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Submitted on 1 Jan 1982
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COHERENCY OF THE TRANSFORMATION STRAIN AT THE GRAIN BOUNDARY AND
FRACTURE IN Cu-Zn-Al ALLOY
K. Takezawa, T. Izumi, H. Chiba, S. Sato
To cite this version:
K. Takezawa, T. Izumi, H. Chiba, S. Sato. COHERENCY OF THE TRANSFORMATION STRAIN
AT THE GRAIN BOUNDARY AND FRACTURE IN Cu-Zn-Al ALLOY. Journal de Physique Col-
loques, 1982, 43 (C4), pp.C4-819-C4-824. �10.1051/jphyscol:19824134�. �jpa-00222120�
COHERENCY OF THE TRANSFORMATION STRAIN AT THE GRAIN BOUNDARY AND FRACTURE IN Cu-Zn-A1 ALLOY
K. Takezawa, T. Izumi, H. Chiba and S. S a t o
Department of AppZied Physics, FucuZty of Engineering, Hoklcaido University, Sapporo, 060, Japan
(Accepted 9 August 1982)
A b s t r a c t . - Two t y p e s o f Cu-Zn-A1 b i c r y s t a l specimens h a v i n g e / a z l . 4 , o n e w i t h t h e boundary p a r a l l e l t o and t h e o t h e r p e r p e n d i c u l a r t o t h e t e n s i l e d i r e c t i o n , were extended a t room t e m p e r a t u r e . The morphological change n e a r t h e boundary was c o n t i n u o u s l y observed by a microscope w i t h a VTR d u r i n g t h e e x t e n s i o n . For a p a r t i c u l a r o r i e n t a t i o n w i t h r e s p e c t t o t h e t e n s i l e d i r e c - t i o n , t h e same v a r i a n t c r y s t a l o f 6; m a r t e n s i t e a s t h a t which would be s t r e s s - i n d u c e d i n a n i n d i v i d u a l component c r y s t a l i s produced w i t h t r a n s f o r - mation s t r a i n s which o c c a s i o n a l l y c o n t i n u e a c r o s s t h e boundary. However, a d i f f e r e n t v a r i a n t c r y s t a l from t h a t i n t h e i n d i v i d u a l component c r y s t a l i s u s u a l l y formed n e a r t h e boundary depending on t h e o r i e n t a t i o n o f t h e o t h e r g r a i n . T h i s v a r i a n t h a s a n o r i e n t a t i o n such t h a t t h e s t r a i n f i e l d s c o i n c i d e w i t h t h o s e produced by a v a r i a n t which i s t r a n s f o r m e d s i m u l t a n e o u s l y i n t h e o t h e r g r a i n n e a r t h e boundary. S i n c e t h e p o s s i b l e number of s h e a r systems p r o d u c i n g t h e i n t i m a t e 6i v a r i a n t s i n b o t h g r a i n s i s l i m i t e d , t h e f r a c t u r e t a k e s p l a c e o f t e n a t t h e g r a i n boundary. However, when a: m a r t e n s i t e s a r e formed a t t h e boundary, a s f r e q u e n t l y o b s e r v e d , t h e f r a c t u r e is s u p p r e s s e d t o a g r e a t e x t e n t , b e c a u s e of i n c r e a s i n g numbers of independent s h e a r systems.
Consequently, t h e d e g r e e o f e a s e o r d i f f i c u l t y i n p r o d u c i n g a: m a r t e n s i t e s i s c l o s e l y a s s o c i a t e d w i t h t h e c h a r a c t e r of f r a c t u r e i n Cu-Zn-Al a l l o y . An extended work on f r a c t u r e u s i n g p o l y c r y s t a l l i n e specimens o f d i f f e r e n t e / a v a l u e s a l s o s u p p o r t e d t h e above r e s u l t s .
I n t r o d u c t i o n . - The mechanical b e h a v i o r a s s o c i a t e d w i t h t h e s h a p e memory e f f e c t and p s e u d o e l a s t i c i t y i n p o l y c r y s t a l l i n e Cu-base m a r t e n s i t i c a l l o y s i s remarkably a f f e c t - ed by t h e s i z e and c r y s t a l l o g r a p h i c o r i e n t a t i o n s of t h e i n d i v i d u a l g r a i n s [ l , 21.
T h i s i s b e c a u s e t h e g r a i n boundary h a s t h e l i f e - a n d - d e a t h power o v e r t h e r e v e r s i - b i l i t y of m a r t e n s i t i c t r a n s f o r m a t i o n and t h e r e f o r e t h e i n v e s t i g a t i o n c o n c e r n i n g t h e e f f e c t of boundary[3, 41 i s u n a v o i d a b l e work p r i o r t o t h e i n d u s t r i a l u s e o f t h e s e phenomena. I n t h e p r e s e n t work a d e t a i l e d morphological e x a m i n a t i o n was performed on v a r i o u s b i c r y s t a l s of Cu-Zn-A1 a l l o y s w i t h d i f f e r e n t o r i e n t a t i o n s of compo- n e n t c r y s t a l s . A t t e n s i o n was paid t o t h e s t r a i n c o m p a t i b i l i t y of t h e s t r e s s - i n d u c e d
F i g . 1 Two t y p e s of b i c r y s t a l t e n s i l e specimens.
( a ) Type A ( e q u i - s t r a i n ) ( b ) Type B ( e q u i - s t r e s s ) .
Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphyscol:19824134
C4-820 JOURNAL DE PHYSIQUE
m a r t e n s i t e a t t h e boundary. As r e p o r t e d s o f a r [ 5 ] , s i n c e t h e t r a n s f o r m a t i o n p r o - c e e d s by two s t e p s i n t h i s a l l o y s y s t e m , i . e . , B1+Bi+cii, t h e b e h a v i o r o f n o t o n l y
B i
b u t a l s o c i i m a r t e n s i t e s h a s b e e n s t u d i e d i n r e l a t i o n t o t h e f a c t u r e a t t h e boun- d a r y .E x p e r i m e n t a l p r o c e d u r e . - I n g o t s o f Cu-Zn-A1 a l l o y s w i t h v a r i o u s c o m p o s i t i o n s were p r e p a r e d f r o m h i g h p u r i t y Cu, Zn and Al b y m e l t i n g a t 1 3 7 3 K i n a r g o n f i l l e d s i l i c a c a p s u l e s . The m e l t s were s l o w l y c o o l e d t o 1 1 4 3 K and homogenized f o r 1 h r a t t h i s t e m p e r a t u r e , f o l l o w e d by q u e n c h i n g . The g r a i n s i z e o f t h e i n g o t was l a r g e enough t o p r e p a r e b i c r y s t a l t e n s i l e s p e c i m e n s . Two t y p e s o f b i c r y s t a l s p e c i m e n s , o n e w i t h t h e b o u n d a r y p a r a l l e l t o ( t y p e A, e q u i - s t r a i n ) and t h e o t h e r p e r p e n d i c u l a r t o ( t y p e B , e q u i - s t r e s s ) t h e t e n s i l e d i r e c t i o n were c u t from t h e i n g o t by a s p a r k machine a s shown i n F i g . 1. The c o m p o s i t i o n s o f a l l o y s were set s o a s t o k e e p t h e M s tem- p e r a t u r e c o n s t a n t , i . e . 260 K , u s i n g a n e m p i r i c a l f o r m u l a o f Ms(K)=3350-ROCZ-llOCA, where C Z a n d C a r e t h e c o n c e n t r a t i o n o f Zn and Al, r e s p e c t i v e l y . P o l y c r y s t a l l i n e
A
t e n s i l e s p e c i m e n s w i t h d i f f e r e n t c o m p o s i t i o n s were a l s o p r e p a r e d . The morphologi- c a l change n e a r t h e boundary was c o n t i n u o u s l y o b s e r v e d by a m i c r o s c o p e w i t h a VTR d u r i n g t h e e x t e n s i o n o f t h e s p e c i m e n by a n I n s t r o n t y p e machine, t h e s t r e s s - s t r a i n c u r v e b e i n g r e c o r d e d a s w e l l .
Strain ( % )
F i g . 2 S t r e s s - s t r a i n c u r v e f o r a Type A b i c r y s t a l s p e c i m e n o f Cu-31.6at%
Zn-4.2at%A1 a l l o y . The t e n s i l e d i r e c t i o n s a r e [ 9 z y ] and 152 0 1 , f o r component c r y s t a l s , r e s p e c - t i v e l y .
P h o t o . 1 Change i n m a c r o g r a p h i c s t r u c t u r e upon l o a d i n g . The m a c r o g r a p h s were t a k e n a t t n e p o i n t s numbered i n F i g . 2 .
where macrographs were t a k e n f o r t h e morphological e x a m i n a t i o n a s shown i n Photo. 1.
As c l e a r l y o b s e r v e d i n Photo. 1, a s soon as a
6;
v a r i a n t was induced i n t h e bottom g r a i n , G2, a t t h e p o i n t ( 2 ) , a n o t h e r6;
appeared i n t h e o t h e r g r a i n , G I , and t h e s e 6; v a r i a n t c r y s t a l s i n b o t h g r a i n s grew c o o p e r a t i v e l y w i t h a s i m i l a r r a t e up t o (5).A t (7) t h e f i r s t t r a n s f o r m a t i o n was completed i n G 1 and t h e second one,
~ i - w i ,
s t a r t e d t o a p p e a r i n
6;
w i t h new t r a c e s , and a s i n c r e a s i n g s t r e s s t h e number o f a ; t r a c e s was i n c r e a s e d i n b o t h g r a i n s . Moreover, one s e e s zig-zag s l i p l i n e s i n G 1 n e a r t h e boundary a t ( 9 ) . These l i n e s l o c a t e o n l y n e a r t h e boundary even a t h i g h e r s t r e s s l e v e l ( 1 1 ) .The most i m p o r t a n t f e a t u r e i n t h i s t y p e of morphological change i s t h a t t h e r n a r t e n s i t i c t r a n s f o r m a t i o n d o e s n o t t a k e p l a c e i n d e p e n d e n t l y i n b o t h g r a i n s b u t pro- c e e d s w i t h s t r o n g i n t e r f e r e n c e a c r o s s t h e boundary. T h i s is caused by a n e c e s s a r y c o n d i t i o n a s s o c i a t e d w i t h t h e c o m p a t i b i l i t y of t r a n s f o r m a t i o n s t r a i n s a t t h e g r a i n boundary. When t h e c o n d i t i o n can n o t be f u l f i l l e d c o m p l e t e l y , a s l i p d e f o r m a t i o n must b e o p e r a t e d a s s e e n i n Photo. l ( 9 ) . The c o n d i t i o n of s t r a i n c o m p a t i b i l i t y i s t o have t h e same v a l u e o f s t r a i n components, eUU, E- and y i n b o t h g r a i n s f o r
uw
t y p e A ( e q u i - s t r a i n ) specimen and o f E and yvw f o r t y p e B ( e q u i - s t r e s s ) v v Y €WW
specimen, r e s p e c t i v e l y , when we t a k e u , v and w a x e s a s shown i n F i g . 1 [ 6 , 71.
Photo. 2 i s a macrograph showing homogenuously d i s t r i b u t e d
6;
m a r t e n s i t e i n b o t h g r a i n s . The specimen c o n t a i n s 4.2at%Al a s weLl2 and t h e t e n s i l e d i r e c t i o n s of component c r y s t a l s , G_1 and G2, a r e [ 5 4 1 ] and [1310-21, r e s p e c t i v e l y . Two v a r i a n t c r y s t a l s , h a v i n g ( 1 2 2 1 1 ) h a b i t p l a n e i n G 1 and (12 2 1 1 ) i n G2 s t i c k t o g e t h e r one by one a t t h e boundary. The s t r a i n components, E e and y a r e c a l c u l a t e d t o beuu' WW uw
'
0.075x, - 0 . 0 2 1 ~ and - 0 . 0 4 1 ~ f o r t h e f i r s t m a r t e n s i t e i n G I and 0.069x, - 0 . 0 1 9 ~ and - 0 . 0 5 3 ~ f o r t h e second one i n G2, r e s p e c t i v e l y , where x means t h e f r a c t i o n a l volume of
6;.
One s e e s v e r y good s t r a i n c o m p a t i b i l i t y i n t h i s c a s e . I t i s i n t e r e s t i n g t h a t a c a l c u l a t i o n d e r i v e s _ a s m a l l e r v a l u e of Schmid f a c t o r , 0 . 3 7 , f o r t h e v a r i a n t appeared i n G2 h a v i n g ( 1 2 2 1 1 ) h a b i t p l a n e t h a n t h a t o f 0.39 f o r a v a r i a n t h a v i n g( 1 2 2 1 1 ) h a b i t p l a n e . T h i s means t h a t a d i f f e r e n t v a r i a n t from t h a t which would be s t r e s s - i n d u c e d i n G2 was transformed by t h e s t r a i n c o m p a t i b i l i t y a t t h e boundary.
Photo. 2 A macrograph showing homogeneously d i s t r i b u t e d
6;
m a r t e n s i t e s i n b o t h g r a i n s of t y p e A s p e c i - men. They meet one by one a t t h e boundary.C4-822 JOURNAL DE PHYSIQUE
Photo. 3 A macrograph showing complex s t r u c t u r e neaf- t h e boundary. D i f f e r e n t v a r i a n t c r y s t a l s o f B1 m a r t e n s i t e from t h o s e w i t h maximum Schmid f a c - t o r were induced n e a r t h e boundary i n b o t h g r a i n s . a; m a r t e n s i t e s a r e a l s o s e e n .
A more s t r i k i n g example o f _ t h e above phenomenon i s r e p r e s e n t e d i n Photo. 3 . The t e n s i l e d i r e c t i o n s were [ 9 4
1 1
and [ 4 7 1 ] f o r G 1 and G2, r e s p e c t i v e l y . I n i t i a l - l y , a s m a l l amount ofB i
m a r t e n s i t e s having maximum Schmid f a c t o r s , i . e . , w i t h ( 1 2 1 1 1 ) h a b i t p l a n e s , were i n t r o d u c e d i n b o t h g r a i n s e x c e p t n e a r t h e boundary. However, s i n c e t h e s h e a r components of t h e t r a n s f o r m a t i o n s t r a i n of t h e s e m a r t e n s i t e s were q u i t e d i f f r e n t i n b o t h g r a i n s , i . e .,
- 0 . 0 0 6 ~ i n G 1 and 0 . 0 4 4 ~ i n G2, a new v a r i a n t o f 5; m a r t e n s i t e h a v i n g ( 1 2 1 1 7 ) h a b i t p l a n e , which had y =0.027x, a p p e a r e d n e a rUW
t h e boundary i n s t e a d o f t h e f o r m e r one i n G 1 and grew w i t h i n c r e a s i n g a p p l i e d s t r e s s . Furthermore, f o l l o w i n g t o t h e growth of t h i s v a r i a n t , t h e second t r a n s f o r - mation ~;+ai t o o k p l a c e a t t h e boundary i n G2 a s s e e n i n Photo. 3.
The b e h a v i o r o f s t r e s s - i n d u c e d t r a n s f o r m a t i o n i n b i c r y s t a l of t y p e A (equi- s t r a i n ) i s s t r o n g l y a f f e c t e d by t h e g r a i n boundary a s d e s c r i b e d above. On t h e o t h e r hand, i n t h e c a s e of t y p e B b i c r y s t a l , t h e component c r y s t a l s b e h a v e a s i f each c r y s - t a l were i n d i v i d u a l l y e l o n g a t e d , e x c e p t t h e r e g i o n n e a r t h e boundary. So t h a t , i n t h i s c a s e t h e v a r i a n t c r y s t a l o f 6; m a r t e n s i t e was t h e same a s t h a t i n a s i n g l e c r y s t a l of e a c h component and t h e s t r e s s - s t r a i n c u r v e becomes simply a superposed c u r v e of t h e two i n d i v i d u a l s t r e s s - s t r a i n c u r v e s of component c r y s t a l s . At t h e g r a i n boundary, e x c e p t f o r a p a r t i c u l a r o r i e n t a t i o n r e l a t i o n between two component c r y s t a l s , complex m o r p h o l o g i c a l b e h a v i o r s a r e g e n e r a l y observed by t h e s t r a i n com- p a t i b i l i t y . I n b i c r y s t a l specimens w i t h 31.6at%Zn and 4.2at%A1, a s t h e a p p l i e d s t r e s s was i n c r e a s e d , t h e a; m a r t e n s i t e s were q u i t e o f t e n observed n e a r t h e g r a i n boundary w i t h a number o f s l i p t r a c e s i n s i d e . However, c r a c k s were formed e a s i l y a t t h e boundary f o r specimens c o n t a i n i n g h i g h e r A 1 c o n t e n t s , independent o f t h e t y p e of b i c r y s t a l , i n which t h e second t r a n s f o r m a t i o n was h a r d l y g e n e r a t e d .
I n Fig. 3 a r e shown s t r e s s - s t r a i n c u r v e s up t o f r a c t u r e f o r specimens o f s i n g l e c r y s t a l , b i c r y s t a l and p o l y c r y s t a l o f two k i n d s o f a l l o y w i t h d i f f e r e n t A1 c o n t e n t s . The c u r v e ( a ) o b t a i n e d f o r a s i n g l e c r y s t a l o f 4 . 2 a t % A l a l l o y i n d i c a t e s a l a r g e e l o n g a t i o n o f 20% c o r r e s p o n d i n g t o t h e S1+f3i+ai t r a n s f o r m a t i o n which was followed by an a d d i t i o n a l 255: p l a s t i c d e f o r m a t i o n by s l i p i n t h e m a r t e n s i t e . The s u r f a c e o f f r a c t u r e showed a t y p i c a l p a t t e r n o f t h e d u c t i l e f r a c t u r e . The c u r v e ( b ) was recorded f o r a specimen o f t y p e A b i c r y s t a l h a v i n g a p a r t i c u l a r o r i e n t a t i o n r e l a t i o n o f component c r y s t a l s s u c h t h a t t h e 6; m a r t e n s i t e s w i t h maximum Schmid f a c t o r i n - duced i n b o t h g r a i n s were w e l l connected w i t h e a c h o t h e r a s shown i n Photo. 2. The e l o n g a t i o n was reached up t o 60% a t t h e f r a c t u r e . I n t h i s c a s e , t h e m a r t e n s i t e s
i n ( b ) was l a r g e r t h a n t h a t i n ( a ) of s i n g l e c r y s t a l i s t h o u g h t t o be o r i g i n a t e d by t h e homogeneity i n d e f o r m a t i o n a s s o c i a t e d w i t h t h e f o r m a t i o n of a; m a r t e n s i t e . Con- t r a r y t o t h i s , f o r a t y p e B specimen of b i c r y s t a l , i t i s supposed t h a t t h e g r a i n boundary might o p e r a t e s o a s t o i n c r e a s e inhomogeneous d e f o r m a t i o n s i n t h e specimen, because i t produces a s p e c i a l l y deformed c r o s s - s e c t i o n a l r e g i o n i n t h e specimen. I n f a c t , t h e f r a c t u r e s t r a i n s i n t y p e B specimens were always s m a l l e r t h a n t h o s e i n s i n g l e c r y s t a l s .
One s e e s a q u i t e d i f f e r e n t s t r e s s - s t r a i n c u r v e f o r a t y p e A b i c r y s t a l specimen c o n t a i n i n g 1 5 % A 1 a s i n ( d ) . I n t h i s a l l o y , o n l y t h e
~ ~ - f @ ;
t r a n s f o r m a t i o n t o o k p l a c e and no remarkable s l i p d e f o r m a t i o n was i n t r o d u c e d . The f r a c t u r e o c c u r r e d a t a n e l o n g a t i o n of o n l y 1 0 % and t h e f r a c t u r e s u r f a c e showed a p a t t e r n of b r i t t l e f r a c t u r e . A s e p a r a t e measurement [ 8 ] showed t h a t t h e c r i t i c a l r e s o l v e d s h e a r s t r e s s (CRSS) f o r t h e f3i-tai t r a n s f o r m a t i o n , Q , was a l m o s t independent o f t e m p e r a t u r e b u t s t r o n g l y depended on t h e composition i n a l l o y s . An example o f measured T& f o rh
V
"''t b I/) V) a# 100 (a-l 10
- / 2 0 30 40
50 60 Strain
F i g . 3 S t r e s s - s t r a i n c u r v e s w i t h d i f f e r e n t f r a c t u r e s t r a i n . ( a ) S i n g l e c r y s t a l o f Cu-31.6at%Zn-4.2at%AL a l l o y . (b) B i c r y s t a l o f Cu-31.6at%Zn-4.2at%Al a l l o y . (c) p o l y c r y s t a l of Cu-31.6at%Zn-4.2at%Al a l l o y . (d) B i c r y s t a l of Cu-16.7at%Zz-15.0at%Al a l l o y . ( e ) P o l y c r y s t a l o f Cu-16.7at%Zn-15.Oat%Al a l l o y .
JOURNAL DE PHYSIQUE
Fig. 4
V a r i a t i o n of c r i t i c a l r e s o l v e d s h e a r stress f o r t r a n s f o r m a t i o n i n two Cu-Zn-Al a l l o y s . T@ and TH a r e t h e CRSS f o r
B1-t@i
and @!+al t r a n s - f o r m a t i o n s , r e s p e c t i v e l y . ( a ) Cu- 19.5at%Zn-13.0at%Al a l l o y . (b) Cu- 31.8at%Zn-4Dat%Al a l l o y .Cu-31.8at%Zn-4.0at%Al ( e / a = 1 . 3 9 8 , Ms=263"K) and Cu-19.5at%Zn-13.Oat%Al a l l o y ( e / a = 1 . 4 5 5 , Ms=263'K) i s r e p r e s e n t e d i n F i g . 4 accompanying w i t h t h e v a l u e s o f T ~ CRSS , f o r
B1+@i,
a t d i f f e r e n t t e m p e r a t u r e s . The above d a t a on CRSS c l e a r l y s u p p o r t t h a t t h e o b s e r v e d f r a c t u r e i n F i g . 3 (d) c a n be a t t r i b u t e d t o t h e l a c k o f a i m a r t e n s i t e a t t h e boundary. F i g . 3 ( c ) and ( e ) a r e t h e s t r e s s - s t r a i n c u r v e s f o r p o l y c r y s t a l - l i n e specimens w i t h l o w and h i g h A l c o n t e n t s , r e s p e c t i v e l y . The f r a c t u r e s t r a i n i n( c ) was a p p a r e n t l y l a r g e r t h a n i n ( e ) a s e x p e c t e d .
It i s concluded i n t h e p r e s e n t s t u d y t h a t t h e b e h a v i o r of s t r e s s - i n d u c e d t r a n s - f o r m a t i o n i s g r e a t l y a f f e c t e d by t h e s t r a i n c o m p a t i b i l i t y a t t h e g r a i n boundary i n Cu-Zn-Al a l l o y s . Moreover, i t was found t h a t t h e f o r m a t i o n of a j m a r t e n s i t e p l a y e d an i m p o r t a n t r o l e t o a t t a i n t h e s t r a i n c o m p a t i b i l i t y and t o avoid t h e f r a c t u r e a t t h e boundary. Even though t h e c u t t i n g of
B i
m a r t e n s i t e s i s d i f f i c u l t t o o c c u r i n g e n e r a l , a p a i r o f s p e c i a l v a r i a n t c r y s t a l s of@;
can c r o s s e a c h o t h e r t o form a;m a r t e n s i t e a s r e p o r t e d p r e v i o u s l y [ 5 ] , t h e phenomenon b e i n g c l o s e l y r e l a t e d t o t h e appearance o f t h e r e v e r s i b l e s h a p e memory e f f e c t i n Cu-Zn-A1 a l l o y s [ 9 ] . It i s s t r o n g l y dependent on t h e v a l u e of T,! whether o r n o t t h e c r o s s i n g of t h e
B i
marten-s i t e c a n e a s i l y o c c u r . So t h a t , i n a l l o y s w i t h h i g h A 1 c o n t e n t s , o n l y one v a r i a n t of 5; m a r t e n s i t e c a n u s u a l l y b e formed a t t h e boundary. S i n c e p o s s i b l e s h e a r systems a r e l i m i t t e d t h e r e , b e c a u s e o f t h e c r y s t a l s t r u c t u r e o f 9R, t h e s t r e s s i s h a r d l y r e l i e s e d . On t h e o t h e r hand, i n a l l o y s w i t h low A l c o n t e n t s , n o t o n l y a p a i r of v a r i a n t 6; i n b o t h g r a i n s can b e induced b u t a l s o a; m a r t e n s i t e s a r e formed e a s i l y a t t h e boundary. Consequently, t h e number o f p o s s i b l e s h e a r s y s t e m s i s i n c r e a s e d by a d d i n g f o u r {111}<110>~, s l i p s y s t e m s of m a r t e n s i t e and t h e s t r a i n c o m p a t i b i l i t y can become a t t a i n e d more e a s i l y .
R e f e r e n c e s
[ I ] Dvorak(1.) and Hawbolt(E.B.)
,
M e t . Trans. (1975) 95.[ 2 ] Schroeder(T.A.)
,
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Met. Trans. ( 1 9 7 6 ) 535.[ 3 ] Wield(D.V.), and G i l l a m ( E . ) , Acta Met.
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(1977) 725.[ 4 ] Miyazaki(S .)
,
Otsuka(K.),
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(1981) 244.[ 5 ] S a t o ( H . ) , Takczawa(K.), S a t o ( S . ) , Proc. J o i n t u s / J a p a n Seminar, Troy, N.Y., U.S.A. (1979) 92.
[ 6 ] L i v i n g s t o n ( J . D . ) and Chalmers(B.), Acta Met.
2
(1957) 322.[ 7 ] H i r t h ( J . P . ) and L o t h e ( J . ) , Theory o f D i s l o c a t i o n s , McGraw-Hill I n c . (1968) 284.
[ 8 ] Sato(H.)
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Takezawa(K.) and S a t o ( S . ),
S c i . Rep. RITU, Suppl. 1 @ (1981) 8 5 - [ 9 ] Takezawa(K.) and S a t o ( S . ) , P r o c . I n t e r n . Conf. on M a r t e n s i t i c T r a n s f o r m a t i o n s ,ICOMAT-79 (1979) 655.
