Micro-Diagnostics: X-ray and Synchrotron Techniques

Müller, Bernd R.; Hentschel, Manfred P.

doi:10.1007/978-3-642-25850-3_14

Cited by 9 publications

(4 citation statements)

References 19 publications

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“…X-ray refraction techniques were introduced a couple of decades ago [18] and have been successfully used for both material characterization and non-destructive testing [19]. X-ray refraction techniques are used to obtain the amount of the relative internal specific surface (i.e., surface per unit volume, relative to a reference state) of a specimen, and are therefore beneficial in the investigation of defects such as cracks and pores within ceramic components.…”

Section: Methodsmentioning

confidence: 99%

Evolution of Thermal Microcracking in Refractory ZrO2-SiO2 after Application of External Loads at High Temperatures

et al. 2019

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Zirconia-based cast refractories are widely used for glass furnace applications. Since they have to withstand harsh chemical as well as thermo-mechanical environments, internal stresses and microcracking are often present in such materials under operating conditions (sometimes in excess of 1700 °C). We studied the evolution of thermal (CTE) and mechanical (Young’s modulus) properties as a function of temperature in a fused-cast refractory containing 94 wt.% of monoclinic ZrO2 and 6 wt.% of a silicate glassy phase. With the aid of X-ray refraction techniques (yielding the internal specific surface in materials), we also monitored the evolution of microcracking as a function of thermal cycles (crossing the martensitic phase transformation around 1000 °C) under externally applied stress. We found that external compressive stress leads to a strong decrease of the internal surface per unit volume, but a tensile load has a similar (though not so strong) effect. In agreement with existing literature on -eucryptite microcracked ceramics, we could explain these phenomena by microcrack closure in the load direction in the compression case, and by microcrack propagation (rather than microcrack nucleation) under tensile conditions.

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Section: Methodsmentioning

confidence: 99%

Evolution of Thermal Microcracking in Refractory ZrO2-SiO2 after Application of External Loads at High Temperatures

et al. 2019

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“…X‐ray refraction techniques were introduced a couple of decades ago and have been successfully used for both materials characterization and non‐destructive testing . Those techniques are used to obtain the amount of the relative internal specific surface (ie, surface per unit volume, relative to a reference state) of a specimen, and therefore effective in the investigation of defects within ceramic components such as cracks and pores.…”

Section: Introductionmentioning

confidence: 99%

Evolution of porosity, crack density, and CMAS penetration in thermal barrier coatings subjected to burner rig testing

et al. 2019

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Degradation of thermal barrier coatings (TBCs) in gas‐turbine engines due to calcium–magnesium–aluminosilicate (CMAS) glassy deposits from various sources has been a persistent issue since many years. In this study, state of the art electron microscopy was correlated with X‐ray refraction techniques to elucidate the intrusion of CMAS into the porous structure of atmospheric plasma sprayed (APS) TBCs and the formation and growth of cracks under thermal cycling in a burner rig. Results indicate that the sparse nature of the infiltration as well as kinetics in the burner rig are majorly influenced by the wetting behavior of the CMAS. Despite the obvious attack of CMAS on grain boundaries, the interaction of yttria‐stabilized zirconia (YSZ) with intruded CMAS has no immediate impact on structure and density of internal surfaces. At a later stage the formation of horizontal cracks is observed in a wider zone of the TBC layer.

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“…X-ray refraction techniques [20][21][22] are radiographic and tomographic techniques that combine a large field of view (several millimeters) with an exceptional detectability of small defects (whose size was estimated to lie below 1 nm). 23 While their spatial resolution is limited by the beam size in the laboratory (typically 50 by 1,000 μm), and by the camera pixel size at a synchrotron (typically 1-5 μm), they are able to detect nanometric objects.…”

Section: Introductionmentioning

confidence: 99%

Classification of Defect Types in SLM Ti-6Al-V4 by X-ray Refraction Topography

Laquai

Müller

Kasperovich

et al. 2020

Materials Performance and Characterization

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Porosity in additively manufactured materials, such as laser powder bed fusion Ti-Al6-V4, can play an important role in their mechanical performance. Not only the total porosity but also the shape/morphology of the individual pores need to be considered. Therefore, it is necessary to determine the distributions of different defect types (especially fusing defects and keyhole pores) and their dependence on process parameters. We show that synchrotron X-ray refraction radiography allows analysis of large samples (up to several millimeters) without compromising the detectability of submicrometer defects. Correspondingly, a classification tool is introduced that is able to quantitatively distinguish defects such as keyhole pores and binding defects with a confidence level of 94 %, even when the shape cannot be discerned because of limited spatial resolution.

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Micro-Diagnostics: X-ray and Synchrotron Techniques

Cited by 9 publications

References 19 publications

Evolution of Thermal Microcracking in Refractory ZrO2-SiO2 after Application of External Loads at High Temperatures

Evolution of Thermal Microcracking in Refractory ZrO2-SiO2 after Application of External Loads at High Temperatures

Evolution of porosity, crack density, and CMAS penetration in thermal barrier coatings subjected to burner rig testing

Classification of Defect Types in SLM Ti-6Al-V4 by X-ray Refraction Topography

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