Microstructure and Wear Properties of ZrO₂ Particle Reinforced Magnesium-based Composites Prepared by Powder Metallurgy

AZ91 magnesium matrix composites with different mass fraction zirconia（ZrO₂） particles reinforced by powder metallurgy were prepared. The microstructure, hardness, density and wear resistance of the composite were studied by scanning electron microscope（SEM）, energy dispersive spectrometer（EDS）, X-ray diffractometer（XRD） and hardness tester.The results show that condensation may occur in ZrO₂ particles under normal conditions. Mg and Mg₁₇Al₁₂ are included in the structure of the composite in addition to the ZrO₂. The addition of ZrO₂ particles can effectively improve the hardness and wear resistance of ZrO₂/AZ91 composites. The hardness of the 30wt% ZrO₂/AZ91 composite is 108.7 HV. Compared with the matrix AZ91 alloy, the hardness increases by about 22%. The wear rate of 30wt%ZrO₂/AZ91 composites under 20 N load is 176.2 mm³/（N·m）. Compared with the matrix AZ91 alloy, the wear rate decreases by about 28%. The main wear mechanism of the composites is abrasive wear and oxidation wear.