Influence of SiC additions on Mechanical Properties in the Zn-Al alloy (ZA-27)

This paper describes a study of the mechanical properties of as-cast and heat treated ZA-27 Zinc-aluminium alloy particulates containing silicon carbide (SiC) particulates of size 100–μm and of contents ranging from 0% by 6% by weight. The vortex method of production as employed in which the SiC particles were poured into the vortex created by stirring the molten metal by means of a mechanical agitator. Subsequent homogenizing heat treatment was performed at 320°C for durations of 1, 2, 3 and 4 hours, respectively. The results of this study revealed that as SiC composition was increased, there was significant increase in the ultimate tensile strength (UTS) and hard ness of the composite, accompanied by reductions inits ductility and impact strength. Heat treatment was found to improve significantly the ductility and impact strength of the composite, but cause reductions in its UTS and hardness. An attempt is made in the paper to provide explanations for these phenomena.