Three-dimensional visualization and quantification of microporosity in aluminum castings by X-ray micro-computed tomography

2021 ◽  
Vol 65 ◽  
pp. 99-107
Author(s):  
Cheng Gu ◽  
Yan Lu ◽  
Alan A. Luo
2019 ◽  
Vol 34 (2) ◽  
pp. 97-102
Author(s):  
M. A. Rodriguez ◽  
T. T. Amon ◽  
J. J. M. Griego ◽  
H. Brown-Shaklee ◽  
N. Green

Advancements in computer technology have enabled three-dimensional (3D) reconstruction, data-stitching, and manipulation of 3D data obtained on X-ray imaging systems such as micro-computed tomography (μ-CT). Likewise, intuitive evaluation of these 3D datasets can be enhanced by recent advances in virtual reality (VR) hardware and software. Additionally, the generation, viewing, and manipulation of 3D X-ray diffraction datasets, such as pole figures employed for texture analysis, can also benefit from these advanced visualization techniques. We present newly-developed protocols for porting 3D data (as TIFF-stacks) into a Unity gaming software platform so that data may be toured, manipulated, and evaluated within a more-intuitive VR environment through the use of game-like controls and 3D headsets. We demonstrate this capability by rendering μ-CT data of a polymer dogbone test bar at various stages of in situ mechanical strain. An additional experiment is presented showing 3D XRD data collected on an aluminum test block with vias. These 3D XRD data for texture analysis (χ, ϕ, 2θ dimensions) enables the viewer to visually inspect 3D pole figures and detect the presence or absence of in-plane residual macrostrain. These two examples serve to illustrate the benefits of this new methodology for multidimensional analysis.


2019 ◽  
Vol 809 ◽  
pp. 587-593
Author(s):  
Simon Zabler ◽  
Katja Schladitz ◽  
Kilian Dremel ◽  
Jonas Graetz ◽  
Dascha Dobrovolskij

To detect and characterize materials defects in fiber composites as well as for evaluatingthe three-dimensional local fiber orientation in the latter, X-ray micro-CT is the preferred methodof choice. When micro computed tomography is applied to inspect large components, the method isreferred to as region-of-interest computed tomography. Parts can be as large as 10 cm wide and 1 mlong, while the measurement volume of micro computed tomography is a cylinder of only 4 − 5 mmdiameter (typical wall thickness of fiber composite parts). In this report, the potentials and limits ofregion-of-interest computed tomography are discussed with regard to spatial resolution and precisionwhen evaluating defects and local fiber orientation in squeeze cast components. The micro computedtomography scanner metRIC at Fraunhofer‘s Development Center X-ray Technology EZRT deliversregion-of-interest computed tomography up to a spatial resolution of 2 μm/voxel, which is sufficientfor determining the orientation of natural or synthetic fibers, wood, carbon and glass. The mean localfiber orientation is estimated on an isotropic structuring element of approximately 0.1 mm length bymeans of volume image analysis (MAVI software package by Fraunhofer ITWM). Knowing the exactlocal fiber orientation is critical for estimating anisotropic thermal conductivity and materials strength.


Author(s):  
Daniel H. Morse ◽  
Arlyn J. Antolak ◽  
Bernice E. Mills

X-ray radiography has long been recognized as a valuable tool for detecting internal features and flaws. Recent developments in microfabrication and composite materials have extended inspection requirements to the resolution limits of conventional radiography. Our work has been directed toward pushing both detection and measurement capabilities to a smaller scale. Until recently, we have used conventional contact radiography, optimized to resolve small features. With the recent purchase of a nano-focus (sub-micron) x-ray source, we are now investigating projection radiography, phase contrast imaging and micro-computed tomography (μ-CT). Projection radiography produces a magnified image that is limited in spatial resolution mainly by the source size, not by film grain size or detector pixel size. Under certain conditions phase contrast can increase the ability to resolve small features such as cracks, especially in materials with low absorption contrast. Micro-computed tomography can provide three-dimensional measurements on a micron scale and has been shown to provide better sensitivity than simple radiographs. We have included applications of these techniques to small-scale measurements not easily made by mechanical or optical means. Examples include void detection in meso-scale nickel MEMS parts, measurement of edge profiles in thick gold lithography masks, and characterization of the distribution of phases in composite materials. Our work, so far, has been limited to film.


2020 ◽  
Vol 94 (3) ◽  
pp. 417-435 ◽  
Author(s):  
Sarah Kachovich ◽  
Jonathan C. Aitchison

AbstractA new, previously undescribed Middle Ordovician (middle Darriwilian: Dw2) radiolarian assemblage has been recovered from the Table Cove Formation at Piccadilly Quarry, western Newfoundland. Constituents of the fauna described herein are both distinctive and exceptionally well preserved. Three-dimensional X-ray micro-computed tomography (μ-CT) is used to make a detailed examination of four key spumellarian specimens. This technology enables visualization of hitherto ambiguous details of the internal morphologies of key lower Paleozoic taxonomic groups, among which a lack of knowledge has impeded resolution of higher taxonomic rankings.


2004 ◽  
Vol 339 (1-2) ◽  
pp. 125-130 ◽  
Author(s):  
A.C. Jones ◽  
A.P. Sheppard ◽  
R.M. Sok ◽  
C.H. Arns ◽  
A. Limaye ◽  
...  

Author(s):  
M. Freire-Gormaly ◽  
H. MacLean ◽  
A. Bazylak

In this paper, we characterized the microstructure of Indiana Limestone rock samples using X-ray micro-computed tomography (microCT) measurements. Our preliminary results include the porosity, and three-dimensional pore reconstructions for each sample. The resulting porosity values are consistent with experimental permeability tests.


2021 ◽  
pp. 1-31
Author(s):  
Sarah Kachovich ◽  
Jonathan C. Aitchison

Abstract New, distinctive, well-preserved and previously undescribed constituents of a Middle Ordovician (middle Darriwilian, Dw2) radiolarian assemblage from the Table Cove Formation in Newfoundland are described. Three-dimensional X-ray micro-computed tomography (μ-CT) facilitates detailed examination of key specimens revealing hitherto unknown details of the internal morphologies of key lower Paleozoic taxonomic groups, among which a lack of knowledge has previously impeded resolution of higher taxonomic rankings. Twenty-seven archaeospiculid and entactinarian taxa are described and illustrated including six new species: Westernbrookia polygonata n. sp., Neopalaeospiculum piccadilliensis n. sp., Ramuspiculum laxum n. sp. Spongentactinia nazarovi n. sp., Aspiculum irregulare n. sp., and Nyfrieslandia ramosissima n. sp. The investigation extends the known ranges of the species: Pararcheoentactinia reedae Won and Iams, 2002; Sphaeroentactinia robusta Won and Iams, 2015; Varispiculum ectospiculatum Won and Iams, 2015; and Svalbardospiculum multifurcatum (Won, Iams, and Reed, 2005), together with the genus Echidnina to the mid-Darriwilian. UUID: http://zoobank.org/74826b7b-bb86-45d5-ad23-e6e65e0706df.


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