The mobility of dislocation groups

A computer calculation is described in which a group of mobile edge dislocations is driven by an applied stress towards a similar group of dislocations in the form of a pile-up on a parallel slip plane. It is found that the leading member of the mobile group is able to pass the pile-up at a distance normal to the slip plane which is only about one-third of that at which a single dislocation could do the same. Some consequences of this result to the theory of work-hardening are discussed.