Probing the effect of ordered carbon vacancy on the thermophysical properties of VC1-x: A comprehensive first-principles calculations.

Vanadium carbides (VC 1-x) exhibit stoichiometric flexibility due to the presence of various carbon vacancies, which significantly influence their fundamental physical properties. Despite this, a comprehensive understanding of how carbon vacancies affect the mechanical and thermal properties of vanadium carbides remains elusive. Previous research has primarily focused on stoichiometric VC and has yet to fully explore the impact of carbon vacancies. This study reveals that stoichiometric VC is less stable when compared to ordered substoichiometric VC 1-x and employs first-principles calculations to obtain thermodynamic, mechanical, and transport properties of VC 1-x. The ordered carbon vacancy leads to an increase in the V–V bond density and volume. Due to the anharmonic effect, the ordered carbon vacancy impairs heat capacity and thermal expansion. The hardness and toughness decrease with increasing carbon vacancy concentrations. The Boltzmann transport equation is used to calculate electrical and thermal transport properties, which shows that growing scattering effects reduce thermal transport capacity. The results provide accurate data support for vanadium carbide research and theoretical support for designing ultra-high temperature ceramic materials. [ABSTRACT FROM AUTHOR]