Influence of irradiation on the evolution of radiation defects in nanocrystalline FCC metals: The case of Ni

Radiation damage in materials is accompanied by generation of defects. One promising approach for describing the evolution of defects involves using chemical rate theory. We aim to study the influence of irradiation and external conditions on the evolution of radiation point defects in nanocrystalline fcc metals . We used nanocrystalline nickel for which we know the parameters as a model fcc metal. The approach can be applied to nanoparticles as well. By solving the non-stationary equations, possible dependencies of defect concentrations on irradiation time, dose, temperature and nanoparticle size have been established. It was found that there are situations where the defect concentration increases with increasing grain (or particle) size, does not depend on size, is nonmonotonic with maximum, or decreases with an inverse dependence on size. This variability is ensured by the intensity of defect interactions at external boundaries, recombinations inside the grain (particle), temperature, time (dose), and irradiation regimes.