Simulations of decomposition kinetics of Fe-Cr solid solutions during thermal aging

TL;DR

This paper models the decomposition kinetics of Fe-Cr solid solutions during thermal aging using atomistic simulations, fitting interactions to ab initio data and experimental phase diagrams, and compares results with experimental observations.

Contribution

It introduces a new AKMC simulation approach with composition-dependent interactions fitted to ab initio and experimental data for Fe-Cr alloys.

Findings

Simulated kinetics agree with experimental data.

The model captures the sign change of mixing energy.

Provides insights into phase decomposition during aging.

Abstract

The decomposition of Fe-Cr solid solutions during thermal aging is modeled by Atomistic Kinetic Monte Carlo (AKMC) simulations, using a rigid lattice approximation with composition dependant pair interactions that can reproduce the change of sign of the mixing energy with the alloy composition. The interactions are fitted on ab initio mixing energies and on the experimental phase diagram, as well as on the migration barriers in iron and chromium rich phases. Simulated kinetics is compared with 3D atom probe and neutron scattering experiments.