Solid-liquid phase diagrams for binary metallic alloys: Adjustable interatomic potentials

Abstract

We develop an approach to determining Lennard-Jones embedded-atom method potentials for alloys and use these to determine the solid-liquid phase diagrams for binary metallic alloys using Kofke's Gibbs-Duhem integration technique combined with semigrand canonical Monte Carlo simulations. We demonstrate that it is possible to produce a wide range of experimentally observed binary phase diagrams (with no intermetallic phases) by reference to the atomic sizes and cohesive energies of the two elemental materials. In some cases, it is useful to employ a single adjustable parameter to adjust the phase diagram (we provided a good choice for this free parameter). Next, we perform a systematic investigation of the effect of relative atomic sizes and cohesive energies of the elements on the binary phase diagrams. We then show that this approach leads to good agreement with several experimental binary phase diagrams. The main benefit of this approach is not the accurate reproduction of experimental phase diagrams, but rather to provide a method by which material properties can be continuously changed in simulation studies. This is one of the keys to the use of atomistic simulations to understand mechanisms and properties in a manner not available to experiment. © 2007 The American Physical Society.