Alloying effects of Zr, Nb, Ta, and W on thermodynamic and mechanical properties of TiC based on first-principles calculation

Abstract

First-principles calculation has been used to study the temperature-dependent thermodynamic and mechanical properties of TiC with additions of transition metal elements through the combination of quasi-harmonic Debye model and thermal electronic excitation. It is found that the substitution behaviors of Zr, Nb, Ta, and W doped into TiC are not only structurally stable, but also would increase its melting temperature. To further determine the alloying effects, the mechanical parameters of doped TiC at finite temperatures have been established by means of ductility, Vickers hardness, fracture toughness, and machinability damage tolerance, from which we reveal that it is feasible to substitute Ti by W in TiC. The computed results are in good agreements with experimental observations in the literature, and are discussed in terms of electronic structures and bond characteristics.