Interatomic potentials for alloys: Fitting concentration dependent properties

Abstract

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.

Keywords:

• interatomic potential
• embedded atom method
• Finnis–Sinclair
• two-band model
• concentration dependent model
• disordered systems

Acknowledgements

This research has received partial funding from the European Atomic Energy Community's 7th Framework Programme (FP7/2007-2011), under grant agreement number 212175 (GetMat project). The work was also partially sponsored by the Belgo-Argentine MINCYT-FWO bilateral cooperation agreement, Project FW/07/EXII/002. RCP acknowledges support from CONICET-PICT 5062.