Semi-Empirical Force-Field Model for the Ti1−xAlxN (0 ≤ x ≤ 1) System

• Main Authors: G. A. Almyras, D. G. Sangiovanni, K. Sarakinos
• Format: Article
• Language: English
• Published: MDPI AG 2019-01-01
• Series: Materials
• Subjects: titanium-aluminum nitride; Ti-Al-N; MD simulations, molecular dynamics; interatomic potential; MEAM; force-field model; spinodal decomposition; phase stability
• Online Access: http://www.mdpi.com/1996-1944/12/2/215

We present a modified embedded atom method (MEAM) semi-empirical force-field model for the Ti1−xAlxN (0 ≤ x ≤ 1) alloy system. The MEAM parameters, determined via an adaptive simulated-annealing (ASA) minimization scheme, optimize the model’s predictions with respect to 0 K equilibrium volumes, elastic constants, cohesive energies, enthalpies of mixing, and point-defect formation energies, for a set of ≈40 elemental, binary, and ternary Ti-Al-N structures and configurations. Subsequently, the reliability of the model is thoroughly verified against known finite-temperature thermodynamic and kinetic properties of key binary Ti-N and Al-N phases, as well as properties of Ti1−xAlxN (0 < x < 1) alloys. The successful outcome of the validation underscores the transferability of our model, opening the way for large-scale molecular dynamics simulations of, e.g., phase evolution, interfacial processes, and mechanical response in Ti-Al-N-based alloys, superlattices, and nanostructures.