Comparative investigation of two-dimensional imaging methods and X-ray tomography in the characterization of microstructure

Bacaicoa, I.; Lütje, Martin; Sälzer, P.; Umbach, Cristin; Brückner‐Foit, A.; Heim, Hans-Peter; Middendorf, Bernhard

doi:10.3139/120.111076

Cited by 11 publications

(9 citation statements)

References 17 publications

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“…Therefore, we suggest it would be better in the future to use Feret diameter measurements rather than mesh size or particle diameter to classify the wood reinforcement used to manufacture WPCs. This suggestion is supported by the research of Bacaicoa et al who obtained Feret-based parameters from wood particles segmented in X-ray micro-CT images [20].…”

Section: Discussionsupporting

confidence: 52%

“…X-ray microcomputed tomography (CT) is increasingly used to characterize the microstructure of polymer and aerospace composites and examine either experimentally or computationally the relationship between microstructure and bulk composite properties [13,14]. X-ray micro-CT has also been used to characterize the microstructure of wood composites, including wood plastic composites [3,[15][16][17][18][19][20]. Characterization of wood plastic composites using X-ray micro-CT is challenging because, as pointed out by Wang et al [3], 'plastics and wood are both weak in X-ray attenuation, and this always causes insufficient contrast in X-ray images and inability to separate wood particles from plastic'.…”

Section: Introductionmentioning

confidence: 99%

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Sodium Iodide as a Contrast Agent for X-ray Micro-CT of a Wood Plastic Composite

2021

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The properties of wood plastic composites (WPCs) depend on their microstructure, particularly the level and geometry of wood reinforcement in the composite. We hypothesize that impregnating a WPC with a radiocontrast agent will increase the contrast between wood and plastic, allowing better visualization of its microstructure and numerical analysis of the geometry of its wood reinforcement. A commercial WPC was scanned using X-ray micro-CT, impregnated with aqueous sodium iodide, and then rescanned. CT data from both scans were visualized, and we analyzed the geometry of wood reinforcement and levels of wood, plastic, zinc borate (ZB), and voids in the WPC. ZB occurred mainly as discrete particles between wood flakes, and interfacial voids formed a network of cracks within the WPC. Sodium iodide labeling made it possible to clearly visualize wood and plastic in the WPC and quantify levels of different phases and the geometry of wood particles. However, sodium iodide was not an ideal contrast agent because it swelled wood particles, closed interfacial voids, and partially dissolved ZB particles. We suggest methods of overcoming these limitations and conclude that advances in labeling are necessary to improve our understanding of the relationship between the microstructure of WPCs and their properties.

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Section: Discussionsupporting

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Sodium Iodide as a Contrast Agent for X-ray Micro-CT of a Wood Plastic Composite

2021

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“…In contrast to micrographs, µCT allows a three-dimensional representation of the microstructure and thus also of the fibers in the composites without destroying them [ 30 ]. This also increases the accuracy of the determined geometrical and positional properties of the fibers or fillers [ 20 , 31 ].…”

Section: Introductionmentioning

confidence: 99%

Comparison of Real and Simulated Fiber Orientations in Injection Molded Short Glass Fiber Reinforced Polyamide by X-ray Microtomography

et al. 2021

Self Cite

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During injection molding of short glass fiber reinforced composites, a complex structure is formed due to the fiber movement. The resulting fiber orientation can be predicted using various simulation models. However, the models are known to have inadequacies andthe influence of process and model parameters is not clearly and comprehensively described. In this study, the aforementioned model and process parameters are investigated to determine the dependencies of the individual influences on the real and simulated fiber orientation. For this purpose, specimens are injection molded at different process parameters. Representative regions of the specimens are measured using X-ray microtomography and dynamic image analysis to determine the geometric properties of the fibers as well as their orientations. Furthermore, simulations are performed with the simulation software Moldflow® using different mesh types and densities as well as varying parameters of the MRD model to represent the real fiber orientations. The results show that different orientation areas arise in the samples, which cannot be represented with a simulation varying only one parameter. Several simulations must be carried out in order to represent flow regions occurring in the specimen as realistically as possible.

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“…The nondestructive ultrasonic or laser ultrasonic techniques were used to analyze the porosity level in welds [13,14,19]. X-ray techniques have also become the commonly used methods to detect pores in welds [20,21]. Industrial computed tomography (ICT) has been used to determine the porosity and the number of pores in fabricated parts and in a single weld [6,18].…”

Section: Introductionmentioning

confidence: 99%

Mechanism to Reduce the Porosity during Argon Arc Welding of Aluminum Alloys by Changing the Arc Angle

Chen

Chi

Zhang

et al. 2020

Metals

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A mechanism to reduce the porosity by changing the arc angle during aluminum alloy welding was studied. Industrial computed tomography was used to scan the welds with different arc angles, and the scanned model was processed by a specific software package to obtain the digital size and position of weld pores. The forces acting on the pores in the molten pool explained the test results that the number of pores decreases and the average size increases. As the inclination angle of the arc increased, the vertical component that prevented the bubble from rising decreased, and the horizontal component that pushed the molten metal flow and promoted the nucleation and growth of the bubbles increased. A horizontal movement during the droplet transition as the arc inclination was produced, which was conducive to the growth and overflow of bubbles. The theoretical analysis and temperature field measured by a far-infrared with different torch angle showed that when the arc was tilted from 0, the shape of the molten pool changed from the circle to the ellipse. The long axis of the ellipse increased as the bevel angle of the arc increased. This showed that the molten metal existed a longer time for the bubbles to escape from the molten pool when the angle of the arc increased. The paper provides fundamental insights into a mechanism for porosity reduction during the welding of Al alloys.

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Comparative investigation of two-dimensional imaging methods and X-ray tomography in the characterization of microstructure

Cited by 11 publications

References 17 publications

Sodium Iodide as a Contrast Agent for X-ray Micro-CT of a Wood Plastic Composite

Sodium Iodide as a Contrast Agent for X-ray Micro-CT of a Wood Plastic Composite

Comparison of Real and Simulated Fiber Orientations in Injection Molded Short Glass Fiber Reinforced Polyamide by X-ray Microtomography

Mechanism to Reduce the Porosity during Argon Arc Welding of Aluminum Alloys by Changing the Arc Angle

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