A theory for the dynamics of edge dislocation dipoles was presented which took account of dipole formation via the mutual trapping of mobile edge dislocations of opposite sign, of glide-induced dipole changes leading to the formation of narrower (stronger) dipoles, of glide-induced dipole decomposition and of glide-induced dipole annihilation. The approximate analytical results for the corresponding reaction cross-sections were in good agreement with previous numerical results. The steady-state distribution of dipole widths was calculated from a kinetic equation. The average dipole strength and the cyclic anelastic strain which was accommodated by the reversible breathing of dipoles were derived, and compared with experiment. The results provided the starting point for a theory of dislocation patterning during fatigue (matrix and persistent slip-band structure). However, two modifications of the theory were required in order to explain the formation of highly ordered persistent slip-bands which exhibited a large amount of irreversible plastic strain (dynamic equilibrium between dislocation generation and annihilation). One modification was that a stochastic approach was used to account for the stress and strain-rate fluctuations which were caused by long-range dislocation interactions. The other modification was that mutual stabilization of dipoles in the dislocation-rich walls was expressed in terms of an exhaustion factor for dipole decomposition.

The Dynamics of Dislocation Dipoles during Single Glide. P.Hahner: Scripta Materialia, 1996, 34[3], 435-41