An alternative DFT-based model for calculating structural and elastic properties of random binary HCP, FCC and BCC alloys: Mg–Li system as test case

Abstract

Density functional theory based ab- initio total energy calculations are used to determine the concentration dependences of equilibrium lattice parameters, densities, mixing energies (phase stability) and elastic constants of binary random Mg 1− x Li x alloys spanning the entire concentration range, in the HCP, FCC and BCC structures. A model for predicting phase stability and elastic properties of random alloys is proposed. The current model is applied to binary Mg–Li system as a test study. The predicted phase stability trends at 0 K resemble those observed experimentally in Mg–Li phase diagram, more especially at lower temperatures. The proposed model for random alloys is not only accurate but also less computationally expensive compared to traditional supercell approach.