Correlation between test temperature, applied load and wear transition of Mg97Zn1Y2 alloy

Abstract Dry sliding wear tests were performed on Mg97Zn1Y2 alloy at various temperatures of 20, 50, 100, 150 and 200 °C using a pin-on-disc wear testing machine in order to reveal mild-severe (M-S) wear transition mechanism during elevated-temperature wear testing. It was shown that at each test temperature, the wear rate increased with increasing load, and all wear rate-load curves demonstrated two distinct stages i.e. mild and severe wear stages. The predominant wear mechanisms operating in mild and severe wear stages were analyzed, and they were indicated in the mild and severe wear regimes of a wear mechanism transition map, respectively. M-S wear transition mechanism was analyzed by comparison of microstructure transformation and hardness change in subsurfaces of samples tested in mild and severe wear stages, from which M-S wear transition mechanism was confirmed as softening of surface material arising from dynamic recrystallization (DRX) microstructure transformation. The M-S wear transition load was found to have a linear relationship with test temperature, and decreased with rising test temperature. M-S wear transition obeyed a critical surface DRX temperature (SDT) criterion under given conditions, and the transition loads were estimated at various test temperatures by using the criterion.