Effects of T4 and T6 Heat Treatments on the Wear Behaviour of WC-Reinforced Mg Alloy Matrix Composite

Collective outcomes of WC particle reinforcement and heat treatment on the dry sliding wear rate of AZ91 magnesium metal matrix composite have been presented. The vacuum-assisted semi-solid stir casting method was employed to fabricate the composites. Wear study was conducted on the specimens using a pin-on-disc tribometer with EN8 steel as a counter material. The experiments were designed using Taguchi L27 array, with control factors viz. applied load (20, 40 and 60 N), sliding speed (1, 2 and 3 m/s), heat treatment (no treatment, T4 and T6) and WC wt% (0, 1.5 and 3). Energy-dispersive X-ray spectroscopy and scanning electron microscopy analyses were performed to study the surface of the tested specimens. T6-treated AZ91/3.0WC composite showed 63% enhanced resistance to wear due to the presence of beta-phase (Mg17Al12) precipitation during the heat treatment process and WC reinforcements.