Strain localization in cyclic deformation of copper single crystals

Abstract

Abstract The localization of plastic strain into macroscopic groups of persistent slip bands has been determined on copper single crystals strain-cycled into saturation. The macroscopic bands traverse the whole cross section and undergo complete reversibility of plastic strain with load reversibility. Although overall, surface slip steps form in proportion to the applied plastic strain, individual steps are not always completely reversed, leading to the rapid formation of a notch-peak topography within the bands. The dislocation structure of the persistent slip bands was determined, permitting a critical assessment of the various mechanisms proposed for saturation in low-strain cyclic deformation. Using existing ideas, an adequate model of saturation is based upon the cooperative movement of primary links between the persistent slip-band walls, but impeded in their motion by point-defect clusters and small dislocation debris.