Microstructure, mechanical properties and wear resistance of SiCp/AZ91 composite prepared by vacuum pressure infiltration

Abstract

SiCp/AZ91 composites were prepared by vacuum pressure infiltration. The microstructure, mechanical properties and wear resistance of composite were studied. Results indicated that SiC particles were uniformly distributed in the metal matrix and had a good interface bonding with the metal matrix. Mg17Al12 preferably precipitated near the SiC particles, and high-density dislocations were induced by the mismatch of the coefficient of thermal expansion (CTE) between the SiC particle and the AZ91 matrix, thereby accelerating the aging precipitation of the matrix. Compared with AZ91 alloy, the addition of SiC particles improves the hardness and compressive strength of the composite, which is mainly due to the load transfer strengthening and grain refinement strengthening mechanisms. Furthermore, a stable support surface-protecting matrix formed during the wear process because of the excellent wear resistance of SiC.