Investigation of Cu precipitation in bcc-Fe – Comparison of numerical analysis with experiment

Abstract The precipitation of bcc-Cu clusters in ferrite was modelled using a multi-scale approach. From a combination of density functional theory and phonon density of states calculations with the cluster expansion technique, the solubilities of Fe and Cu in the corresponding bcc phases were obtained consistent with reported thermodynamic assessments. From these solubilities, effective bond energies were constructed for a Monte Carlo simulation of the precipitation kinetics. With a careful definition of the precipitate phase, based on the composition of the nearest neighbour shell, good agreement was observed with the experimental results obtained with 3D-atom probe and small angle neutron scattering for the Fe alloys with 1.0 and 1.5 at.% Cu annealed at 500 °C. The kinetics simulations on the continuum scale confirm the expected atomic mixing at the precipitate/matrix interface.

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