Preparation And Properties Of SiCp/Al Composites Prepared By Powder Thixoforming With Direct-heating

High volume fraction of SiCp/Al composites compared with the traditional electronic packaging materials, excellent physical properties and mechanical properties, it can not only used widely in the aerospace, military, automobile manufacturing, but also meet the requirements of the packaging materials such as IGBT substrate, which has become a hotspot of composite materials. This paper adopts the method of powder thixoforming with direct-heating which combines powder metallurgy and powder thixoforming technology to produce IGBT substrate with the SiCp/Al composites. The preparation parameters, the volume fraction of SiC and granularity of SiC powder about the thermal physical properties and mechanical properties of composites are researched by analysing the microstructure, testing density, thermal physical properties and mechanical properties.This paper takes the IGBT substrate as the research background, The preparation process of high volume fraction of SiCp/Al composites for substrate mainly includes the pretreatment of SiC particles, blending, powder thixoforming. The best preparation process parameters were determined by orthogonal experiment firstly; Then the influence of process parameters (sintering temperature, pressure time, heat preservation time after withdrawal) on the microstructure and density of the composites was studied by single factor experiment; Finally, the coefficient of thermal expansion, the thermal conductivity and the bending strength are tested, the influences which include sintering temperature, pressure time, different volume fraction of SiC particles and SiC particle ratio on them are studied.The results show that the SiC particles of composites distribute uniformly, the microstructure is compact, the fracture mode of SiCp/Al composites is brittle fracture when the volume fraction of SiC particles is 60%, the sintering temperature is 600 ℃, pressure time is 4 min, heat preservation time after pressurization is 2 min. When the average particle size of SiC particles are 100μm and 5μm, the particle size ratio is 9.5:0.5, the sintering temperature is 600℃, pressure time is 4 min, heat preservation time after withdrawal is 2 min, the thermal physical properties and mechanics performance are better, the coefficient of thermal expansion of composites from room temperature to 250℃ is 5.7× 10-6 · ℃-1, the thermal conductivity is up to 165W·m-1·℃-1, the bending strength is 340MPa, and the thermal physical properties and mechanical properties of composites can meet the using demand of the IGBT substrate.