Theory of solitary plastic waves

The paper deals with the dislocation dynamics of coherently propagating modes of plastic shear (Lüders bands) in single crystals oriented for single slip, in terms of a generalized Fisher-Kolmogorov equation. The role of (1) cross-slip and (2) non-axial stresses as propagation mechnisms is investigated, and the problem of propagation velocity selection is addressed. The phenomenon of slip band clustering which was observed in sufficiently thick tensile specimens is traced back to a propagative instability owing to non-axial stresses.