The disintegration of liquid lead streams by nitrogen jets
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5. G. Moritz: Z. Metallk., 1969, vol. 60, p. 694. 6. D. Altenpotd, R. C. Fonnerod, and A. Steinegger:Z. Metallk., 1969, vol. 60, p. 576. 7. D. T. Hurd, R. L. lkrto, and J. P. Stoltenberg: Trans. Amer. Foundrymen's Soc., 1968, vol. 99, p. 511. 8. K. H. Chien, T. Z. Kattamis, and F. R. Mollard:Met. Trans., 1973, vol. 4, pp. 1069-76. 9. B. K. Park, G. Lutjering,and S. Weissmann:Z. Metallk., 1971, vol. 62, p. 721. 10. C. Laird and G. Thomas:Intern. J. Fracture Mech., 1967, vol. 3, p. 81. 11. C. Thomasand J. Nutting: J. Inst. Metals, 1959160, vol. 88, p. 81. 12. C. Thomas and J. Nutting: Tram. TMS-AIME, 1967, vol. 239, p. 1033. 13. A. J. McEvily,Jr., R. L. Snyder, and J. B. Clark: Trans. TMS-AIME, 1963, vol. 227, p. 452.
The Disintegration of Liquid Lead Streams by Nitrogen Jets J. B R U C E SEE, J O S E P H C. R U N K L E , A N D T H O M A S B. KING
Fig. 5--Photomicrograph (a) and scanning electron micrograph (b) showing slip band extrusions in a region void of precipitate, magnification about 400 times. A1-4.5 wt pct Cu alloy specimen solutionized for 6 h at 535~ water-quenched and aged for 1 h at 375~ and fatigued for 2 • 106 cycles at 15,000 psi.
a r e a s v o i d of p r e c i p i t a t i o n . Slip b a n d s a p p e a r e d to e n d a t t h e b o u n d a r y of t h e d e n u d e d z o n e . The s c a n n i n g e l e c t r o n m t c r o g r a p h of F i g . 5(b) s h o w s how g r o s s t o p o g r a p h i c a l c h a n g e s p r o d u c e d b y s l i p l e d to t h e d e v e l o p m e n t of e x t r u s i o n s on t h e s p e c i m e n s u r f a c e . It is b e l i e v e d t h a t c r a c k s i n i t i a t e d in t h e s e a r e a s a s a r e s u l t of l o c a l i z e d p l a s t i c s t r a i n c a u s e d b y the e x t r u s i o n s . O c c a s i o n a l l y s o m e c r a c k s w e r e s e e n to n u c l e a t e in b o t h s e t s of s p e c i m e n s at i n t e r d e n d r t t i c p o r o s i t y and at t h e s u r f a c e of s e c o n d a r y p h a s e (0-A12Cu) p a r t i c l e s , w h i c h w e r e not d i s s o l v e d d u r i n g t h e s o l u t i o n t r e a t m e n t . Crack propagation observed by optical microscopy w a s t r a n s g r a n u l a r . C r a c k s e x t e n d e d in l e n g t h and d e p t h joining other existing cracks. In r h e o c a s t a l l o y s t h e r e l a t i v e d e c r e a s e in f a t i g u e s t r e n g t h m a y b e o v e r l o o k e d b e c a u s e of the m a n y a d v a n t a g e s of t h i s p r o c e s s . It w a s found t h a t a f t e r a t r e a t m e n t of a b o u t 50 h a t 535~ t h e s t r u c t u r e w a s c o m p l e t e l y h o m o g e n i z e d and t h e f a t i g u e s t r e n g t h c o m p l e t e l y recovered. This work was jointly supported by Air Force Office of S c i e n t i f i c R e s e a r c h C o n t r a c t No. F 4 4 6 2 0 - 6 9 - C - 0 0 1 1 METALLURGICAL TRANSACTIONS
.tHIS i n v e s t i g a t i o n d e s c r i b e s t h e n a t u r e of t h e d i s i n t e g r a t i o n of a l e a d s t r e a m w h e n it is s t r u c k b y n i t r o g e n j e
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