Measurement of the components of plastic displacement gradients in three dimensions

Søren Fæster Nielsen, F. Beckmann, R.B. Godiksen, K. Haldrup, H.F. Poulsen, J.A. Wert

    Research output: Chapter in Book/Report/Conference proceedingArticle in proceedingsResearchpeer-review


    A method for non-destructive characterization of plastic deformation in bulk materials is presented. The method is based on X-ray absorption microtomography investigations using X-rays from a synchrotron source. The method can be applied to materials that contain marker particles, which have an atomic number significantly different from that of the matrix material. Data were acquired at the dedicated microtomography instrument at beamline BW2 at HASYLAB / DESY, for a cylindrical aluminium sample containing W particles with an average particle diameter of 7 mum. The minimum detectable size of the maker particles is 1-2 mum with the present spatial resolution at HASYLAB. The position (x,y,z) of all the detected marker particles within 1 mm(3) was determined as function of strain. The sample was deformed in stepwise compression along the axis of the cylinder. A tomographic scan was performed after each deformation step. After a series of image analysis steps to identify the centre of mass of individual particles and alignment of the successive tomographic reconstructions, the displacements of individual particles could be tracked as a function of external strain. The particle displacements are then used to identify local displacement gradient components, from which the local 3D plastic strain tensor can be determined. This allows us to map the strain components as a function of location inside a deforming metallic solid.
    Original languageEnglish
    Title of host publicationDevelopments in X-ray tomography 4
    EditorsU. Bonse
    Place of PublicationBellingham, WA
    PublisherThe International Society for Optical Engineering
    Publication date2004
    ISBN (Print)0-8194-5473-7
    Publication statusPublished - 2004
    Event4th Conference on Developments in X-Ray Tomography - Denver, United States
    Duration: 4 Aug 20046 Aug 2004
    Conference number: 4


    Conference4th Conference on Developments in X-Ray Tomography
    Country/TerritoryUnited States
    SeriesProceedings of SPIE - The International Society for Optical Engineering


    • synchrotron radiation
    • plastic deformation
    • X-ray tomography
    • discrete tomography
    • image analysis


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