Grain-resolved elastic strains in deformed copper measured by three-dimensional X-ray diffraction Jette Oddershede a, ⁎ , Søren Schmidt a , Henning Friis Poulsen a , Lawrence Margulies a, 1 , Jonathan Wright b , Marcin Moscicki c , Walter Reimers d , Grethe Winther a a Center for Fundamental Research: Metal Structures in Four Dimensions, Materials Research Division, Risø DTU, Frederiksborgvej 399, DK-4000 Roskilde, Denmark b European Synchrotron Research Facility, 38043 Grenoble, France c Max-Planck-Institut für Eisenforschung GmbH, Max-Planck-Str. 1, 40237 Düsseldorf, Germany d Technische Universität Berlin, Sekr. BH18, Ernst-Reuter-Platz 1, 10587 Berlin, Germany ARTICLE DATA ABSTRACT Article history: Received 16 November 2010 Received in revised form 7 April 2011 Accepted 27 April 2011 This X-ray diffraction study reports the grain-resolved elastic strains in about 1000 randomly oriented grains embedded in a polycrystalline copper sample. Diffraction data were collected in situ in the undeformed state and at a plastic strain of 1.5% while the sample was under tensile load. For each grain the centre-of-mass position was determined with an accuracy of 10 μm, the volume with a relative error of 20%, the orientation to 0.05° and the axial strain to 10 - 4 . The elastic strain along the tensile direction exhibited a grain orientation dependence with grains within 20° of <100> carrying the largest strain. While the width of the strain distribution for all grains did not change upon plastic loading, the grain-resolved data show a significant widening of the distribution evaluated for small subsets of initially elastically similar grains. This widening appears independent of the grain orientation. © 2011 Elsevier Inc. All rights reserved. Keywords: Synchrotron X-ray diffraction Strain measurement Bulk deformation Crystal plasticity Orientation relationships 1. Introduction Polycrystal plasticity models are widely used to predict both the evolution of deformation textures and the resulting mechanical properties, for example mechanical anisotropy. Historically, polycrystal plasticity modelling has relied on assumptions about the local stress/strain conditions at the level of individual grains, spanning from enforcement of the same strain on all grains in the Taylor [1] and Bishop-Hill [2] models, over consideration of the interaction between a grain and a homogenous medium with the average properties of all the other grains (self-consistent models, e.g. [3]), to detailed modelling of the interaction between neighbouring grains in models based on the finite element method (e.g. [4]) or Fourier transformations [5]. The verification and improvement of models have been impeded by the lack of experimental data on both the plastic deformation (plastic strain as well as the associated lattice rotation) and the elastic strains at the grain scale. Recently, measurements using neutrons or X-rays have progressed from probing bulk textures to providing the lattice rotations of a large number of individual grains deeply embedded in the bulk of the sample by means of the three-dimensional X-ray diffraction (3DXRD) technique [6–9]. Diffraction of neutrons [10] or X-rays [11,12] can also be used to measure elastic strains. Due to limited spatial resolution of MATERIALS CHARACTERIZATION 62 (2011) 651 – 660 ⁎ Corresponding author. Tel.: +45 4677 5817; fax: +45 4677 5758. E-mail address: jeto@risoe.dtu.dk (J. Oddershede). 1 Present address: Brookhaven National Laboratory, Blg. 703, Upton, NY 11973, USA. 1044-5803/$ – see front matter © 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.matchar.2011.04.020 available at www.sciencedirect.com www.elsevier.com/locate/matchar