Mechanically driven annealing twinning induced by cyclic deformation in nanocrystalline Cu

This investigation addresses a new finding on the formation of twins similar to 100-500 nm thick in nanocrystalline Cu during cyclic deformation. This twin formation is related to the emission of Shockley partials from extensively migrating grain boundaries. Given the similarities of formation mechanism and morphology to those observed during annealing, these twins were termed mechanically driven annealing twins. Moreover, the dynamic interactions between dislocations and twin boundaries were also explored, as these interactions may hinder the propagation of twins. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.