The Dislocation Image Force in Cubic Polycrystals

The image force on a screw dislocation in an anisotropic cubic polycrystal is examined as a function of elastic anisotropy and Burgers vector. For iron it is shown that the screw glide dislocation is always repelled from a grain boundary but for copper there can be either an attraction or repulsion depending on the misorientation across the grain boundary.