The diffusion of antimony in alpha iron
- PDF / 573,269 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 89 Downloads / 198 Views
PERIMENTAL
PROCEDURE
Diffusion s p e c i m e n s were p r e p a r e d of l a r g e - g r a i n e d p o l y c r y s t a l s of f e r r o v a c iron which had b e e n a n n e a l e d for a prolonged p e r i o d j u s t below the a - y t r a n s f o r m a tion t e m p e r a t u r e to develop f e r r i t e g r a i n diam of 0.5 G. A. BRUGGEMANis Metallurgist,Materials SciencesDivision, Army Materials and Mechanics Research Center, Watertown, Mass. 02172. J. A. ROBERTS, JR. was Graduate Student, Department of Materials Scienceand Engineering,University of California, Berkeley, Calif. 94720. Manuscript submitted August 6, 1974. METALLURGICALTRANSACTIONSA
to 1 m m . Single c r y s t a l s of f e r r o v a c were also obtained by the s t r a i n - a n n e a l method for use in the lower t e m p e r a t u r e m e a s u r e m e n t s . T h r e e dilute i r o n a n t i m o n y alloys c o n t a i n i n g 0.066, 0.192, and 0.386 wt pct a n t i m o n y and an i r o n - 0 . 5 wt pct m o l y b d e n u m a l l o y were also p r e p a r e d . T h e s e were hot forged and then given s i m i l a r a n n e a l i n g t r e a t m e n t s j u s t below the ~ - y t r a n s f o r m a t i o n t e m p e r a t u r e to develop g r a i n diam of 0.3 to 0.5 m m . For the a n t i m o n y diffusion m e a s u r e m e n t s , one face of d i s c - s h a p e d s p e c i m e n s was e l e c t r o p l a t e d with Sb124 f r o m a c i t r a t e plating bath. az Sufficient a n t i m o n y was deposited to give a counting r a t e well in e x c e s s of 10,000 cpm; this c o r r e s p o n d e d to a deposited l a y e r roughly 5000A in t h i c k n e s s . F o r the i r o n self diffusion m e a s u r e m e n t s , s p e c i m e n s w e r e e l e c t r o p l a t e d with F e - 5 9 f r o m a s a t u r a t e d a m m o n i u m oxalate s o l u tion to give counting r a t e s and deposit l a y e r t h i c k n e s s e s s i m i l a r to those in the a n t i m o n y s p e c i m e n s . P a i r s of identical s p e c i m e n s with n e a r l y equal a c t i v i t i e s were e n c a p s u l a t e d in quartz a m p u l e s u n d e r an a t m o s p h e r e of d r i e d h i g h - p u r i t y argon. The c a p s u l e s were placed in holes d r i l l e d in l a r g e n i c h r o m e blocks, placed in the a n n e a l i n g f u r n a c e , and a n n e a l e d for p e r i o d s of f r o m one day to two weeks. T e m p e r a t u r e c o n t r o l was • 1~ After a n n e a l i n g , the edges of all s p e c i m e n s were ground to e l i m i n a t e any effects due to s u r f a c e diffusion. P e n e t r a t i o n p r o f i l e s were d e t e r m i n e d b y the r e s i d ual a c t i v i t y method in which s u c c e s s i v e l a y e r s were r e m o v e d by grinding, with the a c t i v i t y due to only the high e n e r g y g a m m a r a y s of 513-124 or F e - 5 9 counted after each r e m o v a l . D i f f e r e n t i a l weighings p e r m i t t e d the t h i c k n e s s of each l a y e r to be c a l c u l a t e d ; this was t y p i c a l l y 8 to 10 m i c r o n s . Secti
Data Loading...
