Producing basal textured Ti-6Al-4V sheet
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MANYi m p o r t a n t
p r o p e r t i e s of alpha and a l p h a - r i c h titanium alloys depend on the p r e s e n c e or lack of c r y s t a l l o g r a p h i c t e x t u r e . P e r h a p s the m o s t c o m m o n s t r o n g s h eet t e x t u r e in a l p h a - b e t a alloys is one with the b a s a l plane p o l e s c o n c e n t r a t e d n e a r the t r a n s v e r s e d i r e c t i o n . 1-3 Sheet with such a t e x t u r e is w e a k e r in the longitudinal d i r e c t i o n c o m p a r e d to the t r a n s v e r s e d i r e c t i o n with y ie ld s t r e n g t h d i f f e r e n c e s of up to 17• 106 Pa o r m o r e . 1 F o r b i a x i a l l y s t r e s s e d applications such as p r e s s u r e v e s s e l s , a t e x t u r e with the b a s a l plane p o l es n o r m a l to the plane of the s h eet would be v e r y d e s i r a b l e j-7 Such a b a s a l plane t e x t u r e would show t e x t u r e s t r e n g t h e n i n g and v e r y high biaxia[ s t r e n g t h s could be r e a l i z e d . Unfortunately, c o m m e r cial p r o c e s s i n g p r o c e d u r e s have not been d e v e l o p e d f o r b a s a l plane t e x t u r e although m o d e r a t e s i z e d s h e e t s have been p r o d u c e d on an e x p e r i m e n t a l basis.8 T h e r e is also a lack of i n f o r m a t i o n on the m e c h a n i s m s of t e x t u r e f o r m a t i o n during w a r m and hot r o l l i n g of a l p h a - b e t a t i t a n i u m alloys which would p e r m i t a priori s e l e c t i o n of p r o c e s s i n g conditions f o r producing b a s a l t e x t u r e d s h e e t . In this p r o g r a m , the influence of p r o c e s s i n g v a r i a b l e s on t e x t u r e d e v e l o p m e n t in T i 6A1-4V w e r e s t u d i ed and the n e c e s s a r y conditions for produci n g s t a n d a r d s h e e t with a b a s a l plane t e x t u r e were established.
PROCEDURES To eliminate any scaling problems between laboratory and mill practice, most of the processing was performed in production facilities. For the initial experiments, half of a standard ingot with the composition given in Table I was double upset and then forged at temperatures of 1366, 1255, and 1200 K to m a k e 89 m m thick by 406 m m wide by r a n d o m length sheet bar. These were cut into pieces 203 m m by 406 m m o r 406 m m by 406 m m for r o l l i n g at t e m p e r a t u r e s between 811 and 1080K. R o l li n g was p e r f o r m e d on a 1.5 m hand m i l l , r e h e a t i n g as n e c e s s a r y to m a i n tain the r o l l i n g t e m p e r a t u r e within about 28 K of the nominal value. The t e m p e r a t u r e of the r o l l s w e r e S. F. FREDERICK, formerly with McDonnell Douglas Corporation, Huntington Beach, California, is now Member of the Technical Staff, Aerospace Corporation, El Segundo, CA. G. A. LENNING is Acting Manager, Toronto Technical Laboratory, Timet Division, Titanium Metals Corporation of America, Toronto, Ohio. Manuscript submitted October 29, 1974. METALLURGICALTRANSACTIONS B
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