TY - CONF A1 - Kupsch, Andreas A1 - Trappe, Volker A1 - Nielow, D. A1 - Schumacher, David A1 - Lange, A. A1 - Hentschel, M.P. A1 - Redmer, Bernhard A1 - Ewert, U. A1 - Bruno, Giovanni T1 - X-ray laminographic inspection of sandwich shell segments for wind turbine rotor blades N2 - 3D structural investigations are described by X-ray laminography studies of sandwich shell segments, made of a PVC foam core, covered by non-crimp fabric glass fibre composite lay-ups processed by vacuum assisted resin infusion of epoxy. The specific scope of this study is to image transversal flaws within the foam core (joints) and of single ply overlaps. Test flaws were purposely implemented in order to simulate typical failure under cyclic load. In a dedicated test rig for shell structures, the flaw evolution/propagation is monitored by thermography and optical 3D inspection of deformation. Due to the unfavourable preconditions for classical computed tomography as of large aspect ratio, the samples were investigated by coplanar translational laminography. Its limited range of observation angles of ± 45°, results in anisotropic artefacts about the normal to the sample surface, but the typical flaws are well visualized in the as-prepared state, in a state of early damage, and in the repaired state. T2 - 12th European conference on Non-Destructive Testing CY - Gothenburg, Sweden DA - 11.06.2018 KW - X-ray laminography KW - Wind turbine KW - Rotor blade PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-453931 SN - 978-91-639-6217-2 SP - 1 EP - 8 AN - OPUS4-45393 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Serrano, Itziar A1 - Müller, Bernd A1 - Kupsch, Andreas A1 - Bruno, Giovanni A1 - Laquai, Rene' T1 - X-ray refractio techniques non-destructively quantify and classify defects in am materials N2 - X-ray refraction is analogous to visible light deflection by matter; it occurs at boundaries between different media. The main difference between visible light and X-rays is that in the latter case deflection angles are very small, from a few seconds to a few minutes of arc (i.e., the refraction index n is near to 1). Importantly, deflection of X-rays is also sensitive to the orientation of the object boundaries. These features make X-ray refraction techniques extremely suitable to a) detect defects such as pores and microcracks and quantify their densities in bulk (not too heavy) materials, and b) evaluate porosity and particle properties such as orientation, size, and spatial distribution (by mapping). While X-ray refraction techniques cannot in general image single defects, they can detect objects with size above a few wavelengths of the radiation. Such techniques, especially at the Synchrotron BESSY II, Berlin, Germany, can be used in-situ, i.e. when the specimen is subjected to temperatures or external loads. The use of X-ray refraction analysis yields quantitative information, which can be directly input in kinetics, mechanical and damage models. We hereby show the application of non-destructive X-ray refraction radiography (SXRR, 2D mapping also called topography) to problems in additive manufacturing: 1) Porosity analysis in PBF-LM-Ti64. Through the use of SXRR, we could not only map the (very sparse) porosity distribution between the layers and quantify it, but also classify, and thereby separate, the filled porosity (unmolten powder) from the keyhole and gas pores (Figure 1). 2) In-situ heat treatment of laser powder bed fusion PBF-LM-AlSi10Mg to monitor microstructure and porosity evolution as a function of temperature (Figure 2). By means of SXRR we indirectly observed the initial eutectic Si network break down into larger particles as a function of increasing temperature. We also could detect the thermally induced porosity (TIP). Such changes in the Si-phase morphology upon heating is currently only possible using scanning electron microscopy, but with a much smaller field-of-view. SXRR also allows observing the growth of some individual pores, usually studied via X-ray computed tomography, but again on much smaller fields-of-view. Our results show the great potential of in-situ SXRR as a tool to gain in-depth knowledge of the defect distribution and the susceptibility of any material to thermally induced damage and/or microstructure evolution over statistically relevant volumes. T2 - AAMS 2023 CY - Madrid, Spain DA - 27.09.2023 KW - X-ray Refaction radiography KW - Defects KW - Large Scale Facilities KW - Computed tomography PY - 2023 AN - OPUS4-58508 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni A1 - Kupsch, Andreas A1 - Mueller, Bernd R. A1 - Lange, Axel T1 - X-ray refraction 2D and 3D techniques N2 - X-ray refraction techniques represent a very promising, yet not so wide-spread, set of X-ray techniques based on refraction effects. They allow determining internal specific surface (surface per unit volume) in a non-destructive fashion, position and orientation sensitive, and with nanometric detectability. While they are limited by the X-ray absorption of the material under investigation, we demonstrate showcases of ceramics and composite materials, where understanding of microstructural features could be achieved in a way unrivalled even by high-resolution techniques such as electron microscopy or computed tomography. T2 - ICTMS 2017 CY - Lund, Sweden DA - 26.06.2017 KW - X-ray refraction KW - Composites KW - Damage KW - Cracks KW - Cearmics PY - 2017 AN - OPUS4-41042 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Laquai, René A1 - Müller, Bernd R. A1 - Kasperovich, G. A1 - Haubrich, J. A1 - Requena, G. A1 - Bruno, Giovanni T1 - X-ray refraction distinguishes unprocessed powder from empty pores in selective laser melting Ti-6Al-4V N2 - For the first time, X-ray refraction techniques are proven for the identification of void formation in Ti-6Al-4V parts produced by selective laser melting. The topology and volume fraction of pores are measured in samples produced with different laser energy density. Unique X-ray refraction methods identify different kinds of defects, characteristic to the regions below and above the Optimum laser energy density, namely unprocessed powder (unmolten powder particles, balling effect, and Fusion defects) from empty keyhole pores. Furthermore, it is possible to detect small inhomogeneities (voids or cracks) with sizes below the spatial resolution of optical microscopy and X-ray computed tomography. KW - Additive manufacturing KW - X-ray refraction KW - Microscopy KW - X-ray computed tomography KW - Porosity PY - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-434041 SN - 2166-3831 VL - 6 IS - 2 SP - 130 EP - 135 PB - Taylor & Francis Group CY - London, UK AN - OPUS4-43404 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Bernd R. A1 - Léonard, Fabien A1 - Lange, Axel A1 - Kupsch, Andreas A1 - Bruno, Giovanni T1 - X-ray refraction techniques for fast, high-resolution microstructure characterization and non-destructive testing of lightweight composites N2 - X-ray refraction is based on optical deflection of X-rays, similar to the well-known small angle X-ray scattering, but hundreds of times more intense, thus enabling shorter measurement time. We show that X-ray refraction techniques are suitable for the detection of pores, cracks, and in general defects. Indeed, the deflected X-ray intensity is directly proportional to the internal specific surface (i.e., surface per unit volume) of the objects. Although single defects cannot be imaged, the presence of populations of those defects can be detected even if the defects have sizes in the nanometer range.We present several applications of X-ray refraction techniques to composite materials:- To visualize macro and microcracks in Ti-SiC metal matrix composites (MMC);- To correlate fatigue damage (fibre de-bonding) of carbon fibre reinforced plastics (CFRP) to X-ray refraction intensity;- To quantify the impact damage by spatially resolved single fibre de-bonding fraction as a function of impact energy in CFRP laminates.An example of classic high-resolution computer tomography of an impact-damaged CFRP will also be presented, as a benchmark to the present state-of-the-art imaging capabilities. It will be shown that while (absorption) tomography can well visualize and quantify delamination, X-ray refraction techniques directly yield (spatially resolved) quantitative information about fibre de-bonding, inaccessible to absorption tomography. KW - X-ray KW - Synchrotron radiation KW - Refraction KW - Metal matrix composites KW - Delamination KW - Fiber de-bonding PY - 2015 U6 - https://doi.org/10.4028/www.scientific.net/MSF.825-826.814 SN - 0255-5476 VL - 825-826 SP - 814 EP - 821 PB - Trans Tech Publications CY - Aedermannsdorf, Switzerland AN - OPUS4-33265 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni A1 - Serrano Munoz, Itziar A1 - Kupsch, Andreas A1 - Müller, Bernd R. T1 - X-Ray-Refraction-Imaging-Techniques high-resolution microstructural characterization N2 - X-ray refraction is analogous to visible light deflection by matter; it occurs at boundaries between different media. The main difference between visible light and X-rays is that in the latter case deflection angles are very small, from a few seconds to a few minutes of arc (i.e., the refraction index n is near to 1). Trivially but importantly, deflection of X-rays is also sensitive to the orientation of the object boundaries. These features make X-ray refraction techniques extremely suitable to a) detect defects such as pores and microcracks and quantify their densities in bulk (not too heavy) materials, and b) evaluate porosity and particle properties such as orientation, size, and spatial distribution (by mapping). While X-ray refraction techniques cannot in general image single defects, their detectability is simply limited by the wavelength of the radiation. We thereby show the application of X-ray refraction 2D mapping (topography) and tomography to different sorts of problems in materials science and technology: 1) Sintering of SiC green bodies; 2) Porosity analysis in additively manufactured alloys; 3) Fiber de-bonding in metal and polymer matrix composites. Such techniques, especially at the Synchrotron BESSY II, Berlin, Germany, can be used in-situ, i.e. when the specimen is subjected to temperatures or external loads. Applications of in-situ X-ray refraction radiography on aluminum alloys and composites are also shown. The use of X-ray refraction analysis yields quantitative information, which can be directly input in kinetics, mechanical and damage models. T2 - ICT 2023 CY - Fürth, Germany DA - 27.02.2023 KW - X-ray refraction KW - Composites KW - In-situ KW - Additive Manufacturing KW - Sintering KW - Ceramics PY - 2023 AN - OPUS4-57200 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni A1 - Gollwitzer, Christian A1 - Lange, A. A1 - Onel, Yener A1 - Cooper, R. C. A1 - Watkins, T.R. A1 - Shyam, A. T1 - XCT discloses the Impact of Machining on Mechanical Properties of Diesel Particulate Filter Materials N2 - Microstructural changes in porous cordierite for diesel particulate filter applications caused by machining were characterized using microtensile testing and X-ray computed tomography (XCT). Young’s modulus was determined on ~215-380 m thick machined samples by digital image correlation. Results show a decrease of Young’s modulus due to machining of the thin samples. Explanation of this phenomenon was provided by XCT: the presence of debris due to machining and the variation of porosity due to removal of the outer layers were quantified and correlated with the introduction of further microcracking. T2 - ICT Conference 2018 CY - Wels, Austria DA - 06.02.2018 KW - Diesel Particulate Filter Materials KW - Mechanical Properties PY - 2018 AN - OPUS4-44778 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bruno, Giovanni A1 - Onel, Yener A1 - Cooper, R. C. A1 - Lange, A. A1 - Watkins, T. R. A1 - Shyam, A. T1 - Young's modulus and Poisson's ratio changes due to machining in porous microcracked cordierite N2 - Microstructural changes in porous cordierite caused by machining were characterized using microtensile testing, X-ray computed tomography, and scanning electron microscopy. Young's moduli and Poisson's ratios were determined on similar to 215- to 380-mu m-thick machined samples by combining digital image correlation and microtensile loading. The results provide evidence for an increase in microcrack density and decrease of Young's modulus due to machining of the thin samples extracted from diesel particulate filter honeycombs. This result is in contrast to the known effect of machining on the strength distribution of bulk, monolithic ceramics. KW - Stress KW - Beta-Eucryptite KW - Brittle materials KW - Ceramic materials KW - Thermal-Expansion KW - Fracture-Toughness KW - Composite materials KW - Differential scheme KW - Elastic-moduli KW - Representative volume element PY - 2016 U6 - https://doi.org/10.1007/s10853-016-0209-9 SN - 0022-2461 VL - 51 IS - 21 SP - 9749 EP - 9760 PB - Springer, NY, USA AN - OPUS4-37867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -