Ab initio investigation of mechanical and thermodynamic properties of vanadium-nitride

Abstract

Abstract Density functional theory-based calculations in combination with the continuum approach are used to study the mechanical properties of vanadium nitride (VN) and the method of Debye-Gruneisen is used to investigate its thermodynamic characteristics. Elastic constants of the structure C11 = 580.97, C12 = 205.02 and C44 = 108.92 GPa are obtained. Ductility ratio between 2.35 and 2.52 is calculated which predicts the VN compound to be malleable and structurally stable and it is categorized among tough coating materials. Also, thermodynamic behavior, bulk modulus, specific heat capacity in constant pressure and temperature expansion coefficient of VN are rigorously investigated. Results indicate that as the temperature increases, the bulk modulus decreases. At room temperature the bulk modulus reaches 294.53 GPa, at 400 K it is 284.24 GPa and finally reduces to 221.25 GPa at 1000 K. Hence, compared to the ground state calculations the bulk modulus obtained here is fairly consistent with the experimental data.