Dislocation-based description of the sliding of a free-surface emerging grain boundary

The sliding phenomenon of a high-angle tilt boundary containing a disclination dipole emerging at the free-surface of a thin film deposited on a semi-infinite substrate is studied theoretically from a static point of view in the framework of a dislocation-based description. The formation from the surface of a dislocation in the boundary is investigated, and its different equilibrium positions are determined in the stress field of the disclination dipole. It is found that the formation of the dislocation in the stress field of the disclination is only possible for an inclined dipole with respect to the normal of the free-surface. Finally, the effects of the inclination angle and strength of the grain boundary disclination dipole on the stable and metastable equilibrium positions of the dislocation are analyzed.