Published online by Cambridge University Press: 10 February 2011
When a grain boundary is terminated by a free surface, its behavior may be significantly different than for the same boundary either in an infinite bicrystal, or terminated by triple junctions. In this paper we describe some phenomena related to the free-surface interactions of interfacial dislocations, in thin films. We show that surface relaxation stresses can exert a powerful destabilizing influence upon the dislocation structure of many grain boundaries, and that they can only be made stable if a large lattice friction stress, or other pinning force, resists the motion of the dislocations. Finally, we will show that the only intrinsically stable grain boundary in a thin film is a tilt boundary with its rotation axis parallel to the normal of the film.