Acta Materialia 51 (2003) 3821–3830 www.actamat-journals.com Lattice rotations of individual bulk grains Part I: 3D X-ray characterization H.F. Poulsen a,* , L. Margulies a,b , S. Schmidt a , G. Winther a a Center for Fundamental Research: Metal Structures in Four Dimensions, Risø National Lab., DK-4000, Roskilde, Denmark b European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble Cedex, France Received 19 February 2003; received in revised form 6 April 2003; accepted 8 April 2003 Abstract Three-dimensional X-ray diffraction has been applied to characterise the plastic deformation of individual grains deeply embedded in a 99.6% pure aluminium specimen. The specimen is 4 mm thick with an average grain size of 75 μm. The average lattice rotation for each grain as well as the degree of internal orientation spread within the grain is measured in-situ during 6% elongation. The rotation paths for 95 grains with nearly random initial orientations are reported. The quality of this data set is sufficient to make distinctions between plasticity models. The rotation paths exhibit a clear dependence on the initial orientation, while the influence of grain interaction is relatively small. All grains deform plastically. Averaged over grains and reflections the rotation of the tensile axis and the FWHM of the internal spread is 2.0 and 0.8°, respectively, at 6% strain.  2003 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved. Keywords: Plastic deformation; X-ray diffraction; Aluminium; Texture; Synchrotron radiation 1. Introduction Polycrystal plasticity models describing texture evolution are based on the prediction of active slip systems in individual grains and calculation of the resulting lattice orientation [1–6]. The field has been impeded by lack of suitable experimental data on the dynamics of individual grains. Studies of lattice rotations within surface or near-surface * Corresponding author. Tel.: +45 4677 5739; fax: +45 4677 5758. E-mail address: henning.friis.poulsen@risoe.dk (H.F. Poulsen). 1359-6454/03/$30.00  2003 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved. doi:10.1016/S1359-6454(03)00206-4 grains do exist (e.g. [7]), but the dynamics of such may not be representative of bulk behaviour. In order to mimic bulk conditions a set of experiments were performed by Barrett and Leven- son [8] and later by Panchanadeeswaran, Doherty and co-workers [9–11]. In these studies, two metal surfaces were pressed tightly together during deformation and characterisation was performed by surface probes on these two “interior” surfaces before and after deformation. While demonstrating that individual grains do not behave as average grains, it is unclear to what extent the interface influenced the results. Recently, we have demonstrated the feasibility of monitoring the lattice rotation of deeply embed-