Radiation-induced strengthening and embrittlement in aluminum
- PDF / 2,377,654 Bytes
- 9 Pages / 612 x 792 pts (letter) Page_size
- 80 Downloads / 180 Views
R A D I A T I O N h a r d e n i n g o r s t r e n g t h e n i n g in m e t a l s is caused by microstructurat defects introduced during the i r r a d i a t i o n . In a l u m i n u m and its a l l o y s i r r a d i a t e d at about 323 K t h e s e d e f e c t s a r e u s u a l l y not v i s i b l e in an e l e c t r o n m i c r o s c o p e f o r n e u t r o n f l u e n c e s l e s s than about i 0 ~ n e u t r o n / m 2, but t h e y f o r m r e s o l v a b l e d i s l o c a t i o n l o o p s a t h i g h e r f l u e n c e s J At f l u e n c e s beyond 1 • 10 m n e u t r o n / m 2 o t h e r s t r u c t u r a l i m p e r f e c t i o n s such a s v o i d s a-5 and p a r t i c l e s of t r a n s m u t a t i o n - p r o d u c e d s i l i c o n 6'7 e n t e r the p i c t u r e . N e u t r o n i c a l l y induced g a s e s , in the f o r m of m a n y s m a l l b u b b l e s , will a l s o c a u s e s t r e n g t h e n i n g . 8 I r r a d i a t i o n s t r e n g t h e n i n g of a l u m i n u m is u s u a l l y a c c o m p a n i e d b y s o m e l o s s of d u c t i l ity, a but n o r m a l l y the f r a c t u r e m o d e r e m a i n s one of t r a n s g r a n u l a r s h e a r i n g and t e a r i n g , although n e c k i n g m a y b e c o m e h i g h l y l o c a l i z e d . H o w e v e r , when m a n y g a s b u b b l e s a r e p r e s e n t a i n t e r g r a n u l a r f r a c t u r e o c c u r s at e l e v a t e d t e s t t e m p e r a t u r e s , and it b e c o m e s m o r e p r e v a l e n t with i n c r e a s i n g g a s content o r with i n c r e a s i n g t e s t t e m p e r a t u r e . The p r e s e n t p a p e r d e s c r i b e s the e f f e c t s of n e u t r o n f l u e n c e and t e s t t e m p e r a t u r e on the m e c h a n i c a l s t r e n g t h of c o m m e r c i a l p u r i t y a l u m i n u m and r e p o r t s a s e v e r e d u c t i l i t y l o s s a s s o c i a t e d with i n t e r g r a n ular fracture. M A T E R I A L AND TEST CONDITIONS
The material was II00 grade aluminum [99 pct Al, 1 pct (Fe + Si)] from an Oak Ridge Research Reactor c o r e component, a c h e m i c a l t a r g e t t r a y known a s the NF t r a y . This t r a y was o r i g i n a l l y in an a n n e a l e d c o n dition b e f o r e it e n t e r e d eight y e a r s of i n - r e a c t o r s e r v i c e . The n a t u r e of t h i s t r a y , i t s i r r a d i a t i o n h i s t o r y , and d e t a i l s of the s e c t i o n i n g p r o c e d u r e u s e d to obtain t e s t s p e c i m e n s f r o m it a r e a v a i l a b l e e l s e w h e r e . l ~ B r i e f l y , the t r a y was i r r a d i a t e d in c o n t a c t with f l o w K. FARRELL and R. T. KING are Research Staff Members, Oak Ridge National Laboratory, Oakridge, Tenn. 37830. Manuscript submitted October 2, 1972. METALLURGICAL TRANSACTIONS
ing w a t e r at 318 to 328 K, the f a s t (E > 0.1 MeV)* *The SI unit of energyis the joule but the readerwillprobablyfeelmore at home with a cut-offenergyof 0.1 MeVthan one of 16 fJ. f l u e n c e s r a n g e d f r o m 1 to 3 • 1 0 26 n e
Data Loading...
