Dry Sliding Wear Behavior and a Proposed Criterion for Mild to Severe Wear Transition of Mg–3Al–0.4Si–0.1Zn Alloy

Wear behavior of Mg–3Al–0.4Si–0.1Zn alloy was studied as a function of applied load and sliding speed under dry sliding conditions using a pin-on-disk configuration within 20–380 N and 0.1–4.0 m/s. An empirical wear transition map has been constructed to delineate the conditions under which severe wear initiated. The roles of microstructural evolution, hardness change in subsurface and surface oxidation on wear transition were also studied. The results indicate that the transition to severe wear occurs when the deformed microstructure in surface layer of material transforms into dynamic recrystallization (DRX) microstructure. A contact surface DRX temperature criterion for mild to severe wear transition is proposed, and the contact surface DRX temperatures are calculated using activation energy obtained by hot compression tests. A model for predicating mild to severe wear transition load has been developed based on the proposed contact surface DRX temperature criterion. The mild to severe wear transition loads are well predicted within the sliding speed range of 0.8–4.0 m/s.