Elastic and mechanical properties of Mg3Rh intermetallic compound:An ab initio study

In this work, density functional theory plane-wave pseudo potential method, with local density approximation (LDA) and generalized gradientapproximation (GGA) are used to investigate the structural, elastic, mechanical and thermodynamic properties of the intermetallic compoundMg3Rh. Comparison of the calculated equilibrium lattice constants and experimental data shows very good agreement. The elastic constants weredetermined from a linear fit of the calculated stress-strain function according to Hooke’s law. From the elastic constants, the bulk modulus B, shearmodulus G, Young’s modulus E, Poisson’s ratio σ, anisotropy factor A, the ratio B/G and the hardness parameter H for Mg3Rh compound areobtained. Our calculated elastic constants indicate that the ground state structure of Mg3Rh is mechanically stable. The calculation results showthat this intermetallic crystal is stiff, elastically anisotropic and ductile material. The sound velocities and Debye temperature are also predictedfrom elastic constants. This is the first quantitative theoretical prediction of these properties.