A theoretical model was suggested which described the generation of lattice perfect, lattice partial and grain boundary dislocation loops at pre-existing dislocation loops in mechanically loaded nanocrystalline materials. The energy characteristics of various modes of the dislocation-loop generation were calculated and compared. With these calculations and comparison, the two basic ranges of the grain size in nanocrystalline materials were revealed each was characterized by its specific set of effectively operating modes of the dislocation-loop generation and plastic deformation. The role of the dislocation-loop generation in plastic and superplastic deformation processes in nanocrystalline materials was considered.

Generation of Dislocation Loops in Deformed Nanocrystalline Materials. M.Y.Gutkin, I.A.Ovidko: Philosophical Magazine, 2006, 86[11], 1483-511