Link between structural and mechanical stability of fcc- and bcc-based ordered Mg-Li alloys.

The first principles pseudopotential calculations based on the Perdew-Burke-Ernzerhof (PBE) form of generalized gradient approximation (GGA) within density functional theory (DFT) have been used to successfully investigate the electronic and elastic properties of cubic-based Mg-Li alloys. The heats of formation, Jones-type analysis and mechanical elasticity were utilized in predicting structural stability profile, and their results consistent with each other. An interesting correlation between shear modulus (C$\prime )$ and the predicted energy differences of corresponding bcc and fcc ordered compounds relative to hcp Mg and Li lattices is observed.