Effect of extrusion and particle volume fraction on the mechanical properties of SiC reinforced Al–Cu alloy composites

This paper studied the combined effects of extrusion and reinforcement volume fraction on the mechanical properties of SiC particles reinforced Al–Cu alloy composites. It has been shown that extrusion can improve the distributed homogeneity of the SiC particles in the matrix and enhance the interfacial bonding strength of the composites. The hardness of the composites increased with increasing the volume fraction of the SiC particles, while the yield strength and tensile strength of the composites decreased with increasing the volume fraction of the SiC particles due to the particle fracture during extrusion. It has also been shown that the hardness increased with the aging time until reaching the maximum values, after which the hardness started to decrease. Fracture surface observations showed that the dominant fracture mechanism of the composites is ductile fracture of the matrix, accompanied by the pull-out of the particles from the matrix before extrusion or by the SiC particle fracture after extrusion, respectively.

Research highlights▶ Strength of composites decreases with increasing the volume fraction of the SiC particles. ▶ Hardness of composites increases with increasing the volume fraction of the SiC particles. ▶ Systematical discussion has been given to explain the abnormal strength evolution.