The dislocation structures of a low-angle tilt grain boundary in alumina bicrystal were investigated by transmission electron microscopy. The grain boundary was found to consist of two regions: an area with pairs of partial dislocations and an area with groups of odd numbered partial dislocations (multiple-partial-structure). Eight kinds of multiple-partial-structures were found in the fabricated grain boundary. The Burgers vectors of each partial dislocation in the grain boundary could be distinguished by dark-field imaging, and thus the arrangement of partial dislocations in the multiple-partial-structures were determined. It was concluded that a slight twist component of the boundary was the origin of the characteristic multiple-partial-structures.

Partial Dislocation Configurations in a Low-Angle Boundary in α-Al2O3. E.Tochigi, N.Shibata, A.Nakamura, T.Yamamoto, Y.Ikuhara: Acta Materialia, 2008, 56[9], 2015-21