Microstructure, Mechanical Properties and Wear Behaviour of Semisolid Stir Casting SiC Reinforced Zn-40Al Based Composites

The Zn-40Al composites with various contents of SiC were fabricated by the semi-solid stir casting process. The influence of the SiC on the microstructure, mechanical properties and wear behavior of the composites were investigated. Microstructure analysis shows that the microstructures of as-cast Zn-Al alloys are refined by the addition of SiC. However, with the increase of SiC content, a number of shrinkage porosity occur. The hardness of the composites increases with the increase content of SiC. The tensile strength of the composites declines significantly with the increase content of SiC. The most effective strengthening achieves in Zn-40Al/0.5wt.% SiC, with a maximum increment of 20% in tensile strength compared to non-SiC addition alloy. The overall results reveal that the composites possess similar friction coefficients but the abrasion loss is reduced to less than a tenth after adding 0.5% SiC.