Ab InitioStudy of Phase Equilibria inTiCx

Abstract

The phase diagram for the vacancy-ordered structures in the substoichiometric ${\mathrm{TiC}}_x$ ( $x=0.5\mathrm{}–1.0$) has been established from Monte Carlo simulations with the long-range pair and multisite effective interactions obtained from ab initio calculations. Three ordered superstructures of vacancies ( ${\mathrm{Ti}}_2\mathrm{C}$, ${\mathrm{Ti}}_3{\mathrm{C}}_2$, and ${\mathrm{Ti}}_6{\mathrm{C}}_5$) are found to be ground state configurations. Their stability has been verified by full-potential total energy calculations of the fully relaxed structures.