Mobility of arrays of dissociated and superlattice dislocations in an internally stressed solid

A study is made of the mobility of planar arrays of dislocations of Burgers vector b that are either separated into their component partials or are of the superlattice type and are contained in an internally stressed solid, the stress being generated by a preexisting coplanar obstacle dislocation of Burgers vector mb. The aim here is to estimate the effect of the internal stress and the fault energy on the separation between the components of the first discrete dislocation since the latter plays an important part in a wide range of physical phenomena. All the mobile complete dislocations except the leader are either smeared into a continuous distribution or are replaced by a superdislocation of appropriate Burgers vector. These two approaches, which lead to lower and upper bounds for the separation distance, are shown to give fairly close results for small m. Journal of Applied Physics is copyrighted by The American Institute of Physics.