| A theoretical model is suggested which describes nanoscale amorphization near crack tips in pre-cracked nanocrystalline and ultrafine-grained solids under a mechanical load. Within the model, the amorphization processes are associated with splitting transformations of grain boundary (GB) disclinations whose formation is initiated by GB sliding in a solid. The nanoscale amorphization carries local plastic deformation, releases in part high local stresses near crack tips and thus hampers crack growth in nanocrystalline and ultrafine-grained solids. |
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