Dislocation structures and strain fields in [111] low-angle tilt grain boundaries in zirconia bicrystals

Structures of <111> low-angle tilt grain boundaries in yttria-stabilized cubic zirconia bicrystals were characterized by conventional transmission electron microscopy, high-resolution transmission electron microscopy and high-angle annular dark-field scanning transmission electron microscopy. It is found that the 0.4 and 4.0° tilt grain boundaries are composed of periodic arrays of edge dislocations with Burgers vectors. The experimentally estimated strain field of each dislocation in the 0.4° tilt boundary was in good agreement with the theoretically predicted strain field from the Peierls-Nabarro model. On the other hand, the estimated strain field of each dislocation in the 4.0° tilt boundary was clearly different from that in the 0.4° tilt boundary, which suggests that the strain fields of neighbouring dislocations interact when the separation distance between dislocations is shorter than a critical value.