Ab initio predicted alloying effects on the elastic properties of Al x Hf 1-x NbTaTiZr high entropy alloys

Abstract

Using ab initio alloy theory, we investigate the equilibrium bulk properties and elastic mechanics of the single bcc solid-solution Al x Hf 1-x NbTaTiZr (x = 0-0.7, 1.0) high entropy alloys. Ab initio predicted equilibrium volume is consistent with the available experiment. We make a detailed investigation of the alloying effect of Al and Hf on the equilibrium volume, elastic constants and polycrystalline elastic moduli. Results imply that the partial replacement Hf with Al increases the stability of the bcc phase and decreases the ductility of the Al x Hf 1-x NbTaTiZr HEAs. The inner ductility of Al 0.4 Hf 0.6 NbTaTiZr is predicted by the calculations of ideal tensile strength.