On the mechanism of texture transition in FCC metals
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P o l y c r y s t a l l i n e c o p p e r s h e e t s having o r i e n t a t i o n s ( 1 1 2 ) [ ] ] 1 ] and (011)[2]1] w e r e r o l l e d s u c c e s s i v e l y at two t e m p e r a t u r e s . When r o l l e d at the liquid n i t r o g e n t e m p e r a t u r e , the (112)[1il] t e x t u r e d e c r e a s e d m a i n l y by m e c h a n i c a l twinning, and it a l s o e x t e n d e d i t s s p r e a d t o w a r d (111)[]]2]. The r e s o l v e d s h e a r s t r e s s on the s l i p s y s t e m s , which p r o d u c e l a t t i c e r o t a t i o n s f r o m (112)[i]1] to (111)[]]2], is s m a l l e r than that on the s y s t e m s giving r i s e to i n v e r s e r o t a t i o n s . The f o r m a t i o n of the m i n o r c o m p o n e n t having (111) p l a n e s p a r a l l e l to the r o l l i n g plane in the a l l o y type r o l l i n g t e x t u r e can be e x p l a i n e d on the b a s i s of h a r d e n i n g of the latent s l i p s y s t e m s . When r o l l e d at r o o m t e m p e r a t u r e , the (112)[]]1] o r i e n t a t i o n was g r a d u a l l y r o t a t e d t o w a r d (011)[2il], but the o r i e n t a t i o n s p r e a d a r o u n d (112)[1]1] h a s s c a r c e l y i n c r e a s e d , in the s h e e t with the (011)[2]1] o r i e n t a t i o n r o l l e d up to 92 pct at 100~ T h e s e r e s u l t s i n d i c a t e that c r o s s - s l i p d o e s not c o n t r i b u t e to the d i s p l a c e m e n t f r o m (011)[211] to (112)[1]1], but r e t a r d s the i n v e r s e r o t a t i o n s . In c o n s e q u e n c e , the p r i m e f a c t o r for t e x t u r e t r a n s i t i o n i s the e a s e of m e c h a n i c a l twinning, r a t h e r than that of c r o s s - s l i p . T H E r o l l i n g t e x t u r e of c o p p e r c h a n g e s g r a d u a l l y f r o m the p u r e - m e t a l type to the a l l o y type with d e c r e a s i n g t e m p e r a t u r e of d e f o r m a t i o n , 1 o r with i n c r e a s i n g a l l o y content. 2'3 Such t e x t u r e t r a n s i t i o n can be c o r r e l a t e d with a change in the s t a c k i n g fault f r e q u e n c y 1 o r the s t a c k i n g fault e n e r g y , s B a s e d on an a r g u m e n t r e l a t i n g the s t a c k i n g fault e n e r g y with the e a s e of c r o s s - s l i p , D i l l a m o r e and R o b e r t s 4 s u g g e s t e d that c r o s s - s l i p would change the {011}(211) o r i e n t a t i o n to the p u r e m e t a l type t e x t u r e , a n d e v e n t u a l l y to the {112}(111) orientation. A t h e o r e t i c a l a n a l y s i s s'6 of the s l i p r o t a t i o n s , howe v e r , i n d i c a t e s that the (112)[i11] o r i e n t a t i o n can be d e v e l o p e d by n o r m a l s l i p r o t a t i o n s for c r y s t a l s having [1]0] in the t r a n s v e r s e d i r e c t i o n , e.g., (001)-(111) in the r o l l i n g p l a n e , and [ 1 ] 0 ] - [ ] 1 2 ] in the r o l l i n g d i r e c tion. C r y s t a l s in the (112)[i11] o r i e n t a t i o n c a n , then, r o t a t e t o w a r d the s t a b l e end p o s i t i o n (0
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