Dry sliding wear behaviour of AZ91–Mg2Si–SiC hybrid composites at elevated temperatures

Abstract

The dry sliding wear behaviours of extruded AZ91–Mg2Si–xSiC composites were studied under a normal load of 20N at various temperatures of 25–250°C, using a pin-on-disc tribometer. The results showed a decrease in wear rates of samples with an increase in temperature from 100°C to 200°C by about 40–80%, due to the formation of an oxygen-rich tribo-layer on the worn surfaces. At 200°C, the wear rate of AZ91–Mg2Si–10SiC hybrid composite was 54% lower than that of AZ91–Mg2Si composite and AZ91 alloy. A mechanically mixed layer comprised of iron and magnesium oxides on the worn surface of the hybrid composite protected the surface from more wear. Oxidation and plastic deformation were dominant wear mechanisms at wear temperatures from 25°C to 200°C.