The elastic energy of a rhombus-shaped dislocation loop

Abstract

Abstract The elastic strain energy of a rhombus-shaped dislocation loop is calculated for an arbitrary rotation about the minor or major diagonal axis. For loops less than about one micron in size and constrained to move on the glide prism a shallow minimum in the energy exists displaced from the pure edge loop orientation. The depth of the minimum and its displacement from the pure edge orientation increase as the loop size decreases. The results provide an explanation for the observation by Makin and Hudson (1963) of such loops lying in {012} planes rather than in the {011} plane normal to the Burgers vector. The importance of the work done by the dislocation core tractions is emphasized and in particular its dependence on the method adopted for formally generating the dislocation loop. The misorientation effect is enhanced if the loop becomes extended into a pair of partials with a ribbon of stacking fault. An estimate of the core energy on the basis of an extended Peierls model does not preclude the e...