Diffusion of titanium in copper
- PDF / 388,312 Bytes
- 5 Pages / 612 x 792 pts (letter) Page_size
- 25 Downloads / 207 Views
• 10 -4 exp [ - ( 1 9 6 • 2) kJ
mol-i/RT] m 2 / s .
The d i f f e r e n c e in the a c t i v a t i o n e n e r g i e s f o r the i m p u r i t y d i f f u s i o n of the 3 d - t r a n s i t i o n m e t a l s and s e l f - d i f f u s i o n in c o p p e r h a s b e e n c a l c u l a t e d by a p p l y i n g L e C l a i r e ' s m o d e l with the o s c i l l a t i n g p o t e n t i a l of the i m p u r i t y a t o m in c o p p e r . The c a l c u l a t e d v a l u e s a g r e e w e l l with the e x p e r i m e n t a l v a l u e s including the p r e s e n t one.
T H E O R E T I C A L c a l c u l a t i o n on the a c t i v a t i o n e n e r g y f o r the diffusion of p o l y v a l e n t m e t a l s in c o p p e r h a s b e e n s u c c e s s f u l l y m a d e by L e C l a i r e , ~ h o w e v e r , h i s t r e a t m e n t b a s e d on the m o d i f i e d s c r e e n e d C o u l o m b p o t e n t i a l 2 of i m p u r i t y in c o p p e r has f a i l e d in the c a s e of i m p u r i t i e s , such a s F e , Co and Ni. At that t i m e , e x p e r i m e n t a l diffusion d a t a of the o t h e r 3dt r a n s i t i o n m e t a l s in c o p p e r w e r e not a v a i l a b l e . R e cently, the p r e s e n t a u t h o r s have c a r r i e d out the e x p e r i m e n t a l study of the diffusion of V 4s, C r 51 and Mn s4 in copper.3 T r a c e r diffusion of t i t a n i u m in copp e r has n e v e r been s t u d i e d . H o w e v e r , d e m a n d f o r d i f f u s i o n d a t a of t h i s a l l o y s y s t e m is going up, b e c a u s e c o p p e r - t i t a n i u m a l l o y i s one of the i m p o r t a n t h e a t - r e s i s t i n g c o p p e r a l l o y s , and the k i n e t i c s of p r e c i p i t a t i o n , m o d u l a t e d s t r u c t u r e f o r m a t i o n and i n t e r n a l o x i d a t i o n in c o p p e r - r i c h C u - T i a l l o y s have b e e n s t u d i e d b y s e v e r a l a u t h o r s . T h e only a v a i l a b l e diffusion d a t a of C u - T i s y s t e m a r e o b t a i n e d by R e x e r , 4 who had e s t i m a t e d the i n t r i n s i c diffusion c o e f f i c i e n t s of t i t a n i u m in C u - l . 1 and 4.1 at. pct T i a l l o y s at only two t e m p e r a t u r e s , 1073 and 1173 K, b a s e d on the b o r o n i z i n g e x p e r i m e n t of the a l l o y s . In the p r e s e n t work, which is one of the s e r i e s of i m p u r i t y diffusion s t u d i e s in c o p p e r , the i n t e r d i f f u s i o n c o e f f i c i e n t in v e r y d i l u t e C u - T i a l l o y s has b e e n d e t e r m i n e d in the t e m p e r a t u r e r a n g e b e t w e e n 973 and 1283 K, and the i m p u r i t y diffusion c o e f f i c i e n t of t i t a n i u m in c o p p e r is d e t e r m i n e d by a p p l y i n g D a r k e n ' s r e l a t i o n s on the diffusion d a t a . It is a l s o a t t e m p t e d to c a l c u l a t e the a c t i v a t i o n e n e r g y f o r the diffusion of 3 d - t r a n s i t i o n m e t a l s in c o p p e r by a p p l y i n g L e C l a i r e ' s t r e a t m e n t b a s e d
Data Loading...
