Study On Wear Behaviors And Wear Mechanism Of Al₃Ti/Mg Composite

Al₃Ti/Mg composite has been synthesized by the powder metallurgy of Mg-Al-Ti system. Then wear tests of the Al₃Ti/Mg composite were carried out on a high-temperature wear machine. The wear behaviors of 25 vol. % Al₃Ti/Mg composite were systematically studied under various test conditions in comparison with AZ91D magnesium alloy. The phase and microstructures of the composite as well as the morphology, compositions and structure on worn surfaces, sections and debris were investigated using scanning electron microscope (SEM), energy dispersive spectrum (EDS) and X-ray diffraction (XRD). The wear mechanism of the composite was also discussed.The results showed that the content of Al₃Ti had an obvious influence on the wear resistance of the Al₃Ti/Mg composite. 25 vol. % Al₃Ti/Mg composite presented the best wear resistance were done. Under various ambient temperatures, the composite revealed the different wear behaviors. At room temperature, the composite possessed lower wear rates under the low load (less than 100 N), on the contrary, higher wear rate than AZ91D alloy under the high load. However, at 200℃, the composite presented an absolutely higher wear resistance than AZ91D alloy. The wear mechanisms of the composite were ascertained to be complex mechanism including abrasive wear, delamination wear, oxidation wear and adhesive wear. It was found that there a thick and hard MML would form on worn surfaces to reduce wear rate and improves wear resistance of composite effectively. The interaction of Al₃Ti particles and MML could relieve thermal softening and plastic deformation of the substrate, thus increasing the wear resistance of the composite.