Atomistic simulation of tribology behaviors of Ti-based FeCoNiTi high entropy alloy coating during nanoscratching

Molecular dynamics (MD) simulations are performed to investigate the nanoscale tribology behavior of Ti-based FeCoNiTi High-entropy alloy (HEA) coating through nanoscratching. Three coating interface models, (001)HEA||(0001)Ti, (001)HEA||(11 2‾ 0)Ti, and (001)HEA||(1 1‾ 00)Ti, are selected to explore the effects cutting depth (D) and cutting velocity (V) of abrasive particles during the nanoscratching process. The results show that the Ti-based HEA coating with the interface (001)HEA||(0001)Ti has the smallest coefficient of friction (COF) making it most suitable as the coating interface. The increase in V resulted in the increase of the frictional force influenced by the Other structure composed of disordered atoms. Due to the existence of multiple phase structures in the limited area of the coating, dislocation nucleation is difficult and disordered atoms are formed. This is different from the strengthening caused by dislocation accumulation in the scratching region. The HEA coating plays an effective role in protecting the pure Ti substrate. With the protection of HEA coating, dislocation slip and deformation twinning were not observed in the pure Ti substrate. However, dislocation slip are the main plastic deformation mechanisms of uncoated pure Ti. These findings provide a theoretical reference for upgrading the wear resistance of pure Ti with HEA coating and expands the area of application of pure Ti.