scholarly journals Voxel-based strain tensors from near-field High Energy Diffraction Microscopy

2020 ◽  
Vol 24 (4) ◽  
pp. 100852
Author(s):  
Yu-Feng Shen ◽  
He Liu ◽  
Robert M. Suter
Keyword(s):  
Near Field ◽  
High Energy ◽  
Strain Tensors ◽  
Diffraction Microscopy

scholarly journals 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

2015 ◽  
Vol 48 (4) ◽  
pp. 1165-1171 ◽  
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.

Demonstration of near Field High Energy X-Ray Diffraction Microscopy on High-Z Ceramic Nuclear Fuel Material

2014 ◽  
Vol 777 ◽  
pp. 112-117 ◽  
Author(s):  
Donald W. Brown ◽  
Levente Balogh ◽  
Darrin Byler ◽  
Chris M. Hefferan ◽  
James F. Hunter ◽  
...  
Keyword(s):  
Nuclear Fuel ◽  
Near Field ◽  
Grain Morphology ◽  
High Energy ◽  
X Ray Diffraction ◽  
Boundary Misorientation ◽  
Sintered Ceramic ◽  
X Ray ◽  
Diffraction Microscopy ◽  
Fuel Material

Near-field high energy x-ray diffraction microscopy (nf-HEDM) and high energy x-ray micro-tomography (μT) have been utilized to characterize the pore structure and grain morphology in sintered ceramic UO2nuclear fuel material. μT successfully images pores to 2-3μm diameters and is analyzed to produce a pore size distribution. It is apparent that the largest number of pores and pore volume in the sintered ceramic are below the current resolution of the technique, which might be more appropriate to image cracks in the same ceramics. Grain orientation maps of slices determined by nf-HEDM at 25 μm intervals are presented and analyzed in terms of grain boundary misorientation angle. The benefit of these two techniques is that they are non-destructive and thus could be performed before and after processes (such as time at temperature or in-reactor) or even in-situ.

Tests of microstructure reconstruction by forward modeling of high energy X-ray diffraction microscopy data

2010 ◽  
Vol 25 (2) ◽  
pp. 132-137 ◽  
Author(s):  
C. M. Hefferan ◽  
S. F. Li ◽  
J. Lind ◽  
R. M. Suter
Keyword(s):  
Near Field ◽  
Simulated Data ◽  
Forward Modeling ◽  
High Energy ◽  
Data Sets ◽  
Geometric Accuracy ◽  
X Ray Diffraction ◽  
Detector Resolution ◽  
X Ray ◽  
Diffraction Microscopy

Verification tests of the forward modeling technique for near-field high energy X-ray diffraction microscopy are conducted using two simulated microstructures containing uniformly distributed orientations. Comparison between the simulated and reconstructed microstructures is examined with consideration to both crystallographic orientation and spatial geometric accuracy. To probe the dependence of results on experimental parameters, simulated data sets use two different detector configurations and different simulated experimental protocols; in each case, the parameters mimic the experimental geometry used at Advanced Photon Source beamline 1-ID. Results indicate that element orientations are distinguishable to less than 0.1°, while spatial geometric accuracy is limited by the detector resolution.

Accuracy and precision of near-field high-energy diffraction microscopy forward-model-based microstructure reconstructions

2020 ◽  
Vol 53 (1) ◽  
pp. 107-116 ◽  
Author(s):  
D. B. Menasche ◽  
P. A. Shade ◽  
R. M. Suter
Keyword(s):  
Data Collection ◽  
Electron Backscatter Diffraction ◽  
Near Field ◽  
Ground Truth ◽  
High Energy ◽  
Standard Data ◽  
Imaging Detector ◽  
Backscatter Diffraction ◽  
Diffraction Microscopy ◽  
Better Than

The accuracy of the near-field high-energy diffraction microscopy (nf-HEDM) technique is evaluated by directly comparing an nf-HEDM reconstructed microstructure with an electron backscatter diffraction (EBSD) characterization of the same microstructure. A high-purity gold oligocrystal was chosen for characterization in order to facilitate direct one-to-one comparison between the reconstructions given by each technique. By using the comparatively high spatial resolution of the EBSD reconstruction as the ground truth for the grain-boundary network's morphology, it is determined that nf-HEDM locates internal grain boundaries with an accuracy on average better than the resolution of the imaging detector used or within the reconstruction voxel size, whichever is larger. By taking the intragranular misorientation in well ordered grains as a proxy for orientation resolution, it is determined that standard data collection procedures determine crystallographic orientations to better than 0.1°. The effects of various modified data collection procedures are also examined.

Measuring stress-induced martensite microstructures using far-field high-energy diffraction microscopy

2018 ◽  
Vol 74 (5) ◽  
pp. 425-446 ◽  
Author(s):  
Ashley Nicole Bucsek ◽  
Darren Dale ◽  
Jun Young Peter Ko ◽  
Yuriy Chumlyakov ◽  
Aaron Paul Stebner
Keyword(s):  
Phase Transformation ◽  
Three Dimensional ◽  
Infinite Plate ◽  
Direct Analysis ◽  
High Energy ◽  
Data Sets ◽  
Far Field ◽  
X Ray Diffraction ◽  
Parent Austenite ◽  
Diffraction Microscopy

Modern X-ray diffraction techniques are now allowing researchers to collect long-desired experimental verification data sets that are in situ, three-dimensional, on the same length scales as critical microstructures, and using bulk samples. These techniques need to be adapted for advanced material systems that undergo combinations of phase transformation, twinning and plasticity. One particular challenge addressed in this article is direct analysis of martensite phases in far-field high-energy diffraction microscopy experiments. Specifically, an algorithmic forward model approach is presented to analyze phase transformation and twinning data sets of shape memory alloys. In the present implementation of the algorithm, the crystallographic theory of martensite (CTM) is used to predict possible martensite microstructures (i.e. martensite orientations, twin mode, habit plane, twin plane and twin phase fractions) that could form from the parent austenite structure. This approach is successfully demonstrated on three single- and near-single-crystal NiTi samples where the fundamental assumptions of the CTM are not upheld. That is, the samples have elastically strained lattices, inclusions, precipitates, subgrains, R-phase transformation and/or are not an infinite plate. The results indicate that the CTM still provides structural solutions that match the experiments. However, the widely accepted maximum work criterion for predicting which solution of the CTM should be preferred by the material does not work in these cases. Hence, a more accurate model that can simulate these additional structural complexities can be used within the algorithm in the future to improve its performance for non-ideal materials.

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