Determination of thermodynamic interaction parameters in solid V-Ti-Cr alloys using the mass spectrometer
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( T A v = 1800 K)
~2TiCr = 1.9 • 0.4 k c a l / g - a t o m ; 0.1 < N v < 0.4
(TAv = 1750 K)
f~VCr = 3.1 • 0.7 k c a l / g - a t o m ; 0.1 < NTi < 0.4
(TAv = 1850 K)
A t e m p e r a t u r e dependent f o r m was an a p p r o p r i a t e r e f i n e m e n t of the r e s u l t s f o r the T i - C r s y s t e m f r o m 1500 to 1840 K. That e x p r e s s i o n is f2= 28 (1
T 1840 ~ )
kcal/g-atom
O v e r a l l , e x p e r i m e n t a l r e s u l t s show i m p o r t a n t , but not c o m p l e t e , a g r e e m e n t with e s t i m a t e s f r o m p h a s e d i a g r a m s and t h e o r e t i c a l l y c a l c u l a t e d v a l u e s .
T H E R E i s p r e s e n t l y s u b s t a n t i a l i n t e r e s t in the t h e o r y and p r o p e r t i e s of t r a n s i t i o n m e t a l , b i n a r y a l l o y s ; but for p r a c t i c a l r e a s o n s it is t e r n a r y o r h i g h e r - o r d e r a l l o y s which a r e being developed. In o r d e r to u n d e r stand the m o r e complex f e a t u r e s of t h e s e a l l o y s , s y s t e m a t i c t h e r m o d y n a m i c p r o p e r t i e s m u s t be m e a s u r e d and c o r r e l a t e d . M a s s s p e c t r o m e t r i c t e c h n i q u e s have b e e n quite u s e f u l for this in s t u d i e s of b i n a r y alloy s y s t e m s , 1-6 and the method has b e e n extended to t e r n a r y s y s t e m s . 7,s The p u r p o s e of this study was to i n v e s t i g a t e the utility of t h e s e t e c h n i q u e s in m e a s u r i n g i n t e r a c t i o n coefficients of t e r n a r y alloy, solid s o l u t i o n s . The V - T i C r s y s t e m was chosen b e c a u s e of the p o s s i b l e a p p l i c a tion to B p h a s e t i t a n i u m alloy d e v e l o p m e n t , 9 and b e c a u s e the b i n a r y a l l o y s of V - T i , T i - C r , and V - C r have been p r e v i o u s l y i n v e s t i g a t e d and t h e i r t h e r m o d y n a m i c properties reported. '~ The u s e of the K n u d s e n effusion t e c h n i q u e , coupled with the m a s s s p e c t r o m e t e r has p r e v i o u s l y been a p p l i e d to s t u d i e s of b i n a r y a l l o y s p r i n c i p a l l y in the l i q EDMUND J. ROLINSKI, formerly Graduate Student, Department of Materials Science and MetallurgicalEngineering,University of Cincinnati, Cincinnati, Ohio, is now Materials Engineer, Air Force Materials Laboratory, WPAFB,Ohio. MICHAELHOCH, is Professor of Materials Science and Head Department of Materials Science and Metallurgical Engineering, University of Cincinnati. CHARLESJ. OBLINGER, is Research Assistant, Department of Materials Science and Metallurgical Engineering,University of Cincinnati. This paper is based on a portion of the thesis submitted by EDMUND J. ROLINSKI in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Materials Science, at the University of Cincinnati. Manuscript submitted November 1, 1971. METALLURGICALTRANSACTIONS
uid region w h e r e s e n s i t i v i t y and r e p r o d u c i b i l i t y of the v a p o r p r e
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