A first-principles study on elastic properties and stability of TixV1-xC multiple carbide

The structure, stability and elastic properties of di-transition-metal carbides TixV1-xC were investigated by using the first-principles with a pseudopotential plane-waves method. The results show that the equilibrium lattice constants of TixV1-xC show a nearly linear reduction with increasing addition of V. The elastic properties of TixV1-xC are varied by doping with V. The bulk modulus of Ti0.5V0.5C is larger than that of pure TiC, as well as Ti0.5V0.5C has the largest C-44 among TixV1-xC (0 <= x <= 1), indicating that Ti0.5V0.5C has higher hardness than pure TiC. However, Ti0.5V0.5C presents brittleness based on the analysis of ductile/brittle behavior. The Ti0.5V0.5C carbide has the lowest formation energy, indicating that Ti0.5V0.5C is more stable than all other alloys.