scholarly journals Improved grain mapping by laboratory X-ray diffraction contrast tomography

IUCrJ ◽  
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.

scholarly journals A flexible and standalone forward simulation model for laboratory X-ray diffraction contrast tomography

2020 ◽  
Vol 76 (6) ◽  
pp. 652-663 ◽  
Author(s):  
H. Fang ◽  
D. Juul Jensen ◽  
Y. Zhang
Keyword(s):  
Crystal Structure ◽  
Simulation Model ◽  
Forward Simulation ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
X Ray ◽  
Diffraction Contrast ◽  
Input Structure ◽  
Grain Orientations ◽  
Non Destructive

Laboratory X-ray diffraction contrast tomography (LabDCT) has recently been developed as a powerful technique for non-destructive mapping of grain microstructures in bulk materials. As the grain reconstruction relies on segmentation of diffraction spots, it is essential to understand the physics of the diffraction process and resolve all the spot features in detail. To this aim, a flexible and standalone forward simulation model has been developed to compute the diffraction projections from polycrystalline samples with any crystal structure. The accuracy of the forward simulation model is demonstrated by good agreements in grain orientations, boundary positions and shapes between a virtual input structure and that reconstructed based on the forward simulated diffraction projections of the input structure. Further experimental verification is made by comparisons of diffraction spots between simulations and experiments for a partially recrystallized Al sample, where a satisfactory agreement is found for the spot positions, sizes and intensities. Finally, applications of this model to analyze specific spot features are presented.

scholarly journals Quantitative non-destructive 3D Crystallographic Imaging of Microstructures using Laboratory X-ray Diffraction Contrast Tomography

2018 ◽  
Vol 24 (S2) ◽  
pp. 554-555
Author(s):  
Hrishikesh Bale ◽  
Ron Kienan ◽  
Stephen T Kelly ◽  
Nicolas Gueninchault ◽  
Erik Lauridsen ◽  
...  
Keyword(s):  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Contrast ◽  
Non Destructive

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

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

Effect of Coating with Hydroxyapatite on the Bonding of Bone to Implant

2012 ◽  
Vol 706-709 ◽  
pp. 1661-1666
Author(s):  
Abdelilah Benmarouane ◽  
Pierre Millet ◽  
Thomas Buslaps ◽  
Alain Lodini ◽  
Veijo Honkimäki
Keyword(s):  
Synchrotron Radiation ◽  
Spatial Resolution ◽  
Orthopaedic Surgery ◽  
High Spatial Resolution ◽  
High Energy ◽  
Direct Connection ◽  
X Ray Diffraction ◽  
X Ray ◽  
Natural Bone ◽  
Non Destructive

The aim of the present study was to study the interface implant-bone by synchrotron radiation, the implant has two faces the first one coated with hydroxyapatite and the second uncoated. In orthopaedic surgery, Titanium (Ti-Al-4V) implants are currently coated with hydroxyapatite (HAp), Ca10(PO4)6(OH)2, in order to obtain a stable and functional direct connection between the bone and the implant. At the implant-bone interface, the new bone reconstituted after two months of implantation must have the same properties like the natural bone in order to accept the implant. Therefore we studied the texture of the reconstituted bone crystals at the interface applying non destructive x-ray diffraction. The required high spatial resolution was achieved utilizing high-energy synchrotron radiation on ID15 at ESRF in Grenoble, France.

scholarly journals X-ray fan beam coded aperture transmission and diffraction imaging for fast material analysis

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Stefan Stryker ◽  
Joel A. Greenberg ◽  
Shannon J. McCall ◽  
Anuj J. Kapadia
Keyword(s):  
High Resolution ◽  
Spatial Resolution ◽  
Imaging System ◽  
Coded Aperture ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Imaging ◽  
Diffraction Imaging ◽  
Non Destructive ◽  
Ray Methods

AbstractX-ray transmission imaging has been used in a variety of applications for high-resolution measurements based on shape and density. Similarly, X-ray diffraction (XRD) imaging has been used widely for molecular structure-based identification of materials. Combining these X-ray methods has the potential to provide high-resolution material identification, exceeding the capabilities of either modality alone. However, XRD imaging methods have been limited in application by their long measurement times and poor spatial resolution, which has generally precluded combined, rapid measurements of X-ray transmission and diffraction. In this work, we present a novel X-ray fan beam coded aperture transmission and diffraction imaging system, developed using commercially available components, for rapid and accurate non-destructive imaging of industrial and biomedical specimens. The imaging system uses a 160 kV Bremsstrahlung X-ray source while achieving a spatial resolution of ≈ 1 × 1 mm2 and a spectral accuracy of > 95% with only 15 s exposures per 150 mm fan beam slice. Applications of this technology are reported in geological imaging, pharmaceutical inspection, and medical diagnosis. The performance of the imaging system indicates improved material differentiation relative to transmission imaging alone at scan times suitable for a variety of industrial and biomedical applications.

scholarly journals 3D grain reconstruction from laboratory diffraction contrast tomography

2019 ◽  
Vol 52 (3) ◽  
pp. 643-651 ◽  
Author(s):  
Florian Bachmann ◽  
Hrishikesh Bale ◽  
Nicolas Gueninchault ◽  
Christian Holzner ◽  
Erik Mejdal Lauridsen
Keyword(s):  
Three Dimensional ◽  
Solution Space ◽  
Grain Structure ◽  
X Ray Diffraction ◽  
Shape Information ◽  
X Ray ◽  
Reconstruction Scheme ◽  
Diffraction Contrast ◽  
Tomography System ◽  
Diffraction Geometry

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.

Diffraction Contrast Tomography - A Synchrotron Radiation Technique for Mapping Polycrystalline Microstructures in 3D

2008 ◽  
Vol 571-572 ◽  
pp. 207-212 ◽  
Author(s):  
Andrew King ◽  
Greg Johnson ◽  
Wolfgang Ludwig
Keyword(s):  
X Ray Diffraction ◽  
Transmitted Beam ◽  
X Ray ◽  
Diffraction Contrast ◽  
Diffraction Geometry ◽  
Radiation Technique ◽  
Non Destructive ◽  
Diffraction Microscopy

In this paper the authors describe a technique based on synchrotron x-ray diffraction which has been used to produce full 3D grain maps (both grain shapes and orientations) in annealed aluminium alloy and stainless steel samples containing around 500 grains. The procedure is termed diffraction contrast tomography (DCT), reflecting its similarities with conventional absorption contrast tomography. It is an extension of the 3D X-ray diffraction microscopy (3DXRD) concept, and has been developed in collaboration with its inventors. The specimen is illuminated using a monochromatic synchrotron x-ray beam, and grains imaged using the extinction contrast that appears in the transmitted beam when grains are aligned in the diffraction condition during rotation of the sample. The beams of radiation diffracted by the grains are captured simultaneously on the same detector as the direct beam image. The combination of diffraction and extinction information aids the grain indexing operation, in which pairs of diffraction and extinction images are assigned to grain sets. 3D grain shapes are determined by algebraic reconstruction from the limited number of extinction projections, while crystallographic orientation is found from the diffraction geometry. The non-destructive nature of the technique allows for in-situ studies of mapped samples. Research is in progress to extend the technique to allow the determination of the elastic strain and stress tensors on a grain-by-grain basis.

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

2012 ◽  
Vol 66 (1) ◽  
pp. 1-4 ◽  
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

scholarly journals Optimizing laboratory X-ray diffraction contrast tomography for grain structure characterization of pure iron

2021 ◽  
Vol 54 (1) ◽  
Author(s):  
Adam Lindkvist ◽  
Haixing Fang ◽  
Dorte Juul Jensen ◽  
Yubin Zhang
Keyword(s):  
Exposure Time ◽  
Structure Characterization ◽  
Grain Structure ◽  
X Ray ◽  
Diffraction Contrast ◽  
Tomography System ◽  
Iron Sample ◽  
Diffraction Patterns ◽  
3D Volume

Laboratory diffraction contrast tomography (LabDCT) is a recently developed technique for 3D nondestructive grain mapping using a conical polychromatic beam from a laboratory-based X-ray source. The effects of experimental parameters, including accelerating voltage, exposure time and number of projections used for reconstruction, on the characterization of the 3D grain structure in an iron sample are quantified. The experiments were conducted using a commercial X-ray tomography system, ZEISS Xradia 520 Versa, equipped with a LabDCT module; and the data analysis was performed using the software package GrainMapper3D, which produces a 3D reconstruction from binarized 2D diffraction patterns. It is found that the exposure time directly affects the background noise level and thus the ability to distinguish weak spots of small grains from the background. With the assistance of forward simulations, it is found that spots from the first three strongest {hkl} families of a large grain can be seen with as few as 30–40 projections, which is sufficient for indexing the crystallographic orientation and resolving the grain shape with a reasonably high accuracy. It is also shown that the electron current is a more important factor than the accelerating voltage to be considered for optimizing the photon numbers with energies in the range of 20–60 keV. This energy range is the most important one for diffraction of common metals, e.g. iron and aluminium. Several suggestions for optimizing LabDCT experiments and 3D volume reconstruction are finally provided.

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