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m i n u m in both s i n g l e - p h a s e (3") and t w o - p h a s e (y + y ' ) a l l o y s could be q u a n t i t a t i v e l y d e t e r m i n e d and the e f f e c t of t i t a n i u m , p r e s e n t p r i n c i p a l l y in the 3" phase, could be i n f e r r e d . PROCEDURES Alloy C o m p o s i t i o n s The c o m p o s i t i o n s of both the Solid Solution and G a m m a P r i m e Alloys a r e p r e s e n t e d in T a b l e L The Solid Solution Alloys w e r e d e s i g n e d to s i m u l a t e the a l l o y c o m p o s i t i o n of the n i c k e l - r i c h s o l i d s o l u t i o n in c o m m e r c i a l s u p e r a l l o y s a f t e r p r e c i p i t a t i o n of s e c o n d p h a s e s such as 3", c a r b i d e s , and b o r i d e s . T h e s e a l l o y s w e r e p r e p a r e d by K i r b y s in a p r e v i o u s study. T he G a m m a P r i m e Alloys w e r e d e s i g n e d to s i m u l a t e c o m m e r c i a l s u p e r a l l o y c o m p o s i t i o n s , but to avoid the p r e s e n c e of c a r b i d e s and t h e i r i n t e r a c t i o n s with the V and 3" p h a s e s . T h e s e a l l o y s had p r e v i o u s l y b e e n s t udi e d

Table I. Composition of Experimental Alloys

Composition,Wt Pet Alloy A B C

Ni 32.10 31.05 30.04

1

Balance

2 3 4 5 6 7 8 9 10

Balance Balance Balance Balance Balance Balance Balance Balance Balance

Co

Cr

Mo

AI

Solid SolutionAlloys* 33.12 34.78 31.31 34.14 3.48 29.67 33.77 6.48

-

GammaPrime Alloyst 14.22 12.88 8.61 t 4.29 13.93 2.05 13.41 5.09 12.90 8.14 13.53 12.56 7.70 13.94 12.70 7.96

3.14 3.15 4.37 4.32 4.32 4.32 5.80 5.87 1.05 t.02

Ti

3.49 3.40

"0.013 to 0.016 pct C. tO.O04 to 0.011 pct C, 0.010 to 0.015 pct B, 0.02 pct Si, 0.07 pct Fe. VOLUME 6A, MARCH 1975-477

b y Loomis e t a l . 1 F o u r a l u m i n u m plus t i t a n i u m l e v e l s (3 pct Al, 489 pct Al, 6 pct Al, and 1 pct Al + 389 pct Ti n o m i n a l wt pct) were i n v e s t i g a t e d with m o l y b d e n u m l e v e l s f r o m 0 to 8 n o m i n a l wt pct in each of the four Al(Ti) s e r i e s . A c o n s t a n t n i c k e l - t o - c h r o m i u m r a t i o (5.8:1 on a weight b a s i s ) was m a i n t a i n e d , producing c h r o m i u m contents that d e c r e a s e d f r o m 14.29 to 12.56 wt pct as m o l y b d e n u m , a l u m i n u m , and t i t a n i u m w e r e added. Processing All alloys were v a c u u m induction m e l t e d in a l u m i n a c r u c i b l e s e m p l o y i n g the s p l i t - h e a t technique to p r o duce each of the t h r e e or four m o l y b d e n u m l e v e l s in the Solid Solution Alloys or in each of the Al(Ti) l e v e l s of the G a m m a P r i m e Alloys. All alloys were poured u n d e r a p a r t i a l p r e s s u r e of a r g o n into c y l i n d r i c a l molds 51 or 64 m m in d i a m . The Solid Solution Alloys w e r e h o m o g e n i z e d at 1260~ for 24 h in h y d r o g e n and a i r - c o o l e d . The G a m m a P r i m e Alloys were h o m o g e n i z e d and r o l l e d at 1230~ to effect a r e d u c t i o n of a r e a of a p p r