Development of an interatomic potential for L12 precipitates in Fe–Ni–Al alloys

Abstract

Fe–Ni-based alloys have been considered as candidate structural materials for advanced nuclear reactors, and some of their excellent properties are particularly associated with L12 precipitates dispersed in the alloys. For a better understanding of the irradiation response, classical molecular dynamics is an essential tool to simulate the irradiation-induced defect formation and subsequent microstructural evolution. We here develop an interatomic potential for L12(Ni,Fe)3Al precipitates in the ternary Fe–Ni–Al system. The fitting parameters are tuned to describe the lattice and elastic constants of NiFe solid solutions and defect formation/vacancy migration energies in the fcc matrix. Furthermore, the lattice properties and defect energies of L12(Ni,Fe)3Al are considered for the fitting. We demonstrate the developed potential reproduces the lattice and defect properties with reasonable accuracy by comparison with density functional theory calculations, existing empirical potentials, and experimental data. This potential will be useful to investigate the defect formation and evolution of (Ni,Fe)3Al precipitates in the alloys under irradiation, which would provide critical insights into the materials design strategy to achieve enhanced properties.