Formation of Y[subscript 2]O[subscript 3] nanoclusters in nanostructured ferritic alloys during isothermal and anisothermal heat treatment: A kinetic Monte Carlo study

Abstract

Kinetic Monte Carlo simulations, based on parameters obtained with density-functional theory in the local-density approximation and experimental data, are used to study bulk precipitation of Y[subscript 2]O[subscript 3] in α iron. The simulation involves realistic diffusion mechanisms, with a rapid diffusion of O atoms by interstitial jumps and a slower diffusion of Fe and Y atoms by vacancy jumps, and a point defect source which drives the vacancy concentration toward its equilibrium value, during isothermal and anisothermal heat treatments. Depending on alloy and thermal history conditions, the Monte Carlo simulations predict different kinetic behavior, including transient precipitation of metastable iron oxides followed by precipitation of Y[subscript 2]O[subscript 3] nanoclusters.