Detection of plastic microstrain in aluminum by acoustic emission
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Composition, Wt Pct Rh
III. Cont'd
PH2/PH2
%O
PHz o/PH2 [?~ O]
Fe-Pd-Ni Wt Pct Pd-Ni 1Pd-lNi 2.5Pd-2.5Ni 2.5Pd-2.5Ni 4Pd-4Ni 4Pd-4Ni 4Pd-4Ni 5.5Pd-5.SNi 7Pd-7Ni 7.5Pd-7.5Ni 9Pd-9Ni 9Pd-9Ni
0.191 0.200 0.0194 0.118 0.176 O.194 O.114 0.194 0.117 0.116 0.176
0.0464 0.0297 0.0476 0.0272 0.0433 0.0487 0.0281 0.0479 0.0288 0.0284 0.0433
4.07 4.04 4.07 4.06 4.06 3.99 4.06 4.06 4.06 4.07 4.06
9. E. S. Tankins: Unpublished data, NAVAIRDEVCEN,Johnsville, 1969. 10. E. S. Tankins and W. A. Sipes: Trans. ASM, 1966, vol. 59, pp. 535-43. 11. M. Hansen and K. Anderko: Constitution of Binary Alloys, McGraw-HillBook Co., New York, 1958. 12. JANAP Thermochemical tables. The Dow Chemical Company, Midland, Mich., 1961. 13. C. Wagner: Thermodynamics of Alloys, Addison-WesleyPress, Cambridge, Mass., 1952.
Detection of Plastic Microstrain in Aluminum by Acoustic Emission
Fe-Pd-Ni-Pt
A. B. L. AGARWAL, J. R. FREDERICK, AND D. K. FELBECK
Wt Pct Pd-Ni-Pt 1Pd-lNi-lPt 2Pd-2Ni-2Pt 3Pd-3Ni-3Pt 3Pd-3Ni-3Pt 4Pd-4Ni-4Pt 4Pd-4Ni-4Pt 4Pd-4Ni-4Pt 4.95Pd-4.95Ni-4.95Pt 5Pd-5Ni-5Pt 5Pd-5Ni-5Pt 5Pd-5Ni-5Pt 6Pd-6Ni-6Pt
0.191 0.089 0.0176 0.137 0.191 0.176 0.136 0.194 0.129 0.123 0.089 0.089
0.0460 0.0212 0.0413 0.0324 0.0450 0.0403 0.0314 0.0432 0.0295 0.0281 0.0205 0.0200
4.15 4.20 4.26 4.24 4.24 4.37 4.33 4.46 4.37 4.38 4.38 4.45
O.g06
0.65C
. ~ ~ ~ ~..
~-~~ ~ 0.60~
o
~
- ~
8 o
- 0./0
o-o
i
O - - - o.oo~_"
Fe-glll C ALLOYS-1550~ "~
~A
0.550
Fe -N; -0"~0- Fe-Pd-Ni ........ Fe-Pt -Pt --0.10
r -0.20
0.5(X 95
90 85 Wt. Pet.IRON J
Fig. 3--The v a r i a t i o n of the e q u i l i b r i u m c o n s t a n t K = P H 2 0 / P H [%0] and the a c t i v i t y c o e f f i c i e n t of oxygen at 1550~ f o r t h e - F e - P d , F e - P d - N i , and the F e - P d - N i - P t systems.
P I E Z O E L E C T R I C c r y s t a l s can d e t e c t v e r y l o w - i n t e n s i t y s t r a i n t r a n s i e n t s in s o l i d s , if the signal is s u f f i c i e n t l y a m p l i f i e d and e x t r a n e o u s n o i s e s a r e r e duced to a t o l e r a b l e l e v e l . T h i s m e t h o d of d e t e c t i n g a c o u s t i c e m i s s i o n s p r o v i d e s a unique m e a n s f o r s t u d y ing the b e h a v i o r of s o l i d s u n d er load. F r o m such study one m a y e x p e c t to obtain s o m e b e t t e r u n d e r standing of the m e c h a n i s m s that g o v e r n d e f o r m a t i o n processes. S t r e s s - i n d u c e d low l e v e l a c o u s t i c e m i s s i o n o r i g i n a t ing f r o m d i s l o c a t i o n m o t i o n in m e t a l s is dependent on t h e i r m i c r o s t r u c t u r e , as m i g h t be e x p e c t e d . Two r e s u l t s f r o m the p r e s e n t study that b e a r this out a r e as f o l l o w s : 1) s t r a i n - h a r d e n i n g r e d u c e d the e m i s s i o n of 99.99 pct A1 in a t e n s i l e t e s t f r o m an a c o u s t i c b u r s t count (above the n o i se t h r e s h o l d ) of 24,000 f o r an a nn e a l e d s p e c i m e n s t r e s s e d to 4.0 k s i to z e r o f o r the s e c o n
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