Mobility and stability of large vacancy and vacancy–copper clusters in iron: An atomistic kinetic Monte Carlo study

Nicolas Castin, Maria Ines Pascuet, Lorenzo Malerba, Dmitry Terentyev, Giovanni Bonny

    Research outputpeer-review


    The formation of Cu-rich precipitates under irradiation is a major cause for changes in the mechanical response to load of reactor pressure vessel steels. In previous works, it has been shown that the mecha- nism under which precipitation occurs is governed by diffusion of vacancy–copper (VCu) complexes, also in the absence of irradiation. Coarse-grained computer models (such as object kinetic Monte Carlo) aimed at simulating irradiation processes in model alloys or steels should therefore explicitly include the mobil- ity of Cu precipitates, as a consequence of vacancy hops at their surface. For this purpose, in this work we calculate diffusion coefficients and lifetimes for a large variety of VCu complexes. We use an innovative atomistic model, where vacancy migration energies are calculated with little approximations, taking into account all effects of static relaxation and long-range chemical interaction as predicted by an interatomic potential. Our results show that, contrary to what intuition might suggest, saturation in vacancies tend to slow down the transport of Cu atoms.
    Original languageEnglish
    Pages (from-to)315-324
    JournalJournal of Nuclear Materials
    Issue number1-3
    StatePublished - Jun 2012

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