Microstructure, mechanical properties and high-temperature sliding wear response of a new Al_0.5CrFeNiV_0.5 high-entropy alloy

In this study, a new V-containing high-entropy alloy (HEA) with the chemical composition of Al_0.5CrFeNiV_0.5 has been developed. Its microstructural features and phase constitutions were investigated by several techniques, including X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The as-cast Al_0.5CrFeNiV_0.5 HEA exhibits an average Vickers hardness of around 570.5 HV, a compressive strength of about 2.53 GPa and a plasticity of around 22.1 %. In addition, the HEA still exhibits very high compressive strength of about 1218.6 MPa at 600 °C, but it decreases quickly to around 586 MPa at 700 °C and 301 MPa at 800 °C. On the other hand, high-temperature sliding wear tests of as-cast HEA against the Si3N4 ceramic balls revealed a slight change of friction coefficient in a range of 0.4–0.5 between RT and 800 °C. However, the wear rate of HEA was found to increase monotonically with increasing the temperature, and was particularly higher when temperature exceeded 600 °C. The associated mechanisms have been discussed in details based on chemical composition analysis, worn surface morphology observations as well as the characterizations of the wear track cross-sections.