Microstructure and properties of SiCp/Al electronic packaging shell produced by liquid-solid separation

The electronic packaging shell of high silicon carbide (54%SiC, volume fraction) aluminum-based composites was produced by liquid-solid separation technique. The characteristics of distribution and morphology of SiC as well as the shell's fracture surface were examined by optical microscopy and scanning electron microscopy, and the thermo-physical and mechanical properties of the shell were also tested. The results show that Al matrix has a net-like structure while SiC is uniformly distributed in the Al matrix. The SiCp/Al composites have a low density of 2.93 g/cm(3), and its relative density is 98.7%. Thermal conductivity of the composites is 175 W/(m.K), coefficient of thermal expansion (CTE) is 10.3x10(-6) K-1 (25-400 degrees C), compressive strength is 496 MPa, bending strength is 404.5 MPa, and the main fracture mode is brittle fracture of SiC particles accompanied by ductile fracture of Al matrix. Its thermal conductivity is higher than that of Si/Al alloy, and its CTE matches with that of the chip material.