Kinetic Monte Carlo simulations, based upon parameters obtained from density-functional theory in the local-density approximation and experimental data, were used to study bulk precipitation of Y2O3 in α iron. The simulation involved 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 drove the vacancy concentration toward its equilibrium value, during isothermal and anisothermal heat treatments. Depending upon alloy and thermal history conditions, the Monte Carlo simulations predicted different kinetic behavior, including transient precipitation of metastable iron oxides followed by precipitation of Y2O3 nanoclusters.

Formation of Y2O3 Nanoclusters in Nanostructured Ferritic Alloys during Isothermal and Anisothermal Heat Treatment: a Kinetic Monte Carlo Study. C.Hin, B.D.Wirth, J.B.Neaton: Physical Review B, 2009, 80[13], 134118