Continuum Separation of Nanoscale Phase in Thermal Aging Fe-Cr Alloys: Phase-Field Simulation and Experiment

The separation of Cr-enriched phase in Fe-(25-45)at.% Cr alloys is studied from the metastable region to the unstable region. The three-dimensional phase-field simulation shows a similar morphology with the transmission electron microscopy micrographs, and the quantitative simulation of particle size and particle number density have a good accordance with the present and the referred experimental results, with the microhardness of the alloy increasing simultaneously with the simulated volume fraction of the phase. The mechanisms of phase separation were clarified by the interface composition evolution of the / phase, and a transitional characteristic from nucleation and growth to spinodal decomposition is shown in the 30at.% Cr alloy aged at 750K. The combination of quantitative simulation and experimental results demonstrates the ability of the phase-field model to perform high-throughput simulations for kinetics evolution in the alloys with phase separation.