Influence of Jog Concentration on the Conservative Motion of Dislocations in Copper

Abstract

In an annealed crystal of low dislocation density, the critical resolved shear stress necessary to move circular prismatic edge-dislocation loops along their glide cylinders was compared to the range of stresses within which various segments of the three-dimensional network began to move. Etch-pit observations showed that the first segments of the network moved at 2 g/mm2 but that only 60% had moved when the maximum resolved shear stress had reached 38 g/mm2. Circular prismatic loops, which because of their shape have a high jog concentration, were found to move at a critical resolved shear stress greater than 50 g/mm2. It was suggested that jog concentration should be expected to vary from one segment to another of the three-dimensional network in an annealed crystal, and that this is probably one important reason for the widely different stresses at which individual segments begin to move.