Width and density of persistent slip bands as a consequence of deformation mesostructure

Abstract
A system of persistent slip bands (PSBs) in a steady state cyclically deformed crystal is treated as a dynamic structure developed by a self-organization process. The wave length of the dislocation structure formed in the bands represents the intrinsic length scale controlling the average width and density of PSBs. The model is described by the equation of motion for glide dislocations and the equations of elasto-plastic continuum. The basic assumption is that the glide properties of dislocations in all active slip planes of the PSB lamellae of localized shear are the same. The evaluated ratio of the wave length of the dislocation structure in PSBs to the average width of PSBs is compared with the measured values. The predicted proportionality of the density of PSBs to the applied plastic strain amplitude is in agreement with the observation. Dedicated to Prof. Dipl.-Ing. Dr. techn. F. Ziegler on the occasion of his 60th birthday.