Abstract The microstructure, mechanical, and high-stress abrasive wear of as-cast and heat-treated LM25-SiC composites were compared with those of a matrix alloy and a low-cost hypereutectic alloy (LM30). The microstructure of the composite exhibits uniformly dispersed SiC particles and good interfacial bonding between the SiC particles and the matrix. Heat treatment caused the needle-shaped silicon to become spherical and improved the homogeneity of its dispersion in the matrix. The hardness, ultimate tensile strength, yield strength, and wear resistance of the materials were improved, but the elongation was reduced as a result of the heat treatment. The wear rate and friction coefficient of the materials decreased as the sliding distance increased for both the as-cast and heat-treated samples. The wear surface morphology and wear debris analyses were performed by using high-resolution field emission scanning electron microscopy.