Solution strengthening of ductile refractory HfMoxNbTaTiZr high-entropy alloys

The crystal structure, microstructure, and mechanical properties of HfMoxNbTaTiZr (x <= 1) alloys were investigated by X-ray diffraction, scanning electron microscopy, and compression testing. All the as solidified HfMoxNbTaTiZr alloys possess a simple body-centered cubic structure. Lattice parameters of the HfMoxNbTaTiZr alloys decrease with an increase in Mo concentration, but the corresponding densities show an opposite trend. The yield strength of the HfMoxNbTaTiZr 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, HfMoxNbTaTiZr (x < 1) alloys exhibit excellent room-temperature plasticity (> 50%). The material with x=0.75 is a new ductile refractory high-entropy alloy with promising mechanical properties. (c) 2016 Elsevier B.V. All rights reserved.