Impacts of SiC on the microstructure and wear performances of (SiC–Al₃Ti)/7075 composites

The influences of hybrid particles silicon carbide (SiC) and Al₃Ti on the micromorphology, density, porosity, hardness and wear properties of hybrid 7075 aluminum (Al) composites fabricated through the stir-casting method were examined. In the case of fixed addition of titanium (Ti) to the hybrid 7075 material, the results show that the particle size of in-situ-formed Al₃Ti alloy decreases gradually with the increase in silicon carbide addition. The density of composites first increases and then decreases with increasing silicon carbide particle content, and the porosity increases due to a certain amount of gas in the small and complex channels within the aggregates. The hardness increases with the addition of silicon carbide. Moreover, (SiC–Al₃Ti)/7075 hybrid composites exhibit a lower wear rate than the 7075 alloy and Al₃Ti/7075 composites. Compared with the wear rate of the alloy substrate, that of 5 wt% silicon carbide (SiC–Al₃Ti)/7075 hybrid composites decreases by 17% at 15 N and 200 m sliding distance.