Theoretical exploration of structural, electronic, elastic, mechanical, and thermodynamic properties of MgCu4Sn intermetallic compound for engineering applications: first-principle calculations

Abstract

The structural, electronic, elastic, mechanical, and thermodynamic properties of the ternary MgCu₄Sn intermetallic compound are investigated by means of first-principle calculations within density functional theory (DFT), in combination with the quasi-harmonic Debye model. Local density approximation (LDA) and generalized gradient approximation (GGA) are made for electronic exchange–correlation potential energy. The lattice constant is in good agreement with experimental data. We determine the elastic constant tensor of the compound from the calculated stress–strain relation in both approximations. Once the elastic constants are obtained, the bulk modulus B, shear modulus G, Young’s modulus E, Poisson’s ratio ν, anisotropy factor A, and the ratio B/G for MgCu₄Sn compound were deduced using Voigt-Reuss-Hill (VRH) approximation. The ground-state structure of MgCu₄Sn is predicted to be thermodynamically and mechanically stable. The obtained band structure and density of states reveal metallic character of MgCu₄Sn. The calculation results show also that this intermetallic crystal is a stiff, elastically anisotropic and ductile material. The Debye temperature is also determined from elastic constants. The temperature dependence of the constant volume heat capacity Cv, the entropy S, and the volumetric thermal expansion coefficient α in a quasi-harmonic approximation have been obtained from calculated energy E as a function of the volume V of a MgCu₄Sn crystal and discussed for the first report.