Abstract:Magnesium alloy matrix composites(MMC) with volume fractions of 15%, 20%, 25% and 30% were fabricated by squeeze cast using crystallized aluminum silicate short fibers as reinforcement and aluminum phosphate as binder under high temperature, respectively. The dry sliding tribological properties of the magnesium alloy matrix composites were studied using MM200 wear tester (block-on-ring configuration) against a hardened alloy steel counterface with hardness of HRC53 under loads of 10, 20, 30, 40 and 50 N and sliding velocities of 0.47 and 0.92 m/s. The effects of applied loads on the dry sliding tribological properties of Al₂O₃∙SiO_2(sf)/AZ91D composites with different volume fractions were investigated. The examinations on the work surface of wear test specimens were conducted by scanning electron microscopy(SEM). The results show that, the wear mechanism of the composite changes with changing applied loads under sliding speed of 0.47 m/s. But the wear mechanism does not change under sliding speed of 0.94 m/s. The effect of sliding speeds on wear rate of the MMCs specimens is greater and more complex than that of the AZ91D matrix alloy. The relationship between wear rate and volume fraction of the composite is influenced by applied loads and sliding speeds under dry friction.

Key words: aluminium silicoate fiber; magnesium matrix composite; applied load; volume fraction; wear rate