The influence of titanium additions on the fracture behavior of iron
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Material*
Tension 0.2 pet Offset Yield Strength, psi
Compression 0.2 pet Offset Yield Strength, psi
Reference
A) 88in. diam bar B) ~- in. diam bar C) 88in. diam bar D) 88in. diam bar E) s in. diam bar
45,000 55,600 62,000 72,000 82,000
65,000 54,000 60,000 93,500 76,000
Olsen and Ansell~ Work at Battelle-Columbus Work at Battelle-Columbus Work at Battelle-Columbus Work at Allied Chemical
*The difference in magnitude of the strength levels from material to material probably arises from the fact that somewhat different thermomechanical processing treatments were used for the various heats.
t h e t e n s i o n a n d c o m p r e s s i o n y i e l d i n g b e h a v i o r . It i s clear that additional research is necessary to deter-
m i n e t h e c a u s e of t h i s i r r e p r o d u c i b i l i t y . 1. R. J. Olsen and G. S. Ansalh Trans. ASM, 1969, voL 62, p. 711.
The Influence of Titanium
Table I. Materials
Additions on the Fracture Behavior of Iron H. J . R A C K RELLICK and McMahon ~ have recently indicated that titanium is not as effective as aluminum in preventing low e n e r g y i n t e r g r a n u l a r b r i t t l e n e s s i n i r o n . H o w e v e r , t h e i r e x a m i n a t i o n w a s l i m i t e d to r a t h e r low t i t a n i u m c o n c e n t r a t i o n s (0.12 w t p e t ) . J o l l y 2 h a s a l s o i n d i c a t e d that as the titanium concentration increases a minimum in the transition temperature, as measured by the Charpy impact energy, occurs. Unfortunately, no grain sizes were reported by the latter investigator, and since t h i s i s a n i m p o r t a n t f a c t o r i n e s t a b l i s h i n g t h e low t e m p e r a t u r e p r o p e r t i e s of i r o n , t h e e x a c t i n f l u e n c e of titanium in this regard is still in doubt. This work was u n d e r t a k e n to c l a r i f y t h e r o l e t i t a n i u m a d d i t i o n s p l a y i n t h e d e f o r m a t i o n a n d f r a c t u r e b e h a v i o r of f e r r o u s alloys, T h e c o m p o s i t i o n s of t h e a l l o y s e x a m i n e d a r e g i v e n i n T a b l e I , t o g e t h e r w i t h a r e c o r d of t h e i r t h e r m o m e c h a n i c a l h i s t o r y p r i o r to t e s t i n g . I t s h o u l d b e n o t e d t h a t a l l of t h e a l l o y s p o s s e s s e d t h e s a m e g r a i n s i z e ( - 0 . 1 5 0 m m ) . T e n s i l e t e s t i n g w a s c a r r i e d o u t on e l e c tropolished cylindrical specimens 0.125 in. diam by 0 . 7 5 i n . g a g e s e c t i o n a t a n o m i n a l s t r a i n r a t e of 1.67 • 10 -3 s e c -1 b e t w e e n 25~ a n d - 1 9 5 ~ 3 A t -195~ a l l t h e a l l o y s , w i t h t h e e x c e p t i o n of t h e F e - 3 . 1 6 T i a l l o y , d e f o r m e d b y a m i x t u r e of s l i p a n d twinning while no evidence for twinning, unassociated with the main fracture, was found in the latter alloy. T h e a m o u n t of t w i n n i n g s h a r p l y d e c r e a s e d w i t h i n creasing test temperature; at -120~ only the Fe-0.003C exhibited any twin deformation. No twin
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