Effect of Particle Size on the Microstructures and Mechanical Properties of SiC-Reinforced Pure Aluminum Composites

This article examined the effects of particle size and extrusion on the microstructures and mechanical properties of SiC particle-reinforced pure aluminum composites produced by powder metallurgy method. It has been shown that both particle size and extrusion have important effects on the microstructures and mechanical properties of the composites. The SiC particles distribute more uniformly when the ratio of the matrix powder size and SiC particle size approaches unity, and the smaller-sized SiC particles tend to cluster easily. The voids are found to coexist with the clustered and large-sized SiC particles, and they significantly decrease the density and mechanical properties of the composites. Extrusion can redistribute the SiC particles in the matrix and decrease the number of pores, thus make the SiC particles distribute more uniformly in the matrix, and enhance the interfacial bonding strength. The decrease in the SiC particle size improves the tensile strength and yield strength, but decreases the ductility of the composites.