Wear Behavior Of AM60B Magnesium Alloy

AM60B magnesium alloy is one of the most widely used magnesium alloys. However,the investigations on its wear behavior are very scarce.Studies on wear behavior and performance of AM60B magnesium alloys have an important theoretical significance and an engineering value.Dry sliding wear tests were performed on AM60B magnesium alloy as well as the one after T5 heat treatment using a pin-on-disc wear machine in different experimental conditions.Scanning electron microscopy(SEM),energy dispersive spectrum(EDS) and X-ray diffractometer (XRD) were used to characterize the morphology,microstructure and phase of worn surface,worn section and wear debris.The wear mechanism of AM60B magnesium alloy was also discussed.The experimental results show that the wear loss increased with an increase in the load.A mild-to-severe wear transition occurred during wear.The critical load from mild-to-severe reduced with the ambient temperature increasing.The critical load was 275 N at room temperature,150 N at 100℃,and 50 N at 200℃,respectively.The wear loss of AM60B magnesium alloy after T5 heat treatment was slightly lower than that of as-cast magnesium alloy,meanwhile their wear behaviors were similar.There was a mechanical mixing layer(MML) containing the mixture of Mg and oxides,which presented a significant influence on wear behavior and wear mechanism.The thick MML would effectively reduce wear loss.The different oxides were formed under different loads and ambient temperatures;Mg-Al-O,MgO and MgAl₂O₄ appeared in sequence with an increase in the loads.A mild wear regime and a sever wear regime prevailed,respectively.The mild wear regime was classified as four different mechianisms:abrasion,oxidation,delamination and adhesion wear. Thermal softening was a predominated wear mechianism in the severe wear regime. The mixed mechianism prevailed under different loads and ambient temperatures.