Materials Science and Engineering A 387–389 (2004) 84–88 Simultaneous measurement of the strain tensor of 10 individual grains embedded in an Al tensile sample René V. Martins a , Lawrence Margulies a,b , Søren Schmidt a , Henning F. Poulsen a,∗ , Torben Leffers a a Risø National Laboratory, Materials Research Department, DK-4000 Roskilde, Denmark b European Synchrotron Radiation Facility, B.P. 220, F-38043 Grenoble Cedex, France Received 26 August 2003; received in revised form 13 February 2004 Abstract First results are presented on the simultaneous observation of the elastic strain tensor as a function of load of 10 individual grains, deeply embedded in the bulk of a polycrystalline Al tensile sample. The experimental technique is based on the use of focused high energy synchrotron radiation in transmission geometry. After each load step diffraction patterns are collected with a large-area X-ray detector system for a series of different angular and lateral sample positions. An automated indexing routine was used to assign sets of diffraction spots to individual grains. The strain tensor components as well as the individual grain position within the sample were then fitted from the diffraction spot positions. A maximum tensile load of 48 MPa was applied. Deviations in strain of up to 600 × 10 -6 are observed between respective strain components of individual grains. © 2004 Elsevier B.V. All rights reserved. Keywords: Stress–strain relationship measurements; X-ray diffraction; Synchrotron radiation 1. Introduction From the development of the first plasticity model some 70 years ago [1], until nowadays several models have been proposed to predict aspects of plastic deformation such as texture and flow-stress development in polycrystalline metal aggregates. These models can be grouped accord- ing to the assumptions and simplifications concerning the grain–grain interaction. The models range from so-called “one-site” models to “n-site” models. An inherent property of the “one-site” models (e.g. [1–5]) is that grains with the same orientation behave identically. Experimental data for the verification of these models is usually obtained from techniques, which measure the average behavior of grain populations with specific lattice orientations. In contrast, “n-site” models (e.g. [6]), predict a different behavior for grains having the same orientation. A verification of these models requires therefore experimental data obtained from ∗ Corresponding author. Tel.: +45-4677-5739; fax: +45-4677-5758. E-mail address: henning.friis.poulsen@risoe.dk (H.F. Poulsen). individual grains. These grains have to be deeply embed- ded in the sample in order to be representative for the bulk material. The lack of detailed experimental data did not permit to give explicit answers to important issues such as the influence of the grain microstructure and the influence of neighboring grains on the plastic deformation behavior. Previous experimental results addressing the aspect of the individual orientation change of a large number of indi- vidual grains subjected to plastic deformation [7], showed that the now existing “one-site” models are not able to pre- dict accurately the lattice rotation during the deformation process. A first feasibility study to measure the elastic strain of one single embedded grain was published by Margulies et al. [8]. The technique described there was modified for the si- multaneous determination of the elastic strain tensor in a larger set of grains which is intended as a further step in the direction of providing a large experimental data set for a more detailed understanding of the stress–strain relationship of individual grains and for comparison to “n-site” modeling results. 0921-5093/$ – see front matter © 2004 Elsevier B.V. All rights reserved. doi:10.1016/j.msea.2004.02.069