On slip band growth in neutron-irradiated copper single crystals

A transmission electron microscopy (TEM) study of the dislocation structure in slip bands at the Lüders band front in neutron-irradiated copper (Cu) single crystals reveals bands in various stages of development. This permits to specify the dislocation processes in particular for termination of slip band growth in the yield region. The important processes occurring during slip band growth are obstacle destruction by moving dislocations, formation of dynamic pile-ups, frequency of microscopic cross-slip and climb processes, formation of multipoles and of clusters of heavily jogged edge dipoles, which ultimately stop the local deformation in the cleared slip band channel. The formation of a dislocation group in the stress gradient within the Lüders band region is considered and it is shown that the group behaves like a single dislocation placed in the “center of gravity” of the quasi-stationary distribution which is the same as in the static case.