Wear Resistance of Novel FeCr₂VW_0.3 Refractory Medium Entropy Alloy

High/Medium entropy materials are increasingly recognized for their potential in high-temperature applications. To enhance high temperature wear resistance, a novel medium entropy alloy, FeCr₂VW_0.3, was developed and synthesized using arc melting in an argon atmosphere. The resultant microstructure of the sintered composite exhibited a dual-phase composition of body-centered cubic (BCC) phases, with the BCC1 phase predominantly containing tungsten and the BCC2 phase enriched with vanadium. The BCC1 phase was the matrix and the BCC2 phase was distributed along the grain boundaries of the BCC1 phase. The BCC2 phase also had a much higher hardness than the BCC1 phase.

This study investigated the dry sliding behavior of the medium entropy alloy, FeCr₂VW_0.3, against a silicon nitride ceramic ball under various loads (5N, 10N, 15N, 20N, and 50N) at room temperature for a duration of 20 minutes. The wear behavior of the alloy was further evaluated at room temperature, 450°C, 550°C and 650°C, under a constant load of 20N for 20 minutes. The findings demonstrate that the medium entropy alloy exhibits superior wear resistance against the silicon nitride ceramic, attributed mainly to the high hardness of the alloy. Notably, the wear rate decreased as the temperature increased.

The primary wear mechanisms identified for FeCr₂VW_0.3 were adhesive wear at all tested temperatures, and oxidative wear at high temperatures. Plastic deformation induced grain refinement was also observed for the grains beneath the sliding track. The formation of multiple elements oxides and the presence of the hard BCC2 phase were crucial in minimizing the volume loss of FeCr₂VW_0.3 during high-temperature wear tests. The formation of metal oxides might have created a thin lubricious tribo-layer, which reduced the wear rate when testing at high temperature.