Improved grain mapping by laboratory X-ray diffraction contrast tomography

H. Fang*, D. Juul Jensen, Y. Zhang

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

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Abstract

Laboratory diffraction contrast tomography (LabDCT) is a novel technique for non-destructive imaging of the grain structure within polycrystalline samples. To further broaden the use of this technique to a wider range of materials, both the spatial resolution and detection limit achieved in the commonly used Laue focusing geometry have to be improved. In this work, the possibility of improving both grain indexing and shape reconstruction was investigated by increasing the sample-to- detector distance to facilitate geometrical magnification of diffraction spots in the LabDCT projections. LabDCT grain reconstructions of a fully recrystallized iron sample, obtained in the conventional Laue focusing geometry and in a magnified geometry, are compared to one characterized by synchrotron X-ray diffraction contrast tomography, with the latter serving as the ground truth. It is shown that grain indexing can be significantly improved in the magnified geometry. It is also found that the magnified geometry improves the spatial resolution and the accuracy of the reconstructed grain shapes. The improvement is shown to be more evident for grains smaller than 40 mm than for larger grains. The underlying reasons are clarified by comparing spot features for different LabDCT datasets using a forward simulation tool.
Original languageEnglish
JournalI U Cr J
Volume8
Pages (from-to)559-573
ISSN2052-2525
DOIs
Publication statusPublished - 2021

Keywords

  • 3D grain mapping
  • Diffraction contrast tomography
  • X-ray diffraction
  • Spatial resolution
  • Magnified geometries
  • Detection limits

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