Preparation, microstructures and deformation behavior of SiCP/6066Al composites produced by PM route

Preparation, microstructures and deformation behavior of 12 vol.% SiC_P/6066Al composites fabricated by a powder metallurgy (PM) route have been systemically reported in this paper. The experimental results indicated that SiC particles were distributed homogeneously in the aluminum matrix, and that the constituents of the matrix were Al, needle-shaped β′-Mg₂Si phases and a small amount of dispersoids (Fe, Mn, Cu)₃Si₂Al₁₅ (BCC structure with lattice parameter a ≈ 12.8 Å). A well-bonded SiC/Al interface consisting of a thin and clean layer of polycrystalline structure of metal matrix with segregation of Mg element has been observed. The SiC particle cracking and the ductile-tearing of SiC/Al interfaces caused the rupture of the composites. The experimental data coincided well with the theoretical results predicted by an extended effective model assumption (EMA). The current study indicates that load transfer between the matrix and reinforcements, grain refinement of metal matrix, and dislocation strengthening are the main strengthening mechanisms of SiC_P/Al composites. The ductile-tearing of SiC_P/Al interfaces and the SiC particle cracking are the dominating failure modes and the deformation behavior of SiC_P/Al composites strongly depends on the properties of matrix alloy.