First-Principles Study on Stability and Mechanical Properties of Cr7C3

The lattice parameters, the stability, mechanical properties and the anisotropic sound velocity of hexagonal and orthorhombic Cr7C3 were investigated using first-principles calculations. The results of the cohesive energy and the formation enthalpy of these compounds indicate that they have thermodynamically stable structures. The elastic constants and the mechanical moduli of these compounds were estimated using the stress-strain method and Voigt-Reuss-Hill approximation, respectively. Moreover, the anisotropic properties of sound velocities and mechanical anisotropies of Hexa-Cr7C3 and ortho-Cr7C3 were explored.