Nonlinearity and localization of plastic deformation in Zn single crystals with forest dislocation

The influence of the dislocation forest on the work hardening curves during basal slip as well as the structure of the local shear bands in Zn single crystals have been investigated. The forest dislocation were introduced into the single crystals in the systems ((2) over bar 112) [2<(11)over bar>3] and (2<(11)over bar>2) [2<(11)over bar>3]. The density of the forest dislocation was varied from 10(3) to 10(7) cm(-2). It was established that the increase of the forest dislocation density led to essential changes in the work hardening curves and promoted the formation of large shear bands in the basal and pyramidal slip systems. A transformation of the forest dislocations into slipping basal ones is proposed to account for the observed effects. (C) 1998 Elsevier Science S.A. All rights reserved.