The problem of the formation of decomposition zones in nano-grains, via the generation of non-equilibrium vacancies by boundaries (when volume sinks for them were absent) was solved. Two space-time scales were revealed. One characterized the anomalous diffusion of the components which were responsible for the occurrence of comparatively narrow adjacent boundary regions having an altered concentration, and the other controlled the diffusion proper of vacancies which reached distances that were significantly far from the boundary.

Diffusion Decomposition of Nanocrystalline Alloys at Generation of Non-Equilibrium Vacancies on Grain Boundaries. V.L.Gapontzev, A.G.Kesarev, A.Y.Yermakov, V.V.Kondratyev: Journal of Metastable and Nanocrystalline Materials, 2000, 8, 609-14