The elastic and thermodynamic properties of ZrMo2 from first principles calculations

Abstract

The elastic and thermodynamic properties of ZrMo2 under high temperature and pressure are investigated by first-principles calculations based on pseudopotential plane-wave density functional theory (DFT) within the generalized gradient approximation (GGA) and quasi-harmonic Debye model. The calculated lattice parameters are in good agreement with the available experimental data. The calculated elastic constants of ZrMo2 increase monotonically with increasing pressure, and the relationship between the elastic constants and pressure show that ZrMo2 satisfies the mechanical stability criteria under applied pressure (0–65GPa). The related mechanical properties such as bulk modulus (B), shear modulus (G), Young’s modulus (E), and Poisson’s ratio (v) are also studied for polycrystalline of ZrMo2. The calculated B/G value shows that ZrMo2 behaves in a ductile manner, and higher pressure can significantly improve the ductility of ZrMo2. The pressure and temperature dependencies of the relative volume, the bulk modulus, the elastic constants, the heat capacity and the thermal expansion coefficient, as well as the Grüneisen parameters are obtained and discussed by the quasi-harmonic Debye model in the ranges of 0–1800K and 0–65GPa.