Hiroyuki Toda1, Naoya Inoue2,Ryoko Shinmura2 and Toshiro Kobayashi2
1Development Department II, Suzuki Motor Corp., Hamamatsu
Recently, the existence of PFZ layers in the vicinity of the reinforcement with a width of several ten nm have been reported in the aluminum alloy matrix composite. Solute atom segregation due to the non-equilibrium mechanisms has been observed simultaneously in this region.
Elastic-plastic finite element analyses have been performed to evaluate the effects of these locally-inhomogeneous matrix on the tensile mechanical properties of a 6061Al alloy matrix composite reinforced with aligned 22 vol%SiC whiskers. The reinforcement is assumed to be surrounded by the PFZ layers of 0, 44 and 88 nm widths in which the mechanical properties of the matrix are substituted by those of the Al-6%Mg alloy without precipitation.
The initial strain hardening rate decreases with increasing PFZ width, while the Young's modulus is almost independent of PFZ width. These results are primarily attributed to the plastic deformation near the corner of the reinforcement due to the considerably low elastic limit in the PFZ layer. The numerical results also provide a mechanistic rationale for experimentally-observed efficiency of the microstructural control in which the PFZ layer have been successfully vanished utilizing the gradient of the solute atom concentration near the interface.
(Received April 10, 1995)
metal matrix composite, precipitate free zone, segregation, finite element method, elastic-plastic analysis, whisker, aluminum alloy
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