Mechanical properties and chemical bonding characteristics of WC and W2C compounds

The mechanical properties and chemical bonding features of W-C binary compounds (h-WC, o-W2C, h-W2C and t-W2C) were studied by density functional theory (DFT). It is shown that they are thermodynamically stable identified by the cohesive energy and formation enthalpy of W-C binary compounds. The elastic constants were calculated using the stress-strain method. The Voigt-Reuss-Hill approximation was used to evaluate the moduli. The surface constructions of bulk and Young's moduli were applied to illustrate the mechanical anisotropy. The population analysis of W-C binary compounds was used to discuss the chemical bonding, which indicate the combinations of covalent and metallic bonds in these compounds. Moreover, the anisotropic properties of sound velocities for W-C binary compounds were explored. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved.