A theoretical model was suggested that describes emission of partial Shockley dislocations from triple junctions of grain boundaries in deformed nanocrystalline materials. In the framework of the model, triple junctions accumulate dislocations due to grain boundary sliding along adjacent grain boundaries. The dislocation accumulation at triple junctions causes partial Shockley dislocations to be emitted from the dislocated triple junctions and thus accommodates grain boundary sliding. Ranges of parameters  (applied stress, grain size, etc) were calculated in which the emission events were energetically favourable in nanocrystalline Al, Cu and Ni. The model accounts for the corresponding experimental data reported in the literature.

Emission of Partial Dislocations from Triple Junctions of Grain Boundaries in Nanocrystalline Materials. M.Y.Gutkin, I.A.Ovidko, N.V.Skiba: Journal of Physics D, 2005, 38[21], 3921-5