Keywords

nonmetal, mixed-basis cluster expansion, Monte Carlo method, ordering

Abstract

The TiC1-xNx system has long been prized in industry because of its desirable thermodynamic and hardness characteristics. Previous studies have not produced comprehensive results describing the ordering tendencies of TiC1-xNx at any temperature. We apply the mixed-basis cluster expansion and Monte Carlo methods to the problem and find a fascinating array of ground-state structures occurring at precise nitrogen-concentration intervals of ∆x=1/16 and related to each other by simple (201) quasisuperlattice motifs. Thermodynamic Monte Carlo results indicate that the critical ordering temperatures at all concentrations are well below room temperature. short-range ordering develops at T ≈ 800 K and exhibits the characteristic motifs of the predicted ground state structures. Bulk modulus optimization is not feasible since this quantity shows little sensitivity to atomic configuration.

Original Publication Citation

Brian Kolb* and Gus L. W. Hart, "Nonmetal ordering in TiC1-xNx: Ground-state structure and the effects of finite temperature"Phys. Rev. B Phys. Rev. B 72, 22427 (19 Dec. 25). The original article may be found here: http://prb.aps.org/abstract/PRB/v72/i22/e22427