Some Properties of the Disclination Structure of Grain Boundaries

The interaction between a simple tilt boundary made of wedge disclination dipoles and a single edge dislocation is studied. It is found that in general edge dislocations can be generated or absorbed at the wedge disclination dipoles. The dilatation field of such a boundary is calculated and from which the interaction with impurity atoms which cause dilatational distortions of the lattice is studied. The resulting periodic distribution of impurity atoms along the boundary is suggested to play a role in intergranular embrittlement and grain boundary sliding.