OKMC simulation of vacancy-enhanced Cu solute segregation affected by temperature/irradiation in the Fe–Cu system

The effects of annealing and irradiation on the evolution of Cu clusters in α-Fe are investigated using object kinetic Monte Carlo simulations. In our model, vacancies act as carriers for chemical species via thermally activated diffusion jumps, thus playing an important role in solute diffusion. At the end of the Cu cluster evolution, the simulations of the average radius and number density of the clusters are consistent with the experimental data, which indicates that the proposed simulation model is applicable and effective. For the simulation of the annealing process, it is found that the evolution of the cluster size roughly follows the 1/2 time power law with the increase in radius during the growth phase and the 1/3 time power law during the coarsening phase. In addition, the main difference between neutron and ion irradiation is the growth and evolution process of the copper-vacancy clusters. The aggregation of vacancy clusters under ion irradiation suppresses the migration and coarsening of the clusters, which ultimately leads to a smaller average radius of the copper clusters. Our proposed simulation model can supplement experimental analyses and provide a detailed evolution mechanism of vacancy-enhanced precipitation, thereby providing a foundation for other elemental precipitation research.