It was recalled that persistent slip bands were surface microstructural features that commonly arose when a polycrystalline metal experienced fatigue. As dislocations were carriers of plastic strain, and persistent slip bands were essentially strain-localisation regions, the evolution of dislocations was expected to be pivotal in determining the fatigue behaviour. The role of dislocations was investigated here by considering their kinematic activities (generation, annihilation, trapping) as incorporated into crystal plasticity theory. The results were consistent with reported experimental observations; indicating that persistent slip bands formation was due to the accumulation of edge dislocation dipoles caused by trapping events.

The Role of Dislocations in Cyclically Deformed Metal Polycrystals. K.S.Cheong: Current Applied Physics, 2008, 8[3-4], 436-9