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The structural properties, phase stabilities, anisotropic elastic properties and electronic structures of Cu-Ti intermetallics have been systematically investigated using first principles based on the density functional theory. The calculated equilibrium structural parameters agree well with available experimental data. The ground-state convex hull of formation enthalpies as a function of Cu content is slightly symmetrical at CuTi with a minimal formation enthalpy (-13.861 kJ/mol of atoms), which indicates that CuTi is the most stable phase. The mechanical properties, including elastic constants, polycrystalline moduli and anisotropic indexes, were evaluated. G/B is more pertinent to hardness than to the shear modulus G due to the high power indexes of 1.137 for G/B. The mechanical anisotropy was also characterized by describing the three-dimensional (3D) surface constructions. The order of elastic anisotropy is Cu 4 Ti 3 > Cu 3 Ti 2 > α-Cu 4 Ti > Cu 2 Ti > CuTi > β-Cu 4 Ti > CuTi 2 . Finally, the electronic structures were discussed and Cu 2 Ti is a semiconductor.

Using first-principles calculations based on density functional theory, the structural, electronic and thermodynamic properties of Mg2Sn in anti-fluorite structure under hydrostatic pressure are investigated. Our results for the equilibrium structural parameters are consistent with the previous experimental and theoretical data. The dependences of elastic constants, polycrystalline elastic moduli, Poisson's ratio and the anisotropy factor on pressure have been investigated. It is found that pressure has a significant effect on elastic properties due to variations in interatomic distances. In addition, the variations in density of states with applied pressure are determined to reveal the bonding characteristics. Finally, the dependences of bulk modulus and thermodynamic properties of Mg2Sn on pressure and temperature are investigated with the quasi-harmonic Debye model, and the results of thermodynamic properties are consistent with the experimental report.