Tribocorrosion behavior of TiZrHfNb-based refractory high-entropy alloys

Refractory high-entropy alloys (RHEAs) have superior mechanical performance at high temperature, excellent wear resistance and corrosion resistance. They are promising candidates for applications in marine equipment, which warrants further studies in tribocorrosion. The TiZrHfNb-based RHEAs were prepared and their phase, microstructure and hardness were examined. The tribocorrosion behaviors of TiZrHfNb-based RHEAs against Si3N4 balls under OCP and -0.4VAg/AgCl conditions in 3.5 wt% NaCl solution were investigated and compared with dry sliding. The results show that TiZrHfNb-based RHEAs are of single BCC structure and the hardness increase with lattice distortion. The addition of Ta and Mo in TiZrHfNb-based RHEAs can effectively improve their corrosion and wear resistance, which is attributed the formation of passivation film and increase of hardness. The wear and corrosion of TiZrHfNb-based RHEAs under -0.4VAg/AgCl condition is slightly higher than that under OCP condition. The tribocorrosion involves both electrochemical and mechanical interaction, and the TiZrHfNb1.83Mo1.83 shows the best tribocorrosion property.