3D grain reconstruction from laboratory diffraction contrast tomography

A method for reconstructing the three-dimensional grain structure from data collected with a recently introduced laboratory-based X-ray diffraction contrast tomography system is presented. Diffraction contrast patterns are recorded in Laue-focusing geometry. The diffraction geometry exposes shape information within recorded diffraction spots. In order to yield the three-dimensional crystallographic microstructure, diffraction spots are extracted and fed into a reconstruction scheme. The scheme successively traverses and refines solution space until a reasonable reconstruction is reached. This unique reconstruction approach produces results efficiently and fast for well suited samples.

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Three-dimensional grain structure of sintered bulk strontium titanate from X-ray diffraction contrast tomography

Scripta Materialia ◽

10.1016/j.scriptamat.2011.08.005 ◽

2012 ◽

Vol 66 (1) ◽

pp. 1-4 ◽

Cited By ~ 34

Author(s):

M. Syha ◽

W. Rheinheimer ◽

M. Bäurer ◽

E.M. Lauridsen ◽

W. Ludwig ◽

...

Keyword(s):

Strontium Titanate ◽

Three Dimensional ◽

Grain Structure ◽

X Ray Diffraction ◽

X Ray ◽

Diffraction Contrast

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X-ray diffraction contrast tomography: a novel technique for three-dimensional grain mapping of polycrystals. II. The combined case

Journal of Applied Crystallography ◽

10.1107/s0021889808001726 ◽

2008 ◽

Vol 41 (2) ◽

pp. 310-318 ◽

Cited By ~ 113

Author(s):

Greg Johnson ◽

Andrew King ◽

Marcelo Goncalves Honnicke ◽

J. Marrow ◽

Wolfgang Ludwig

Keyword(s):

Electron Backscatter Diffraction ◽

Three Dimensional ◽

Real Data ◽

X Ray Diffraction ◽

Data Set ◽

Transmitted Beam ◽

X Ray ◽

Diffraction Contrast ◽

Simultaneous Acquisition ◽

Backscatter Diffraction

By simultaneous acquisition of the transmitted and the diffracted beams, the applicability of the previously introduced diffraction contrast tomography technique [Ludwig, Schmidt, Lauridsen & Poulsen (2008).J. Appl. Cryst.41, 302–309] can be extended to the case of undeformed polycrystalline samples containing more than 100 grains per cross section. The grains are still imaged using the occasionally occurring diffraction contribution to the X-ray attenuation coefficient, which can be observed as a reduction in the intensity of the transmitted beam when a grain fulfils the diffraction condition. Automating the segmentation of the extinction spot images is possible with the additional diffracted beam information, even in the presence of significant spot overlap. By pairing the corresponding direct (`extinction') and diffracted beam spots a robust sorting and indexing approach has been implemented. The analysis procedure is illustrated on a real data set and the result is validated by comparison with a two-dimensional grain map obtained by electron backscatter diffraction.

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Three-dimensional α colony characterization and prior-β grain reconstruction of a lamellar Ti–6Al–4V specimen using near-field high-energy X-ray diffraction microscopy

Journal of Applied Crystallography ◽

10.1107/s1600576715011139 ◽

2015 ◽

Vol 48 (4) ◽

pp. 1165-1171 ◽

Cited By ~ 9

Author(s):

E. Wielewski ◽

D. B. Menasche ◽

P. G. Callahan ◽

R. M. Suter

Keyword(s):

Near Field ◽

Three Dimensional ◽

High Energy ◽

Grain Structure ◽

X Ray Diffraction ◽

Orientation Field ◽

X Ray ◽

Hexagonal Close Packed ◽

Flood Fill ◽

Diffraction Microscopy

Near-field high-energy X-ray diffraction microscopy has been used to characterize the three-dimensional (3-D) crystallographic orientation field of the hexagonal close-packed α phase in a bulk Ti–6Al–4V specimen with a lamellar (β-annealed) microstructure. These data have been segmented using a 3-D misorientation-based grain finding algorithm, providing unprecedented information about the complex 3-D morphologies and spatial misorientation distributions of the transformed α lamella colonies. A 3-D Burgers orientation relationship-based flood-fill algorithm has been implemented to reconstruct the morphologies and crystallographic orientations of the high-temperature body-centered cubic prior-β grains. The combination of these data has been used to gain an understanding of the role of the prior-β grain structure in the formation of specific morphologies and spatial misorientation distributions observed in the transformed α colony structures. It is hoped that this understanding can be used to develop transformation structures optimized for specific applications and to produce more physically realistic synthetic microstructures for use in simulations.

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Three-dimensional grain resolved strain mapping using laboratory X-ray diffraction contrast tomography: theoretical analysis

Journal of Applied Crystallography ◽

10.1107/s1600576721011274 ◽

2022 ◽

Vol 55 (1) ◽

Author(s):

Adam Lindkvist ◽

Yubin Zhang

Keyword(s):

Near Field ◽

Three Dimensional ◽

Simulated Data ◽

Three Dimensions ◽

X Ray Diffraction ◽

Strain Mapping ◽

X Ray ◽

Microstructural Parameters ◽

Diffraction Contrast ◽

Sample Distance

Laboratory diffraction contrast tomography (LabDCT) is a recently developed technique to map crystallographic orientations of polycrystalline samples in three dimensions non-destructively using a laboratory X-ray source. In this work, a new theoretical procedure, named LabXRS, expanding LabDCT to include mapping of the deviatoric strain tensors on the grain scale, is proposed and validated using simulated data. For the validation, the geometries investigated include a typical near-field LabDCT setup utilizing Laue focusing with equal source-to-sample and sample-to-detector distances of 14 mm, a magnified setup where the sample-to-detector distance is increased to 200 mm, a far-field Laue focusing setup where the source-to-sample distance is also increased to 200 mm, and a near-field setup with a source-to-sample distance of 200 mm. The strain resolution is found to be in the range of 1–5 × 10−4, depending on the geometry of the experiment. The effects of other experimental parameters, including pixel binning, number of projections and imaging noise, as well as microstructural parameters, including grain position, grain size and grain orientation, on the strain resolution are examined. The dependencies of these parameters, as well as the implications for practical experiments, are discussed.

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X-ray diffraction contrast tomography: a novel technique for three-dimensional grain mapping of polycrystals. I. Direct beam case

Journal of Applied Crystallography ◽

10.1107/s0021889808001684 ◽

2008 ◽

Vol 41 (2) ◽

pp. 302-309 ◽

Cited By ~ 146

Author(s):

Wolfgang Ludwig ◽

Søeren Schmidt ◽

Erik Mejdal Lauridsen ◽

Henning Friis Poulsen

Keyword(s):

Three Dimensional ◽

Reconstruction Technique ◽

X Ray Diffraction ◽

X Ray ◽

Direct Beam ◽

Novel Technique ◽

Diffraction Contrast ◽

Orientation Space ◽

Grain Orientations ◽

Projection Images

The principles of a novel technique for nondestructive and simultaneous mapping of the three-dimensional grain and the absorption microstructure of a material are explained. The technique is termed X-ray diffraction contrast tomography, underlining its similarity to conventional X-ray absorption contrast tomography with which it shares a common experimental setup. The grains are imaged using the occasionally occurring diffraction contribution to the X-ray attenuation coefficient each time a grain fulfils the diffraction condition. The three-dimensional grain shapes are reconstructed from a limited number of projections using an algebraic reconstruction technique. An algorithm based on scanning orientation space and aiming at determining the corresponding crystallographic grain orientations is proposed. The potential and limitations of a first approach, based on the acquisition of the direct beam projection images only, are discussed in this first part of the paper. An extension is presented in the second part of the paper [Johnson, King, Honnicke, Marrow & Ludwig (2008).J. Appl. Cryst.41, 310–318], addressing the case of combined direct and diffracted beam acquisition.

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3D grain structure of an extruded 6061 Al alloy by lab-scale X-ray diffraction contrast tomography (DCT)

Materials Characterization ◽

10.1016/j.matchar.2020.110716 ◽

2020 ◽

Vol 170 ◽

pp. 110716

Author(s):

Yongfeng Zhao ◽

Sridhar Niverty ◽

Xia Ma ◽

Xiangfa Liu ◽

Nikhilesh Chawla

Keyword(s):

Grain Structure ◽

Al Alloy ◽

X Ray Diffraction ◽

X Ray ◽

Diffraction Contrast ◽

6061 Al Alloy

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Three Dimensional X-ray Diffraction Contrast Tomography Reconstruction of Polycrystalline Strontium Titanate during Sintering and Electron Backscatter Diffraction Validation

2ndWorld Congress on Integrated Computational Materials Engineering ◽

10.1002/9781118767061.ch42 ◽

2013 ◽

pp. 259-264

Author(s):

M. Syha ◽

W. Rheinheimer ◽

B. Loedermann ◽

A. Graff ◽

A. Trenkle ◽

...

Keyword(s):

Strontium Titanate ◽

Electron Backscatter Diffraction ◽

Three Dimensional ◽

X Ray Diffraction ◽

X Ray ◽

Diffraction Contrast ◽

Electron Backscatter ◽

Tomography Reconstruction ◽

Backscatter Diffraction

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Improved grain mapping by laboratory X-ray diffraction contrast tomography

IUCrJ ◽

10.1107/s2052252521003730 ◽

2021 ◽

Vol 8 (4) ◽

Author(s):

H. Fang ◽

D. Juul Jensen ◽

Y. Zhang

Keyword(s):

Spatial Resolution ◽

Ground Truth ◽

Shape Reconstruction ◽

Grain Structure ◽

Forward Simulation ◽

X Ray Diffraction ◽

X Ray ◽

Diffraction Contrast ◽

Iron Sample ◽

Non Destructive

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 µm than for larger grains. The underlying reasons are clarified by comparing spot features for different LabDCT datasets using a forward simulation tool.

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