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 degrees 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 degrees 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 degrees tilt boundary was clearly different from that in the 0.4 degrees tilt boundary, which suggests that the strain fields of neighbouring dislocations interact when the separation distance between dislocations is shorter than a critical value.