Effect of rhenium alloying on lattice dilation of the Group VI-A refractory metals
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3.17rlrl ~ ~::~:~ReSLOPE
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3'15 I
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3.131
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I
M. G A R F I N K L E
IN v i e w of the
a n o m a l o u s e f f e c t s of l a r g e r h e n i u m additions on the r o o m t e m p e r a t u r e d u c t i l i t y of the Group V I - A e l e m e n t s , c h r o m i u m , m o l y d b e n u m , and t un g s t en , it is of i n t e r e s t to c o n s i d e r w h e t h e r or not unusual l a t t i c e d i l a t io n s m a y be p r e s e n t that m i g h t c o n t r i b u t e to this effect. The l a t t i c e p a r a m e t e r s of v a r i o u s W - R e and C r - R e b c c s o l i d solution a l l o y s w e r e m e a s u r e d using the D e b y e - S c h e r r e r method. The s t a r t i n g m a t e r i a l s , which a n a l y z e d to b e t t e r than 99.98 wt pct pure with l e s s than 20 ppm i n t e r s t i t i a l content, w e r e double a r c m e l t e d into 3000-g W - R e ingots or into 60-g C r - R e buttons. The W - R e a l l o y s w e r e e x t r u d e d into b a r s t o c k while the C r - R e buttons w e r e r o l l e d into s h e e t . C h e m i c a l a n a l y s e s w e r e run to d e t e r m i n e the a c t u a l r h e n i u m content, Table I. The a l l o y s w e r e filed to obtain p o w d e r s p e c i m e n s (-60 m e s h ) . A f t e r the r e m o v a l of any i r o n p a r t i c l e s , the p o w d e r s w e r e a n n e a l e d f o r 1 hr at 10 -s t o r r at a t e m p e r a t u r e of 1500~ (2732~ f o r the W - R e a l l o y s and 1150~ (2100~ f o r the C r - R e a l l o y s . No ch an g es in the i n t e r s t i t i a l c o n t e n t s w e r e d e t e c t e d by this t r e a t me n t . The l a t t i c e s p a c i n g s w e r e d e t e r m i n e d using a D e b y e - S c h e r r e r c a m e r a with S t r a u m a n i s - t y p e loading. ~ Copper r a d i a t i o n f i l t e r e d by n i c k e l foil was e m p l o y e d in t h e s e d e t e r m i n a t i o n s . G r e a s e d s i l i c a g l a s s f i b e r s upon which the v a r i o u s p o w d e r s w e r e a p p l ie d y i e l d e d dilute s a m p l e s for e x a m i n a t i o n . The t e m p e r a t u r e d u r i n g the e x a m i n a t i o n s was held within 5~ yielding r e s u l t s well within • The h i g h e s t angle r e f l e c t i o n s (400) w e r e used in d e t e r m i n i n g the l a t t i c e p a r a m e t e r s . ~ T a b l e I l i s t s the m e a s u r e d p a r a m e t e r s for the v a r i o u s W - R e and C r - R e alloys examined. F i g . 1 i l l u s t r a t e s the W - R e and C r - R e l a t t i c e data of T ab l e I. The l i m i t s of s o l i d solution a r e quite ap p a r e n t in this f i g u r e , i n d i c a t e d by the i n t e r s e c t i o n of
2. 98 LATTICE PARAI~ETER, 2. 96 -
_ SLOPE- A(~'/As~
2. 94 2.92
J
/ 2. 90
-
Cr-Re SLOPE= 0.1)85
9,"
at. pct Re
W-Re A + 0.003
at. pct Re
3.3 4.4 5.0 8.6 15.4 20.2 22.0 25.3 28.7 30.4 33.3
3.162 3.161 3.161 3.158 3.153 3.149 3.148 3.145 3.143 3.143 3.143
4.7 8.8 11.7 15.0 20.4 21.7 26.7 30.7 34.1 37.8
Cr-Re A -+ 0.002
2.900 2.911 2.9
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