Effect of piled-up dislocations on strain induced boundary migration (SIBM) in deformed aluminum bicrystals with originally Σ3 twin boundary

Using aluminum bicrystal specimens with Sigma3 twin boundary at the initial orientation, deformation and recrystallization experiments were performed in order to clarify the contribution of piled-up dislocations at the grain boundary (GB) to the occurrence of the strain induced grain boundary migration (SIBM). In the tensile deformation of the specimen along the < 011 > axis to a strain of 20%, an inhomogeneously deformed structure was developed along the GB. After annealing, the SIBM was observed along the original GB. These screw dislocations passed easily through the GB because of the special orientational and geometric conditions, whose motion acted as the stress relief mechanism against the imposed strain. It was found that the SIBM was caused by the edge component of dislocations piled up against the GB. (C) 2001 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.