Van den Beukel_1976_Inhomogeneous plastic deformation in a Au-Cu alloy

This can be done as f o l l o w s as an example we s

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: o w s . As an example we s h a l l take the case ~ = 12~; and t = 10 min ( f i g . 1). The c o r r e s p o n d i n g s t r a i n o f the f i r s t band is 2.2~. Th a p r o p a g a t i o n time o f the f i r s t b and is found from ( 1 ) : t L = 0,44 min. Now from f i g . 1 by e x t r a p o l a t i o n the v a l u e o f A¢, is d e t e r m i n e d c o r r e s p o n d i n g to t = 0,44 min and c = 12 + 2.2 = 14.2~;. The resul~E is & c , = 1.5%, t o be compared wi~h the v a l u e o b s e r v e d f o r the second band: AEi. = 1.4%. ~n the same way the l[Jders s t r a i n o f an e v e n t u a l t h i r d band can be d e t e r m i n e d and compared w i t h the o b s e r v e d one. In a l l cases which a l l o w e d a c omparison o f t h i s k i n d a r e a s o n a b l e agreement was o b t a i n e d . 2 . 3 . The PL e f f e c t . I f a f t e r a g i n g the t e n s i l e t e s t is continued a t a low enough s t r a i n r a t e , t h e r e g i o n is e n t e r e d where in an u n i n t e r r u p t e d t e s t the PL e f f e c t o c c u r s . Again the l[Jders s t r a i n can be d e t e r m i n e d from f i g . 1 as d e s c r i b e d sub 2 . 2 . a nd compared w i t h o b s e r v e d v a l u e s . Again the agreement was r e a s o n a b l e . I t is c o n c l u d e d t h a t a t constant t e m p e r a t u r e the l~Jders s t r a i n is the same f u n c t i o n o f p r e s t r a i n and a g i n g time f o r a l l t h r e e types o f inhomogeneous d e f o r m a t i o n . F i n a l l y the c r i t i c a l s t r a i n E f o r the s t a r t o f the PL e f f e c t was d e t e r m i n e d as a f u n c t i o n o f the imposed s t r a i c r a t e a t room t e m p e r a t u r e . The r e s u l t was = 1~ = 0 ,21 i n accordance w i t h (2) . Ec 2.4 the r e s u l t of Wijler [2]. 3 . DISCUSSION I t w i l l be shown t h a t most o f the r e s u l t s can be u n d e r s t o o d by i n t r o d u c i n g the following assumption: I qhomo~eneous d e f o r m a t i o n occurs when the i n c r e a s e o f the s o l u t e c o n c e n t r a t i o n a t t he d i s ] o c a t i o n s exceeds a c r i t i c a l ' v a l u e . This assumpt'ion was used by...
View Full Document

Ask a homework question - tutors are online