Improving wear resistance is the most crucial property expected from metal matrix composites (MMCs). In this study, wear parameters, i.e., weight loss, wear rate, and friction coefficient of A356/ZrO2+Al2O3 with and without bismuth were evaluated using a pin-on-disc test. Hybrid composites were manufactured using the vortex technique in which reinforcement particles were added in the semi-solid state at 605±5 oC. Results show that ZrO2 and Al2O3 reinforcements were successfully embedded in the A356 matrix. The distribution of particles was more uniform in the Bi-containing composite. Bismuth addition improves wear characteristics in which weight loss, wear rate, and friction coefficient were measured at 0.0014 g, 0. 19 mm3/m, and 0.28, respectively. This can be related to the intrinsic role of bismuth lubrication and reducing the melt's surface tension. Abrasive and adhesive wear mechanisms were observed on the worn surfaces of fabricated composites.
