The model of PSB formation

The evolution of persistent slip bands (PSBs) is treated as a consequence of an instability transition accompanied by a process of self-organization of dislocations stored in the deformed metal crystal. The proposed qualitative model is analysed by the perturbation method. The first order perturbation analysis of the model at the state of zero hardening, which simulates a disintegrating dislocation vein structure, predicts an appearance of shear bands of localized slip. The second order perturbation indicates that within the bands of localized slip a new dislocation structure of the ladder type may appear. The thickness of the PSBs is estimated using minimization of the elastic strain energy of the internal stresses caused by the walls of the ladder structure.