In situ synchrotron X-ray topography study of the generation of lattice dislocations in aluminium by migrating grain boundaries

Abstract

The generation of lattice dislocations by migrating grain boundaries has been studied in aluminium, both in situ and in real time, by synchrotron white-beam X-ray topography (SWBXT). It has been established that matrix screw dislocations are left by, and trailed behind, moving grain boundaries and that these defects are incorporated in a dislocation network produced by reaction with dislocations originating from the grain nucleus. As opposed to Gleiter's findings in InP and InAs, the density of matrix dislocations left by a moving grain boundary in aluminium does not depend on its migration rate. The production of these defects seems better associated with stresses acting in the grain boundary plane during the recrystallization process, which leads to a proposal for a new dislocation generation mechanism.