Microstructure and properties of SiC_p/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/（·K）, coefficient of thermal expansion （CTE） is 10.3×10^-6 K-1 （25-400 ℃）, 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.

Semisolid forging electronic packaging shell with silicon carbon-reinforced copper composites

To fabricate electronic packaging shell of coppermatrix composite with characteristics of high ther mal conductivity and low thermal expansion coefficient, semisolid forming technology, and powder metallurgy was combined. Conventional mechanical mixing of Cu and SiC could have insufficient wettability, and a new method of semisolid processing was introduced for billets preparation. The SiC/Cu composites were first prepared by PM, and then, semisolid reheating was performed for the successive semisolid forging. Composite billets with SiC 35 % vol ume fraction were compacted and sintered pressurelessly, microstructure analysis showed that the composites pre pared by PM had high density, and the combination between SiC particles and Cualloy was good. Semisolid reheating was the crucial factor in determining the micro structure and thixotropic property of the billet. An opti mised reheating strategy was proposed： temperature 1,025 ℃and holding time 5 min.

Numerical simulation on thixoforging of electronic packaging shell with SiC_p/A356 composites

Based on the research of modem electronic packaging materials, thixo-forming technology was used to fabricate electronic packaging shell. The process of thixo-extrusion with SiCp/A356 composites was simulated by the finite element software DEFORM-3D, then the flow velocity field, equivalent strain field and temperature field were analyzed. The electronic packaging shell was manufactured by extrusion according to the results from numerical simulation. The results show that thixo-forming technology can be used in producing electronic package shell with SiCp/A356 composites, and high volume fraction of SiCp with homogeneous distribution can be achieved, being in agreement with the requirements of electronic packaging materials.