Simple Parameterization of Embedded Atom Method Potentials for FCC Alloys

We extend our simple parametric form for Embedded Atom Method interatomic potentials for FCC metals [Daw & Chandross, “Simple Parameterization of Embedded Atom Method Potentials FCC Metals”] to treat alloys. Using this model, which we refer to as “ EAM-X”, we study the generic dependence of alloy properties on the model parameters. We introduce the idea of spread alloys, where the constituent elements are defined as parametric perturbations from a central, “average” FCC metal, and where different alloys are quantified by a measure of the magnitude of the perturbation. As an example, we consider a spread binary where the only differences between the constituent elements are lattice mismatch and the cross-interaction parameters and show that the model robustly describes the clustering and ordering tendencies of metal alloys. We use the model to prove a general theorem of “parametric simplicity” in random equimolar alloys: alloy properties differ from a simple rule of mixtures in a way that depends only on the standard deviation among the constituent parameters but are otherwise not dependent on the number of constituents, consistent with previous theoretical results.