Valence electron density based temperature-dependent properties of ultra-high temperature (Ti1-xNbx)C solid solutions

In order to understand the mechanical, thermal and chemical properties of ultra-high temperature materials, which are crucial for the extreme environment applications, the valence electron density based temperature-dependent properties of ultra-high temperature (Ti_1-xNb_x)C have been investigated in this study. The obtained results demonstrated that the temperature-dependent work function, thermionic emission, electrical resistivity of (Ti_1-xNb_x)C were dominated by the free valence electron density. The temperature-dependent bulk modulus, solid solution strengthening or softening, melting point temperature of (Ti_1-xNb_x)C were dominated by the average localized valence electron density. Moreover, above the brittle-to-ductile (BTD) temperature, due to the fact that dislocation motion is mediated by the kink atom propagation, the hot hardness of (Ti_1-xNb_x)C at high temperature was dominated by the localized valence electron density on the kink atoms, i.e. carbon atoms. The valence electron density based temperature-dependent properties of (Ti_1-xNb_x)C, will pave the way towards the performance-oriented design of advanced ultra-high temperature materials, where the optimized mechanical, thermal and chemical properties can be rationally tailored at electronic scale.