Calculating elastic constants in high-entropy alloys using the coherent potential approximation: Current issues and errors

Abstract

The new class of high-entropy alloys (HEAs) materials have shown interesting properties, such as high strength and good ductility. However, HEAs present a great challenge for conventional ab initio calculations and the few available theoretical predictions involve a large degree of uncertainty. An often adopted theoretical tool to study HEAs from first-principles is based on the exact muffin-tin orbitals (EMTO) method in combination with the coherent potentials approximation (CPA), which can handle both chemical and magnetic disorders. Here we assess the performance of EMTO-CPA method in describing the elastic properties of HEAs based on Co, Cr, Fe, Mn, and Ni. We carefully scrutinize the effect of numerical parameters and the impact of various magnetic states on the calculated properties. The theoretical results for the elastic moduli are compared to the available experimental values.