• PDF / 1,406,848 Bytes
• 10 Pages / 612 x 792 pts (letter) Page_size
• 69 Downloads / 265 Views

DOWNLOAD

REPORT

---

c r i b e d e l s e w h e r e . 7 The twelve d i f f e r e n t c o m b i n a t i o n s of p r o c e s s i n g and heat t r e a t m e n t r e s u l t e d in four m i c r o s t r u c t u r a l c a t e g o r i e s . It was one o b j e c t i v e of this w o r k to d e t e r m i n e the extent of m e c h a n i c a l p r o p e r t y g r o u p i n g s i n the twelve d i f f e r e n t p r o c e s s i n g Y h e a t t r e a t m e n t c o n d i t i o n s and the r e l a t i o n s h i p of these g r o u p s to those in which m i c r o s t r u c t u r e s fell. E X P E R I M E N T A L PROCEDURE MateriaI A l l m a t e r i a l t e s t e d in this i n v e s t i g a t i o n was t a k e n f r o m a s i n g l e heat p r o v i d e d by T I M E T i n the f o r m of 90 m m d i a m b i l l e t s . The c h e m i c a l a n a l y s i s of this heat was p r o v i d e d by the p r o d u c e r of this alloy and is given in T a b l e I. T h e .~ t r a n s u s t e m p e r a t u r e for t h i s heat was d e t e r m i n e d 7 to be 1845°F (1007°C). P r o c e s s i n g and Heat T r e a t m e n t Twelve m i c r o s t r u c t u r e s were created through comb i n i n g hot die f o r g i n g in the a +/3 and/3 r e g i o n s followed by v a r i o u s cooling r a t e s f r o m the f o r g e p r e s s and then by c o m b i n a t i o n of a + ~ and ~ heat t r e a t m e n t s followed by a u n i f o r m a n n e a l i n g and s t a b i l i z a t i o n t r e a t m e n t (Table II). F i g . 1 o u t l i n e s the s c h e m e r e p o r t e d in g r e a t e r d e t a i l e l s e w h e r e . ~ S e l e c t i o n of t h e s e s t r u c t u r e s w e r e b a s e d on the r e p o r t e d s u p e r i o r c r e e p s t r e n g t h of the fully t r a n s f o r m e d m i c r o s t r u c t u r e 4 while the/3 w o r k e d plus long t i m e a + ~ heat t r e a t m e n t had b e e n r e p o r t e d to have a s u p e r i o r b a l a n c e of e l e v a t e d t e m p e r a t u r e p r o p e r t i e s .8 Microscopy

D. EYLON, formerly a National Research Council Associate, Air Force Materials Laboratory, is now with the Department of Materials Science and MetallurgicalEngineering, University of Cincinnati, Cincinnati, OH 45221. J. A. HALL, formerly with AFML, is now with Titanium Metals Corporation of America, Henderson, NV 89005. C. M. PIERCE is with the Air Force Materials Laboratory, WrightPatterson Air Force Base, OH 45433, and D. L. RUCKLE is with Pratt and Whitney Aircraft, East Hartford, CT. Manuscript submitted January 13, 1976. METALLURGICALTRANSACTIONS A

O p t i c a l m i c r o s c o p y was u s e d to c h a r a c t e r i z e the v a r i o u s m i c r o s t r u c t u r e s a f t e r p r o c e s s i n g and heat t r e a t m e n t , as well as the r e l a t i o n s h i p b e t w e e n the s t r u c t u r e and the c r a c k path in f r a c t u r e t o u g h n e s s and F C P s p e c i m e n s f l S p e c i m e n s w e r e p r e p a r e d by c o n v e n t i o n a l m e c h a n i c a l p o l i s h i n g t e c h n i q u e s and etched with K r o l l s r e a g e n t . F o r d