Bowing out of a dislocation from wall of persistent slip bands (PSB)

Edge dislocation segments bowing out of dislocation walls of persistent slip bands (PSBs) during cycling are experimentally well documented. Instead of dealing with the problem in its complexity a simplified computer simulation of this process is presented. The bowing out segment interacts with the wall of the PSB. The walls are represented by the elastic field of a cluster of edge dipolar loops. Mutual interactions between the loops in the cluster and an interaction between the loop cluster and the bowing out dislocation segments are incorporated in the simulation procedure. The dislocation segments deposited at the walls are trapped in the elastic potential valleys produced by the dipole loops. Our aim is to determine the local shear stress needed to bow out fully the edge dislocation segment from the PSB wall. The obtained result is in reasonable agreement with the local shear stress at the wall deduced from measurements.