Quantitative assessment of the driving force for twin formation utilizing Nye tensor dislocation density mapping

Transmission electron microscopy was coupled with precession electron diffraction methods to determine the role of local defect distributions in the formation and growth behavior of twin nuclei. Three distinct cases were observed that are indicative of three separate formation mechanisms, two as the result of annealing and the third as a result of deformation. While all of the observed cases are consistent with the proposed mechanisms for twin formation found in literature, this study marks the first experimental evidence to support all three mechanisms occurring simultaneously in the same microstructure. (C) 2016 Elsevier B.V. All rights reserved.