Determining grain resolved stresses in polycrystalline materials using three-dimensional X-ray diffraction

Jette Oddershede, Søren Schmidt, Henning Friis Poulsen, Henning Osholm Sørensen, Jonathan Wright, Walter Reimers

    Research output: Contribution to journalJournal articleResearchpeer-review

    Abstract

    An algorithm is presented for characterization of the grain resolved (type II) stress states in a polycrystalline sample based on monochromatic X-ray diffraction data. The algorithm is a robust 12-parameter-per-grain fit of the centre-of-mass grain positions, orientations and stress tensors including error estimation and outlier rejection. The algorithm is validated by simulations and by two experiments on interstitial free steel. In the first experiment, using only a far-field detector and a rotation range of 2 × 110°, 96 grains in one layer were monitored during elastic loading and unloading. Very consistent results were obtained, with mean resolutions for each grain of approximately 10 µm in position, 0.05° in orientation, and 8, 20 and 13 × 10-5 in the axial, normal and shear components of the strain, respectively. The corresponding mean deviations in stress are 30, 50 and 15 MPa in the axial, normal and shear components, respectively, though some grains may have larger errors. In the second experiment, where a near-field detector was added, ~ 2000 grains were characterized with a positional accuracy of 3 µm.
    Original languageEnglish
    JournalJournal of Applied Crystallography
    Volume43
    Issue number3
    Pages (from-to)539-549
    ISSN0021-8898
    DOIs
    Publication statusPublished - 2010

    Keywords

    • Materials characterization and modelling
    • Materials and energy storage

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