Disclinations due to grain boundary relaxation in fine-grained materials and thin films

Two simple two-dimensional grain structures have been analyzed with respect to potential disclination formation. Partial disclinations may form at triple-line junctions where three grains meet. The driving force for disclination formation is the relaxation of interfacial energy. We conclude that 1. The expected (average) disclination strength is inversely proportional to the grain size (Eqs. 4,5). 2. The proposed mechanism can be effective in ultrafine-grained materials with a grain size equal or less than 1μm. 3. The presence of partial disclinations at triple-line junctions may well affect material properties such as the resistance of aluminum lines against electromigration damage. 4. There is a minimum misorientation for small angle grain boundaries in ultrafine-grained materials. This minimum misorientation corresponds to the disclination strength (Eqs. 4,5).