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

• Autores: Castin, N.; Pascuet, Maria Ines Magdalena; Malerba, L.
• Año de publicación: 2012
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Monte Carlo; Fe-Cu; Difusion; Atomistic Simulation
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

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 toslow down the transport of Cu atoms.
Fil: Castin, N.. Centre d’Etudes de l’énergie Nucléaire; Bélgica
Fil: Pascuet, Maria Ines Magdalena. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Fil: Malerba, L.. Centre d’Etudes de l’énergie Nucléaire; Bélgica