Mechanical properties and point defects of MC (M=Ti, Zr) from first-principles calculation

Abstract

First-principles calculation was performed to systematically investigate mechanical properties and point defects of stoichiometric B1 MC (M = Ti, Zr). The stress-strain relations of MC (M = Ti, Zr) under various tensile and shear loading directions were discussed, and it is found that TiC has a higher ideal strength and mechanical properties than ZrC. Our Calculation also revealed that the temperature has different effects on the formation of carbon vacancy in MC (M = Ti, Zr), i.e., the increase temperature of TiC induces the decrease of formation energy of carbon vacancy, and the increase temperature of ZrC has almost negligible effects on the formation energy of carbon vacancy. The derived results agree well with experimental observations in the literature, and provide a deep understanding to the excellent performances of transition metal carbides.