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

Three new TixVNbTaWy 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 degrees 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 x 10(-6) mm3/(N.m) at 600 degrees 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.