Solid-Liquid Phase Diagrams for Binary Metallic Alloys: Adjustable Interatomic Potentials

TL;DR

This paper introduces a new method for modeling binary metallic alloy phase diagrams using adjustable interatomic potentials, enabling continuous variation of material properties in simulations to better understand alloy behaviors.

Contribution

The authors develop a novel approach combining LJ-EAM potentials with Gibbs-Duhem integration to accurately reproduce and systematically study binary alloy phase diagrams.

Findings

Successfully reproduces experimental phase diagrams without intermetallic phases

Demonstrates the effect of atomic size and cohesive energy on phase diagrams

Provides a method for continuous property variation in atomistic simulations

Abstract

We develop a new approach to determining LJ-EAM 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 accurately reproduction of experimental phase diagrams, but rather to provide a method by which material properties can be continuously changed in simulations 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.