Formation and evolution of persistent slip bands in metals

The formation and evolution of persistent slip bands (PSB) in metals under fatigue is investigated. The metal is considered as an active medium of the activator-inhibitor type where the immobile dislocations play the role of the activator while the mobile ones that of the inhibitor. Persistent slip band formation is regarded as a result of spontaneous formation and evoluti on of localized dissipative structures in the form of solitary static regio ns. Analytical results for the wavelength of the pattern and the dislocatio n densities are obtained far from the bifurcation point, It is shown that t he wavelength of the PSB pattern lies between two extreme values defined by the material properties and the excitation level. The obtained results are discussed and compared with available experimental observations, (C) 2000 Elsevier Science Ltd. All rights reserved.