An effective strategy to improve the tribological performance of Ni55Ti45 alloy at elevated temperatures by oxygen doping

This study investigated the effects of oxygen doping on the mechanical and tribological properties of Ni55Ti45 alloy at high temperature. It was found that adding 2 at%O increased the alloy's hardness by 22 % and reduced the friction coefficient to 0.286. At 500 °C, the wear rate of the oxygen-doped alloy was reduced to 0.38 × 10⁻⁵ mm³ /(m N), exhibiting the best wear resistance. These improvements were attributed to the in-situ formed precipitated oxide phases and glaze layer induced by the shear force during the friction process at high temperature. The wear mechanism transitioned from abrasive wear and fatigue delamination at RT to oxidation wear at 500 °C. This work demonstrated that oxygen doping is an effective strategy to improve the high temperature tribological properties of Ni55Ti45 alloy.