2012 Volume 53 Issue 7 Pages 1247-1251
First-principles calculations of the crystal structure and the elastic properties of tetragonal WN2 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 Cij, the aggregate elastic moduli B, G and the anisotropies on pressure have been investigated. WN2 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 WN2 are not stable above 232.1 GPa.