The atomic structure of a Σ = 3, [110]/{112} grain boundary, in a yttria-stabilized cubic zirconia bicrystal, was investigated by means of high-resolution transmission electron microscopy. It was found that the grain boundary migrated so as to form periodic facets, although the bicrystal was initially joined so as to have a symmetrical {112} boundary plane. The faceted boundary planes were {111}/{115}. The structure of the {111}/{115} grain boundary comprised an alternating array of 2 types of structural unit: {112} and {111}. High-resolution transmission electron microscopic observations, combined with lattice statics calculations, confirmed that both crystals were relatively shifted by (a/4)[110] along the rotation axis so as to form a stable grain-boundary structure. Weak-beam dark-field images revealed that there was a periodic array of dislocations along the grain boundary. The grain boundary dislocations were suggested to have been introduced by a slight misorientation from the perfect Σ = 3 orientation. The observation that the periodicity of the facets corresponded to that of the grain-boundary dislocations suggested that the introduction of the grain-boundary dislocations was closely related to the periodicity of the facets. An atomic flipping model was proposed to explain the facet growth from the initial Σ = 3 {112} grain boundary.

Grain-Boundary Faceting at a Σ = 3, [110]/{112} Grain Boundary in a Cubic Zirconia Bicrystal. N.Shibata, F.Oba, T.Yamamoto, T.Sakuma, Y.Ikuhara: Philosophical Magazine, 2003, 83[19], 2221-46