Tribological properties and wear mechanisms of Ti_xVNbTaW_y RHEAs sliding against Si₃N₄ ceramic balls: The effects of Ti and W contents

Three new Ti_xVNbTaW_y RHEAs with different contents of Ti and W were prepared by mechanical mixing and spark plasma sintering. The effects of Ti and W contents on the mechanical and tribological properties were explored, with a focus on the wear mechanisms of the alloys sliding against Si₃N₄ ceramics from room temperature to 900 °C. The results showed that all three alloys exhibited high compressive strength and plastic strain of > 12% at room temperature. More crucially, the wear rate of the optimized alloy can be as low as 6.8 × 10⁻⁶ mm³/(N·m) at 600 °C. Friction-induced subsurface strengthening and the formation of continuous oxide films and plastic deformation layers played an important role in reducing the wear rate.