Recrystallization and texture development in dispersion-strengthened nickel-base superalloys
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a d v a n c e s in powder m e t a l l u r g y 1-4 have e n a b l e d the p r o d u c t i o n of oxide d i s p e r s i o n s t r e n g t h ened (ODS) s u p e r a l l o y s f r o m powders with u n i f o r m d i s p e r s i o n s of oxide p a r t i c l e s within m a t r i c e s of the d e s i r e d s u p e r a l l o y c o m p o s i t i o n s . Methods of powder consolidation have a l s o been shown to influence final p r o p e r t i e s , e.g.,temperature and e x t r u s i o n r a t i o have m a r k e d effects on p r o p e r t i e s of extruded m a t e r i a l , s In addition, t h e r e has been c o n s i d e r a b l e effort devoted to the r e s p o n s e of extruded m a t e r i a l to a n n e a l i n g treatments.S'6 While these s t u d i e s have focused upon c r e e p p r o p e r t i e s and m i c r o s t r u c t u r a l c h a r a c t e r i s t i c s , little data c o n c e r n i n g the effect of a n n e a l i n g on t e x t u r e have been r e p o r t e d . The c o n t r o l l e d d e v e l o p m e n t of s p e c i f i c t e x t u r e r e m a i n s a n i m p o r t a n t c o n s i d e r a t i o n if, for e x a m p l e , an ODS component is to have r e s i s t a n c e to high t e m p e r a t u r e t h e r m a l fatigue, for which e i t h e r a (100){001} or a (110){001} t e x t u r e is p r e f e r r e d . 7 The a r e a of t e x t u r e d e v e l o p m e n t in bulk s a m p l e s has focused upon s i l i c o n - i r o n s y s t e m s . % 9 The p r e s e n t study involves s u b j e c t i n g an extruded ODS s u p e r a l l o y (78 wt pct Ni, 16 wt pct Cr, 5 wt pct A1, 1 wt pct YzO3) to v a r i o u s c o m b i n a t i o n s of h o t - r o l l i n g and heat t r e a t m e n t s to d e t e r m i n e the effects upon the final t e x t u r e of the m a t e r i a l , and to seek and a t t e m p t to u n d e r s t a n d the conditions g o v e r n i n g the d e v e l o p m e n t of this final texture.
i t s e l f or to the s t e e l b a l l s in the a t t r i t o r . A flow diag r a m of the p r o c e s s is given in F i g . 1. Consolidation of the blended p o w d e r s was a c c o m p l i s h e d by canning, evacuation, and e x t r u s i o n . Ext r u s i o n p a r a m e t e r s included a t e m p e r a t u r e of 1120~ an e x t r u s i o n r a t i o of 12:1, and an e x t r u s i o n speed of 20.5 cm p e r rain. The a s - e x t r u d e d b a r m e a s u r e d 7 m m in t h i c k n e s s and 22 m m in width. The e x p e r i m e n t a l test m a t r i x ; shown in T a b l e I, involves s u b j e c t i n g a s - e x t r u d e d m a t e r i a l to 10 and 20 pct d e f o r m a t i o n s , r e s p e c t i v e l y , at 1010 and 1150~ and then applying v a r i o u s r e c r y s t a l l i z a t i o n t r e a t m e n t s . The a s - e x t r u d e d m a t e r i a l was hot worked by equalizing at the r o l l i n g t e m p e r a t u r e and t r a n s f e r r i n g to a s m a l l r o l l i n g m i l l . The r o l l i n g d i r e c t i o n was long the longitudinal faces of the s a m p l e s , i.e., p a r a l l e l to the e
