Atomic-Scale Study of Grain Boundary Evolution in the Abrasive Wear of An Al–Li Alloy

In the present work, the atomic-scale study of grain boundary evolution in the abrasive wear of an Al–Li alloy was conducted. The results showed that abrasive wear was one of the main wear mechanisms of the Al–Li alloy during the fretting tests. After heat treatment, the grains were refined, which led to an increase in grain boundaries. According to the molecular dynamics simulations, the increase in grain boundaries could impede abrasive wear. The migration of grain boundaries was observed during the abrasive wear. Compared with the abrasive particle sliding inside a grain, the abrasive particle sliding across grain boundaries led to more grain boundary migration. The mechanism of grain boundary migration was revealed, which was related to the formation and movement of steps between grain boundaries and grains. The movement of the Shockley partial dislocation 1/6 < 112 > resulted in the occurrence of atomic rearrangement which led to the formation and movement of steps.