Prediction of structure and phase transformations

This chapter introduces calculational methods that can be used for abinitio structure prediction in multicomponent alloy systems, with an emphasis on concepts relevant to high entropy alloys. Specifically we will address density functional-based calculation of T=0K total energies. Extension to finite temperature will use cluster expansions for the energies to obtain the chemical substitution entropy that characterizes the high entropy alloy family. Additional contributions such as vibrational and electronic entropies will be included as needed. We describe molecular dynamics and Monte Carlo simulation methods, and the types of information that can be obtained from them. Example applications include three high entropy alloy families, Cr-Mo-Nb-V, Nb-Ti-V-Zr, Mo-Nb-Ta-W, and their binary and ternary subsystems.