Solution strengthening of ductile refractory HfMoxNbTaTiZr high-entropy alloys

Abstract The crystal structure, microstructure, and mechanical properties of HfMo x NbTaTiZr (x≤1) alloys were investigated by X-ray diffraction, scanning electron microscopy, and compression testing. All the as-solidified HfMo x NbTaTiZr alloys possess a simple body-centered cubic structure. Lattice parameters of the HfMo x NbTaTiZr alloys decrease with an increase in Mo concentration, but the corresponding densities show an opposite trend. The yield strength of the HfMo x NbTaTiZr alloys increases from 1015 MPa to 1512 MPa as x increases from 0 to 1. The solid solution strengthening is linearly proportional to a Mo concentration suggesting that the strengthening effect from each Mo atom is additive. Except for the HfMoNbTaTiZr alloy, HfMo x NbTaTiZr (x 50%). The material with x=0.75 is a new ductile refractory high-entropy alloy with promising mechanical properties.