Preparation And Thermal Expansion Propertise Of SiC_P/Al Composites By Vacuum Pressure Infiltration Precess

SiCp/Al composites have excellent properties with high thermal conductivity, low coefficient of thermal expansion (CTE), high modulus and low density, so the research is one of the hotspot in modern materials science.The fabrication of preforms is the key technology during the preparation of the excellent performance SiCp/Al composite.At present , the reports about the fabrication of the preforms are few. Comparing with general method, there are many advantages with selective laser sintering(SLS) such as no die in the process of fabrication and complex shape of the performs can be fabricated. In all of preparation processes of SiCp/Al composites, there are good conditions of the vacuum pressure infiltration in special vacuum and pressure, which can improve the interface coalescent of Al and SiC particles, the section structure of SiCp/Al composites is also compact. The problem of air hole and inclusions can be avoided by controlling melt process. It is an excellent process of preparing SiCp/Al composites on high volume fraction.Blend epoxy resin and NH4H2PO4 to bond SiC particles in selective laser sintering is putted forward in this paper. Epoxy resin will bond SiC particles mainly in laser sintering, disassemble in the second sintering at 700℃and leave air hole in preforms. NH4H2PO4 will bond SiC particles in the second sintering. Combining the effect of the parameters on the performance of preforms with the purpose to improve sinter velocity, the best laser sintering technologies can be got by orthogonal design, they are as follow, laser power 30W; scanning velocity 1500 mm/s; scanning space 0.1 mm; single layer thickness 0.2 mm. SiCp/Al composites can be fabricated by vacuum pressure infiltration. And the distribution of SiC particles is equality and the volume ratio of SiC...