First-principles calculations on elasticity and anisotropy of tetragonal tungsten dinitride under pressure

Abstract

First-principles calculations of the crystal structure and the elastic properties of tetragonal WNelastic properties, anisotropy, WNelastic properties, anisotropy, WNelastic properties, anisotropy, WN 2 have been performed with the plane-wave pseudopotential density functional theory method. The calculated structural parameters and elastic constants at zero pressure and temperature are in excellent agreement with the available theoretical results. The dependence of the elastic constants C ij, the aggregate elastic moduli B, G and the anisotropies on pressure have been investigated. WN 2 is a brittle system below about 66 GPa, whereas it becomes ductile under high pressure. By the elastic stability criteria, it is predicted that tetragonal WN 2 are not stable above 232.1 GPa. © 2012 The Japan Institute of Metals.