Repassivation and dry sliding wear behavior of equiatomic medium entropy TiZr (Hf, Ta, Nb) alloys

The repassivation behavior of equiatomic TiZr (Hf, Ta, Nb) alloys was studied by an in-situ scratch method. Among the three alloys, TiZrHf had the highest repassivation rate, followed by TiZrTa and TiZrNb. In addition, only micro-abrasive wear was found in TiZrHf, and the wear mechanism was mainly micro-abrasion and delamination in TiZrTa, whereas severe ploughing, delamination, and plastic deformation was found in TiZrNb, due to its lower hardness, resulting in TiZrNb having the highest coefficient of friction (COF) and wear rate. Tribofilm and material transfer were found in all medium entropy alloys, which was prominent in TiZrNb. The extent of work hardening induced by friction was in the following order: TiZrHf > TiZrTa > TiZrNb.

Automated summary

The repassivation behavior of equiatomic TiZr (Hf, Ta, Nb) alloys was studied. It was found that TiZrHf had the highest repassivation rate, while TiZrNb had the highest coefficient of friction and wear rate. Tribofilm and material transfer were observed in all medium entropy alloys.