l t s o f t h e o r e t i c a l (C1 = 0.2-0.4 [ I , 21). For t h e m a j o r i t y of a n n e a l e d specimens v a l u e s o f C1 were c l o s e t o 115, and t h i s i n d i c a t e s t h e predominant c o n t r i b u t i o n of d i s p l a c e m e n t I n worked a l l o y s ( n o t l e s s t h a n -180") f o r i n t e r d o m a i n b o u n d a r i e s i n t h e AEl-effect. boundary movement i s much more d i f f i c u l t mainly due t o t h e i n c r e a s e i n t h e l e v e l o f i n t e r n a l s t r e s s e s o f , and t h i s i s i n d i c a t e d by t h e i d e n t i c a l n a t u r e o f r e l a t i o n s h i p s of(Tann) and Hc(Tann

Fig. 2

Comparison of m a g n e t o e l a s t i c energy d e n s i t y

and c r y s t a l l o -

g r a p h i c a n i s o t r o p y c o n s t a n t s KA i n d i c a t e ( T a b l e 2) t h a t i f a f t e r r e c r y s t a l l i z a t i o n (anneali n g a t 900°C) t h e c o n t r i b u t i o n of t h e s h i f t ( n o t l e s s t h a n -180°C) f o r i n t e r d o m a i n b o u n d a r i e s t o t h e A l l - e f f e c t predominates

3

)

t h e n i n worked a l l o y s ( a n n e a l e d n t 300 and

500°C) c o n t r i b u t i o n s connected w i t h boundary movement and r o t a t i o n of m a g n e t i z a t i o n v e c t o r s a r e comparable CONCLUSIONS

1. A change i n t h e form of t e m p e r a t u r e dependence f o r e l a s t i c i t y modulus o f Fe--Ni-Cr E l i n v a r s w i t h a change i n t h e i r composition b o t h under t h e a c t i o n of d e f o r m a t i o n and anneali n g p o i n t s t o t h e p o s s i b i l i t y of c r e a t i n g a n a l l o y w i t h t h e r m a l l y s t a b l e e l a s t i c i t y o v e r a wide t e m p e r a t u r e r a n g e i n c l u d i n g t h e r a n g e 77-300°K.

2. It is possible to use the Kersten--Becker--Doring equation to estimate the value of the AEk-effect in Elinvars. With standard treatment for Elinvar 36NKhll (drawing with the level of deformation at 60%, annealing at 500°C [3]) the contribution to the AEk-effect of movement (not less than --180°) of interdomain boundaries and magnetization vector rotation is approximately the same. LITERATURE CITED i. 2. 3. 4. 5. 6.

7.

8. 9.

M. Kersten, Z. Phys., 85, 708-716 (1933). R . B . Becker and R. DDring, Ferromagnetism, Berlin (1939). Precision Alloys (Handbook) [in Russian], Metallurgiya, Moscow (1974), PP. 395-408. E. Torok and G. Hausch, "Bulk modulus anomaly of Fe--Ni and Fe--Pt Invar alloys," Phys. Status Solidi (a), 53, 147-151 (1979). H. Ledbetter, "Elastic constant at low temperature," Adv. Cryogenic Eng., 24, 103-119 (1978). A . M . Tseitlin and V. Ya. Zubov, "Effect of plastic deformation and subsequent heat treatment on Young's modulus and crystallographic texture for Fe-Ni--Ti alloys of the Invar type," Fiz. Met. Metalloved., 22, No. 5, 780-785 (1966). O . A . Khomenko, A. M. Tseitlin, and G. A. Tarnovskii, "Effect on quenching on the Young's modulus anomaly for binary and alloy Invars," Fiz. Met. Metalloved., 30, No. 4, 769-773 (1970). G. Hausch and H. Warlimont, Z. Metallkunde, 64, No. 3, 152-159 (1973). V . M . Kalinin, O. A. Khomenko, and Z. E. Dubnik, "The nature of Invar anomalous elasticity," in: Physics of Metals and Their Compounds [in Russian], Vol. 2, Ural. State Univ., Sverdlovsk (1974), pp. 131-137.

EFFECT OF SULFUR ON STRUCTURE AND PROPERTIES OF Fe--Ni--Cr-BASED DISPERSION HARDENING ALLOYS V. A. Strizhak, S. I. Stepanov, V. V. Kiselev, I. A. Gorlach, O. A. Khomenko, and N. V. Kas'yanov

UDC 669.018.2-157:546.22

In accurate instrument building there is extensive application of precision Fe--Ni--Crbased alloys strengthened with 7'-phase whose insufficient machinability reduces the possibility of using automatic lathes. Analysis of data in the literature on microadditions to steels and alloys with the aim of increasing cutting tool life indicates that low-melting point elements, e.g., tin, are only desirable for a certain group of steels. Increased calcium concentration, which mainly alters nonmetallic inclusion morphology, may lead to a complete loss of hot ductility for highly alloyed materials with intermetallic strengthening which are difficult to work [I, 2]. Among the chalcogens researchers have recently shown a preference for selenium and tellurium which provide a favorable shape for manganese chalcogenides in normal steels, and they have almost no deleterious effect on the properties of materials including corrosion resistance [i, 7]. However, in the structure of precision alloys with a high titanium content (more than 2%), which has a greater affinity for sulfur than manganese, manganese sulfide is not detected. This is confirmed by the results of x-ray microanalysis of inclusions in industrial melts carried out by the authors in a previous article. In view of this it is of interest to add to similar alloys the traditional, inexpensive chalcogen of lowest toxicity, i.e. sulfur. In addition, it is indicated in [3] that sulfides with a hexagonal lattice, which relates to titanium sulfide, are effective lubricants whose lubricating properties are due to a layered structure. Translated from Metallovedenie i Termicheskaya Obrabotka Metallov, No. 12, pp. 37-39, December, 1983.

912

0026-0673/83/1112-0912507.50

© 1984 Plenum Publishing Corporation