Bicrystals which contained [00▪1] symmetrical tilt grain boundaries were fabricated to investigate atomic structures at their grain-boundary cores. Σ7 and Σ21 boundaries studied here had crystallographically equivalent grain-boundary planes of although they had different Σ values. Grain-boundary structures were studied by high-resolution transmission electron microscopy and static lattice calculations based upon ionic potentials. High-resolution transmission electron microscopy observations showed that the Σ7 and Σ21 boundaries exhibited asymmetric core structures with respect to their grain-boundary planes. From static lattice calculations, it was found that these two grain boundaries had similar rigid-body shifts normal to the tilt axis and also contain open spaces at their core. The similarity of their core structures indicated that characteristics of grain-boundary cores strongly depended upon features of grain-boundary planes.

High-Resolution Transmission Electron Microscopy and Computational Analyses of Atomic Structures of [0001] Symmetric Tilt Grain Boundaries of Al2O3 with Equivalent Grain-Boundary Planes. K.Matsunaga, H.Nishimura, T.Saito, T.Yamamoto, Y.Ikuhara: Philosophical Magazine, 2003, 83[36], 4071-82