Grain size dependency of beta-plutonium plasticity
- PDF / 1,231,280 Bytes
- 3 Pages / 612 x 792 pts (letter) Page_size
- 59 Downloads / 262 Views
JANUARY 1971
i a t e d w i t h t h e a - ~ fi t r a n s f o r m a t i o n . E l e v a t e d - t e m perature deformation metallographic and X - r a y m e t a l lographic methods w e r e therefore developed for f i - P u a n d u s e d t o o b t a i n r e l a t i v e g r a i n s i z e d a t a f o r ]3c~ a n d ~/. U n a l l o y e d plutonium w a s successfully polished w h i l e a t / 3 - p h a s e t e m p e r a t u r e s by i m m e r s i n g the s p e c i m e n s in a n i n e r t s i l i c o n e fluid, w h i c h m i n i m i z e d o x i d a t i o n a n d also s e r v e d a s t h e p o l i s h i n g lubricant a n d heat t r a n s f e r m e d i u m . T h e specimens w e r e cleaned u s i n g t e t r a c h l o r o e t h y l e n e . T h e f i n a l p o l i s h i n g was p e r f o r m e d in a n e v a c u a t e d g l o v e b o x , a n d t h e s p e c i m e n s w e r e e x a m i n e d a t 120°C w h i l e t h e y w e r e i m m e r s e d i n t h e s i l i c o n e f l u i d . T h e p o l i s h e d ~3 c o u l d not be e t c h e d s a t i s f a c t o r i l y ; t h e r e f o r e , t h e /3 g r a i n s i z e w a s d e t e r m i n e d by d e f o r m i n g the p o l i s h e d /3 s u r f a c e s i n c o m p r e s s i o n and observing the deformation m i c r o s t r u c t u r e w i t h o p t i c a l a n d e l e c t r o n m i c r o s c o p y . The s p e c i m e n s t o be e x a m i n e d w e r e p o l i s h e d m e t a l l o g r a p h i c a l l y i n t h e fi p h a s e a n d t r a n s f e r r e d t o a h o t - s t a g e d e f o r m a t i o n a p p a r a t u s w h e r e they w e r e c o m p r e s s e d approximately 5 pct with the s t r e s s applied p a r a l l e l to t h e p o l i s h e d s u r f a c e . The p o l i s h e d , d e f o r m e d s u r f a c e s w e r e e x a m i n e d o p t i c a l l y a t 120°C in t h e /3 p h a s e a n d then in t h e a p h a s e a t r o o m t e m p e r a t u r e f o r s l i p t r a c e s a n d distorted g r a i n boundaries.
(a)
(b) Fig. 1--Deformation s t r u c t u r e p r o d u c e d on polished/?a and fly s u r f a c e s by 5 pet deformation in compression. (a) [~a, m a g nification 565 t i m e s . (b) fl./, magnification 280 times. MI;I'A[ tLJR(;I('A| fRANSA("] IONS
(a)
(c)
(b)
(d)
Fig. 2--X-ray diffraction photographs of unalloyed plutonium t r a n s f o r m e d c~ ~ ~, fi ~ ~/, and y ~ fi at 3°C per min. F i l t e r e d molybdenum radiation. T h e d i f f u s e c e n t r a l reflections common t o a l l of the patterns a r e from the s a m p l e h o l d e r~and f u r n a c e a s s e m b l y . (a) a - 2 5 ° C ; (b) f i a - 150°C; (c)T-2200C; ( d ) / 3 7 - 120°C. By c o m p a r i n g a n u m b e r o f s p e c i m e n s o p t i c a l l y at ~ p h a s e t e m p e r a t u r e s a n d t h e n at r o o m t e m p e r a t u r e , t h e d e f o r m a t i o n m i c r o s t r u c t u r e w a s o b s e r v e d t o be s u p e r i m p o s e d o n t h e s u r f a c e d i s t o r t i o n s c a u s e d by t h e ~ a transformation volume change. Transformation d i s t o r t e d t h e g r a i n b o u n d a
Data Loading...
