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, α₂, 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.