Junction reaction hardening by dislocation loops

Abstract The movement of a flexible dislocation line through a random array of circular dislocation loops has been studied, using a digital computer, on the basis of the line tension approximation. The dislocation moves on a {111} plane of a face-centred cubic crystal and interacts with {110} prismatic loops by the formation of short junction reactions at the points of intersection. The critical stress required to propagate the dislocation through the loops is μb/1·75L, where L is the average spacing of the reactive loops cutting the glide plane (one-third of all the loops are reactive). This result is independent of the radius and sense of the loops and the edge-screw character of the glide dislocation. It is slightly increased when the loops are distributed more uniformly, in disagreement with the factor two reduction predicted by Westmacott et al: (1966). The present estimate of loop hardening is comparable with the tetragonal distortion model of Fleischer (1962), and is in agreement with the measured ...