A temperature correlation of the low-cycle fatigue data for 304 stainless steel
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3.0 Bu - Au ALLOYS 1550°C O EXPERIMENTAL P O I N T S AT 1 5 5 0 % • D E R I V E D TROM EQUATION IN TABLE I I
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4 . JANAF Thermochemical tables, Clearinghouse for Federal Scientific and Technical Information, Washington, D.C., 1965. 5. E. S. Tankins: Unpublished Data, Naval Air Development Center, Warminster, Pa. 18974. 6 . E. S. Tankins: Can.Met. Quart., 1970, vol. 9 , pp. 353-57. 7 . M. M.A. EI-Naggar andN. A.D. Parlee: Met. Trans., 1970, vol. 1 , pp. 909-11. 8 . R. J. Fruehan: Met. Trans., 1970, vol. 1, pp. 3403-10.
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REFERENCE 6
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A Temperature Correlation of the Low-Cycle Fatigue Data for 304 Stainless Steel
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Fig. 2--Variation of Logyo_with composition f o r the C u - A u s y s t e m , at 1550°C.
f o r c e s m u s t in s o m e w a y a c c o u n t f o r t h e l o w e r i n g o f t h e c h e m i c a l p o t e n t i a l o f o x y g e n in s o l u t i o n . E x t r e m e c a r e m u s t be e x e r c i s e d w i t h c o p p e r a n d c o p p e r a l l o y s i n o r d e r not t o l o s e o x y g e n o n s o l i d i f i c a t i o n . T h e a u t h o r has experienced this difficulty with p u r e c o p p e r , C u - A u , C u - A g , C u - P t , C u - N i , a n d CuC o a l l o y s . S p e c i m e n s that w e r e r a p i d l y q u e n c h e d into a n a r g o n a t m o s p h e r e r e s u l t e d i n a 10 t o 20 p e t l o w e r o x y g e n c o n t e n t t h a n s p e c i m e n s q u e n c h e d in t h e s a m e P H 2 0 / P H2 r a t i o a s t h e e q u i l i b r i u m r u n . T h e r e i s no e x p l a n a t i o n f o r t h i s loss o f o x y g e n in c o p p e r at t h e present t i m e . From consideration of the m a x i m u m uncertainties i n t h e t e m p e r a t u r e , P H 2 0 / p H2 r a t i o a n d o x y g e n a n a l y s i s , t h e a u t h o rx e a r l i e r s u g g e s t e d a m a x i m u m e r r o r o f a b o u t + 5 p e t o f t h e d e r i v e d v a l u e o f K~. T h e e r r o r f o r t h e C u - A u s y s t e m is c o n s i s t e n t w i t h t h i s v i e w bel o w t h e 67 p e t A u c o m p o s i t i o n r a n g e . A b o v e t h e 67 p c t A u r a n g e t h e e r r o r g o e s up r a p i d l y w i t h i n c r e a s i n g A u c o n t e n t s , b e c a u s e o f the u n c e r t a i n t i e s i n t h e h i g h PH.O/PH° and low oxygen v a l u e s w h i c h are c h a r a c t e r i s t l c in t h i s r a n g e . U n p u b l i s h e d e q u i l i b r i u m d a t as f o r p u r e g o l d i n d i c a t e s that i t s e q u i l i b r i u m c o n s t a n t a t 1550°C i s o n t h e o r d e r o f 10 s . H o w e v e r , t h e e x p e r i m e n t a l d i f f i c u l t i e s w i t h our p r e s e n t e q u i p m e n t m a k e it i m p o s s i b l e to get a m o r e e x a c t v a l u e . T h e e x p e r i m e n t a l r u n s a t 1550°C b u b b l i n g pure oxygen and oxygen m i x e d with controlled a m o u n t s of a r g o n r e s u l t e d i n v a l u e s o f 1 t o 2 p
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