Atomic-size and lattice-distortion effects in newly developed high-entropy alloys with multiple principal elements

A critical issue of atomic-size effects in the new class of metallic materials, high entropy alloys (HEAs), containing multi-principal alloying elements is addressed by considering the intrinsic lattice distortion. Although the development effort on these new HEAs has revealed the potential of HEAs for elevated temperature applications, a clear physical description of lattice distortions in these advanced alloys containing different atomic sizes is still lacking at the present time. In this study, we proposed a new model to address the lattice distortion of crystalline lattices in these alloys, and a series of physical parameters to address the atomic-size difference can then be defined. The optimal parameter, alpha(2), is found to be effective in explaining the lattice distortion, intrinsic strain energy and excess entropy in HEAs, as well in other multicomponent alloy systems. (C) 2015 Elsevier Ltd. All rights reserved.