Interatomic potentials for alloys: Fitting concentration dependent properties

A detailed analysis of the embedded atom method and Finnis–Sinclair formalisms is performed, showing their limitations to fit concentration dependent properties of alloys. Two empirical extensions of the former methods, so-called two-band model and concentration dependent model, are analysed in depth, and their heuristic equivalence is shown. An algorithm is proposed for the two-band model, capable of fitting concentration dependent properties of the alloy, such as mixing enthalpy and bulk modulus. The algorithm is then applied to the Fe-Cr system, deriving two interatomic potentials that closely reproduce Fe-Cr’s complex mixing enthalpy.