Elastic anisotropies and thermal properties of cubic TMIr (TM=Sc, Y, Lu, Ti, Zr and Hf): A DFT calculation

Structural properties, phase stabilities, elastic properties and Debye temperatures of cubic TMIr (TM = Sc, Y, Lu, Ti, Zr and Hf) compounds were investigated by first-principles calculations. The calculated lattice parameters and formation enthalpies agree well with the reported experimental data, indicating the reliability of this work. Polycrystalline elastic modulus, Poisson's ratio and Debye temperature were calculated based on single-crystal elastic constants. The elastic anisotropy of TMIr was evaluated by elastic anisotropy indexes, surface constructions and projections, and polar plots of elastic modulus. The elastic anisotropy is in a sequence of ZrIr > HfIr > TiIr > LuIr > YIr > ScIr. Furthermore, Debye temperature and the anisotropy of sound velocity of the TMIr were also calculated and discussed. (paper)