In this paper we continue with our previous study on Cu precipitation in Fe–Cu binary alloys [1] under irradiation. In the latter it was shown that a simple model, including growth and coarsening and assuming that the only effect of irradiation is to enhance Cu diffusion, provides a good description of the kinetics of copper matrix depletion during precipitation in Fe–Cu model alloys. In the present work, using this model, we perform a detailed study on: (a) the incidence of Cu solubility limit on precipitation kinetics; (b) the evolution of the elasticity limit and material hardness with Cu precipitation, with the help of the model of Russell and Brown, [2] and (c) the variation of the ductile–brittle transition temperature (ΔDBTT) component due to Cu precipitation, using an empiric relation between this temperature transition and hardness. Theoretical results are compared with experimental ones.