Particle size influence on the strength relation for air sintered aluminum
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[2]. As can b e s e e n , p a r t i c l e s i z e p l a y s a v i t a l r o l e in the s t r e n g t h e n i n g . The f i n e s t p o w d e r p r o v i d e d t h e l a r g e s t s t r e n g t h s following the s i n t e r i n g t r e a t m e n t . 1.0
R. M. GERMAN R e c e n t l y , Hathi, Rein and Slipcevich x p r o p o s e d a r e l a t i o n b e t w e e n t e n s i l e s t r e n g t h and c o n s o l i d a t i o n p r e s s u r e for s i n t e r e d m e t a l p o w d e r c o m p a c t s . Data for a l u m i n u m and i r o n a g r e e d with the m o d e l . S u b s t a n t i a tion of such a r e l a t i o n is of s i g n i f i c a n t i m p o r t a n c e to the p o w d e r m e t a l l u r g i s t involved with p o r o u s s t r u c t u r e s . The p r e s e n t c o m m u n i c a t i o n a s s e s s e s the new s t r e n g t h r e l a t i o n with r e s p e c t to an a l t e r n a t i v e p r o c e s s i n g s c h e d u l e and v a r y i n g p a r t i c l e s i z e . It is shown that p a r t i c l e s i z e and p o w d e r c h e m i s t r y a r e i m p o r t a n t c o n s i d e r a t i o n s in such a r e l a t i o n , F o u r a l u m i n u m p o w d e r s w e r e s e l e c t e d for t h i s study, Powder g r a d e s H-3, H-15 and H-100, f r o m V a l l e y M e t a l l u r g i c a l , had a p p r o x i m a t e l y s p h e r i c a l s h a p e s and F i s h e r s u b s i e v e s i z e s of 5, 19 and 46 ~tm, r e s p e c t i v e l y . F r e e a l u m i n u m c o n t e n t s w e r e 98 to 99 pct, with no s i g nificant m e t a l l i c i m p u r i t i e s . The fourth p o w d e r was the i r r e g u l a r s h a p e d A l c o a 2 0 l A B blend of 4.4 p c t Cu0.8 p c t Si-0.6 p c t M g - b a l a n c e A1 with a F i s h e r s u b s i e v e of 31 ~ m . T r a n s v e r s e r u p t u r e b a r s p e c i m e n s 3.17 c m long, 1.27 c m wide and a p p r o x i m a t e l y 0.64 c m t h i c k w e r e u n i a x i a l l y p r e s s e d in a double a c t i n g s t e e l d i e in a c c o r d with A S T M - B 5 2 8 - 7 0 . D e n s i t i e s w e r e m e a s u r e d following both p r e s s i n g and s i n t e r i n g . $ i n t e r i n g was a c c o m p l i s h e d in a i r at 600~ with a u n i f o r m 2 h h e a t up, 1 h hold and f u r n a c e slow cool. T r a n s v e r s e r u p t u r e t e s t s w e r e p e r f o r m e d a s s p e c i f i e d in A S T M - B 3 7 8 - 6 5 . Initial t e s t s of up to e i g h t d u p l i c a t e s p e c i m e n s showed a s m a l l d a t a s c a t t e r , thus s u b s e q u e n t t e s t s r e l i e d on single specimens. The d e n s i t y d e p e n d e n c e on c o m p a c t i o n p r e s s u r e in both the p r e s s e d and s i n t e r e d conditions followed Eq. [1] o v e r the r a n g e s t u d i e d , logp=mlogP+C
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Fig. 1--FractionaI density dependence on compaction p r e s s u r e for four aluminum powders following a 600~
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