Laboratory Computed X-Ray Tomography – A Nondestructive Technique for 3D Microstructure Analyis of Materials

Zschech, Ehrenfried; Löffler, Markus; Krüger, Peter; Gluch, Jürgen; Kutukova, Kristina; Zgłobicka, Izabela; Silomon, Jendrik; Rosenkranz, Rüdiger; Standke, Yvonne; Topal, Emre

doi:10.3139/147.110537

Cited by 21 publications

(17 citation statements)

References 15 publications

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“…Further development of nondestructive tomographic techniques as they have already been presented above with qualitative imaging may contribute. The current capabilities of laboratory computed X-ray tomography 94 do not allow to gain sufficient quantitative insight into filigree structures of larger metallic objects such as chunky graphite in cast iron materials. On the other hand, time-resolved and spatial resolution synchrotron tomography methods, for which a recent overview on status and perspectives was presented in Reference 95, offer resolution advantages with bigger metallic objects at the expense of high experimental effort and costs.…”

Section: Advanced Characterization Techniques and Quantification Of Cmentioning

confidence: 99%

Chunky Graphite in Ferritic Spheroidal Graphite Cast Iron: Formation, Prevention, Characterization, Impact on Properties: An Overview

Baer

2019

Inter Metalcast

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Ferritic spheroidal graphite cast iron (SGI) materials have a remarkable technical potential and economic impact in modern industry. These features are closely related to the question of how the cast materials can be produced without structural defects and graphite degenerations such as, for example, chunky graphite. Although the chunky graphite degeneration superficially seems to be well known, its metallurgical background is still controversially discussed, appropriate field-tested nondestructive tools for its quantification in castings are lacking, and the knowledge on its impact on material properties is fairly limited. Addressing this status, the article is providing a current overview on the subject. Existing theories on formation and growth mechanisms of chunky graphite are briefly reviewed. Furthermore, from a metallurgical point of view, causes for the appearance of chunky graphite as well as preventive measures are concisely summarized. Particular attention is paid to the morphology of chunky graphite and how it can be characterized by destructive and nondestructive techniques. Special emphasis was laid on providing a comprehensive overview on the impact of chunky graphite on strength, ductility, fatigue limit, fatigue crack growth rate as well as fracture toughness of ferritic SGI materials based on experimental data. Moreover, conclusions for the assessment of castings affected by chunky graphite are drawn.

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Section: Advanced Characterization Techniques and Quantification Of Cmentioning

confidence: 99%

Chunky Graphite in Ferritic Spheroidal Graphite Cast Iron: Formation, Prevention, Characterization, Impact on Properties: An Overview

Baer

2019

Inter Metalcast

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“…In situ micromechanical compression tests were performed inside the nano-XCT system with an in-house-developed micromechanical test setup [ 36 ]. For the mechanical testing, a single fossil frustule from genera of Ellerbeckia and Melosira was selected and compressed between two flat surfaces (bottom: steel sample holder, top: diamond flat punch) by stepwise increasing loads.…”

Section: Methodsmentioning

confidence: 99%

Morphology and Mechanical Properties of Fossil Diatom Frustules from Genera of Ellerbeckia and Melosira

Gluch

Liao

et al. 2021

Nanomaterials

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Fossil frustules of Ellerbeckia and Melosira were studied using laboratory-based nano X-ray tomography (nano-XCT), transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDS). Three-dimensional (3D) morphology characterization using nondestructive nano-XCT reveals the continuous connection of fultoportulae, tube processes and protrusions. The study confirms that Ellerbeckia is different from Melosira. Both genera reveal heavily silicified frustules with valve faces linking together and forming cylindrical chains. For this cylindrical architecture of both genera, valve face thickness, mantle wall thickness and copulae thickness change with the cylindrical diameter. Furthermore, EDS reveals that these fossil frustules contain Si and O only, with no other elements in the percentage concentration range. Nanopores with a diameter of approximately 15 nm were detected inside the biosilica of both genera using TEM. In situ micromechanical experiments with uniaxial loading were carried out within the nano-XCT on these fossil frustules to determine the maximal loading force under compression and to describe the fracture behavior. The fracture force of both genera is correlated to the dimension of the fossil frustules. The results from in situ mechanical tests show that the crack initiation starts either at very thin features or at linking structures of the frustules.

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“…The combination of nano-XCT studies with in-situ micromechanical experiments merges the advantage of nondestructive high-resolution 3D imaging of the microstructure of materials with the observation of phenomena like crack initiation, crack propagation, and delamination during mechanical loading. For these studies, a laboratory transmission X-ray microscope Xradia Nano-XCT-100 (Concord, California) operated at a photon energy of 8.0 keV (Cu-Kα radiation) [20][21][22] was used during the micro-indentation test to visualize the crack propagation. A detailed experimental setup was described elsewhere by Zgłobicka et al [23].…”

Section: Methodsmentioning

confidence: 99%

“…The mechanical loading of the shell was performed within the nano-XCT system using a customized micro-mechanical testing system which was designed for in-situ micro-indentation experiments in such a way that it fits into the limited space of the nano-XCT tool in particular and that the indenter tip and the sample fits into the field of view of the X-ray microscope. The system has been described by Zschech et al [21]. The indentation tests in the XCT were performed, the same as compression tests, along two directions, i.e., ND and LD, using a cube corner tip.…”

Section: Methodsmentioning

confidence: 99%

Anisotropy of Mechanical Properties of Pinctada margaritifera Mollusk Shell

et al. 2020

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The mechanical properties such as compressive strength and nanohardness were investigated for Pinctada margaritifera mollusk shells. The compressive strength was evaluated through a uniaxial static compression test performed along the load directions parallel and perpendicular to the shell axis, respectively, while the hardness and Young modulus were measured using nanoindentation. In order to observe the crack propagation, for the first time for such material, the in-situ X-ray microscopy (nano-XCT) imaging (together with 3D reconstruction based on the acquired images) during the indentation tests was performed. The results were compared with these obtained during the micro-indentation test done with the help of conventional Vickers indenter and subsequent scanning electron microscopy observations. The results revealed that the cracks formed during the indentation start to propagate in the calcite prism until they reach a ductile organic matrix where most of them are stopped. The obtained results confirm a strong anisotropy of both crack propagation and the mechanical strength caused by the formation of the prismatic structure in the outer layer of P. margaritifera shell.

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Laboratory Computed X-Ray Tomography – A Nondestructive Technique for 3D Microstructure Analyis of Materials

Cited by 21 publications

References 15 publications

Chunky Graphite in Ferritic Spheroidal Graphite Cast Iron: Formation, Prevention, Characterization, Impact on Properties: An Overview

Chunky Graphite in Ferritic Spheroidal Graphite Cast Iron: Formation, Prevention, Characterization, Impact on Properties: An Overview

Morphology and Mechanical Properties of Fossil Diatom Frustules from Genera of Ellerbeckia and Melosira

Anisotropy of Mechanical Properties of Pinctada margaritifera Mollusk Shell

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