Mechanical Properties and Abrasive Wear Behaviour of Al-SiC Composite

This study examined the microstructure, mechanical and abrasive wear of as-cast and T6 heat-treated LM25 + 10% SiC composite by comparing its properties with those of its matrix alloy and low-cost high-silicon alloy (LM30). The microstructure of the composite was found to exhibit uniformly dispersed SiC particles, as well as good interfacial bonding between the SiC particles and the matrix. Heat treatment caused the needle-shaped silicon to become more spherical, and improved the homogeneity of its dispersion in the matrix. The hardness, ultimate tensile strength, yield strength and wear resistance were improved, but the elongation was reduced as a result of the heat treatment. The wear rate and frictional coefficient decreased with an increase in the sliding distance in both as-cast and heat-treated condition. The results clearly show that the composite may not be replaced with the low-cost high-silicon Al-Si (LM30) alloy in high-stress abrasive wear situations, generally encountered in automotive components. This is a specific practical finding that may be of direct interest to the practitioner engaged in industrial application of cast MMCs.