It was noted that a straight dislocation which was parallel to the interface of two perfectly bonded dissimilar linear elastic half-spaces experienced a Peach-Koehler image force that tended to move the dislocation towards or away from the interface. The general rule was that the dislocation was repelled from the interface when it resided in the elastically softer of the two half-spaces, and was attracted to the interface when it resided in the stiffer half-space. It was proved that this rule held exactly for so-called proportional anisotropic bi-metals. That is, for two perfectly joined half-spaces for which Cijkl(2) = λCijkl(1), where the constant, λ, was positive. Thus, for a dislocation in medium (1), repulsion occurred for λ > 1 and attraction occurred for λ < 1. This rule did not always hold since, for a pure edge dislocation in a bi-metal that comprised two perfectly bonded dissimilar isotropic half-spaces, the dislocation was either attracted to the interface from one side and repelled from the interface from the other side (the usual case), or the dislocation was repelled from the interface no matter which half-space was dislocated. The possibility of attraction from both sides (mutual attraction) did not occur for a pure edge dislocation. This work showed that, if the dislocation had both edge and screw components, then mutual attraction was possible in an isotropic bi-metal.

Mutual Attraction of a Dislocation to a Bimetallic Interface and a Theorem on Proportional Anisotropic Bimetals. D.M.Barnett, J.Lothe: International Journal of Solids and Structures, 1995, 32[3-4], 291-301