Microstructure and Mechanical Properties of SiC_p/AZ91 Composites Prepared by RS/PM Process

SiCp/AZ91 composite bars were fabricated by rapid solidification/powder metallurgy(RS/PM) process.Effect of SiC content on the microstructure and mechanical properties of SiCp/AZ91 composites was investigated.The results show that the silicon carbide particulates(SiCp) were uniformly dispersed in the AZ91 magnesium alloy matrix,but agglomeration or clustering of the reinforcing SiC was observed at random intervals.The mechanical properties of the composites such as tensile strength,yield strength and elongation all degraded with the increase of SiC content.The Mg2Si appeared to originate on the surface of SiC and Mg matrix due to the reactions between the Mg,SiC and SiO2,which finally led to the early debonding between the reinforcement and the matrix.