The effect of hydrogen on the mechanical properties of high entropy alloy TiZrHfMoNb: First-principles investigation

Abstract

In recent years, high entropy alloys (HEAs) have demonstrated potential applications in nuclear reactors. As a transmutation byproduct in fission reaction or a fuel for fusion reaction, the hydrogen may affect the mechanical properties of HEAs. In this study, the mechanical properties and thermal stability of HEA TiZrHfMoNb and its hydrides are investigated by first-principles calculations. Our results show that the HEA TiZrHfMoNb exhibits excellent ductility and high temperature resistance. After hydrogenation, the hydrides still maintain high ductility with enhanced melting temperature, suggesting that the HEA TiZrHfMoNb is a potential candidate structural material in fusion reactors. Both of hydrogen distribution and lattice distortion in TiZrHfMoNb hydrides are found to affect the mechanical strength and ductility, which is quite different from that in pure HEAs. The TiZrHfMoNb hydrides within the phase transformation region is expected to exhibit superior mechanical performance as compared to the single-phase regions.