Abstract
The low-angle grain boundaries and their intersections in melt-textured YBa2Cu3O7-x have been characterized by TEM. Grain boundaries are found to contain both tilt and twist components and consist of dislocation arrays, These boundaries are also observed to interact and at the regions of interaction the ab-planes alignment of the grains is maintained by varying the values and directions of the twist and tilt angles, and is also accompanied by changes in the grain boundary plane. These changes seem to influence the effectiveness of pinning of grain boundary dislocations. The dislocation structure of these grain boundaries is discussed in connection with their possible coupling properties. Based on this analysis, most of these boundaries are found to be strongly coupled, but short pieces of these boundaries can be weakly coupled. However, the influence of these pieces on the J(c) of the total boundary is negligible.