Microstructures and properties of 50%SiCp/Al composites fabricated by powder metallurgy

50%SiCp/6061Al (volume fraction) composites were fabricated using powder metallurgy technique via ball-milling and pressureless sintering. The effect of sintering temperature on microstructures and properties of the SiCp/Al composites with high SiCp volume fraction was especially stressed. The results show that ball milling is beneficial to the uniform composition distribution of the 50%SiCp/6061Al composites powder. With increasing the sintering temperature, the density and bending strength of the 50%SiCp/Al composites increase initially and then decrease. The SiCp/Al composite sintered at 710℃ has the optimal properties, i.e. the relative density is 97% and the bending strength is above 400 MPa. The SiC particles and Al alloy matrix in the composite follow the cleavage and plastic tearing fracture modes, respectively. As the sintering temperature increases to 750℃, an intensive SiCp/Al interfacial reaction takes place to form more Al4C3 phase, resulting in the structural degradation and property reduction of the SiCp/Al composite. © 2017, Science Press. All right reserved.