TY - CONF A1 - Stegemann, Robert T1 - Evaluation magneto-mechanischer Effekte in hochauflösenden Magnetfeldmessungen durch Neutronendiffraktion N2 - Die mechanische Spannung ist ein maßgeblicher Parameter ferromagnetischer Materialien. Wird ein solches Material unter die Curie Temperatur abgekühlt, zerfällt es spontan in nahezu selbstgesättigte magnetische Domänen. Diese Magnetisierung führt gleichzeitig zu einer Verformung der mit ihr gekoppelten Kristallgitter. Ein Effekt der auch reziprok gilt: wird die Gitterverformung durch eine Spannung behindert ändert sich zwangsweise der magnetische Zustand. Man kann annehmen, dass zwischen unterschiedlichen, für sich aber homogen verspannten Werkstoffbereichen, lokale magnetische Streufelder auftreten, weil magneto-mechanische Effekte eine Inkompatibilität der Domänenstruktur induzieren. Bekanntlich bilden sich Spannungsgradienten nach Schweißprozessen durch ungleichmäßigen Wärmeeintrag, thermischer Dehnung, und unterschiedlichen Abkühlraten aus. Unter dieser Prämisse untersuchen wir Wolfram-Inertgas geschweißte Blindnahtproben (250x100x4,8 mm^3) aus einem hypereutektoiden Baustahl. Der Spannungszustand der Proben wurde anhand von Neutronendiffraktometrie (ND) am Instrument E3 am Reaktor BERII (Helmholzzentrum Berlin, HZB) charakterisiert. ND ist ein Referenzverfahren für die quantitative Bestimmung von elastischen Dehnungen in kristallinen Materialien, deren Gitter selbst der Messmaßstab ist. Die Auswertung zeigt hohe Längsspannungen mit lokalen Maxima in Größenordnung von 600 MPa, die von umgebenen Druckspannungszonen kompensiert werden. Zur Detektion der magnetischen Kleinststreufelder verwenden wir speziell designte GMR-Sensorik (GMR - Giant Magneto Resistance), die aufgrund der geringen Größe ihrer aktiven Sensorelemente hohe Ortsauflösung mit Sensitivität vereint. Die Visualisierung der Messergebnisse lässt eine klare magnetische Mikrostruktur der Schweißnähte erkennen, in der die Streufelder lateral in Größenordnung des Erdmagnetfeldes variieren (~50 µT). Wir zeigen durch einen Vergleich beider Messverfahren, dass lokale magnetische Streufeldmaxima in hohem Maße mit den Spannungsgradienten übereinstimmen. T2 - DGZfP-Jahrestagung CY - Koblenz, Germany DA - 22.05.2017 KW - WIG-Blindschweißnaht KW - GMR-Sensorik KW - Neutronendiffraktion KW - Eigenspannungen PY - 2017 AN - OPUS4-40370 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn T1 - Tailoring the spring constant of ceramic helical compression springs N2 - Ceramic springs combine attractive properties for applications in machinery, metrology, and sensor technology. They are electrically insulating, non-magnetic, provide a linear stress-strain behavior, and are stable at high temperatures and in corrosive environments. Generally, the precise dimensioning of a ceramic spring with respect to the spring constant is challenging. Different models are described, but many of these calculations do not match the actual spring properties. We demonstrate a reliable approach for the dimensioning and manufacturing of helical compression springs with a rectangular winding cross-section. Based on the German standard DIN 2090, which is referring to metallic springs, the spring constant can be calculated based on shear modulus, diameter, height, widths, and number of windings. Different ceramic springs were produced by milling of sintered hollow cylinders of zirconia, alumina and silicon nitride. The experimental spring constants are in very good agreement with the calculated values. Spring constants of zirconia springs were varied over three orders of magnitude between 0.02 N/mm and 5 N/mm by purposeful adaption of the spring geometry. The combination of dimensioning based on DIN 2090 and precise hard machining offers a reliable technology for the fabrication of tailored ceramic springs for special applications. T2 - 45th International Conference and Exhibition on Advanced Ceramics and Composites (ICACC 2021) CY - Online meeting DA - 08.02.2021 KW - Ceramics KW - Hard machining KW - Spring constant PY - 2021 AN - OPUS4-52136 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kardjilov, N. T1 - Quantification of hydrogen in metals applying neutron imaging techniques N2 - Hydrogen interaction with metals is well known to have severe detrimental effects on their mechanical properties. The use of modern high-strength steels, which are attractive to improve fuel economy by reducing weight as well as candidates for H storage cylinders and other components, is currently being severely limited by the fact that the presence of H can cause embrittlement of the material. In addition to steel, several other metals and alloys used in the nuclear industry, like Ti and Zr, are susceptible to H degradation through hydride formation and subsequent cracking. Microstructure-specific H mapping has been recognized as the most important challenge on the pathway towards a better understanding of the nature of H embrittlement in metallic alloys as well as the development of H storage solutions based on metal hydrides. Unfortunately, the characterization of H interactions with metals is an extremely challenging task and neutron-based techniques are of exceptional importance in this matter because – contrary to X-rays and electrons – thermal and cold neutrons interact strongly with the H nuclei, while the neutron beam is only weakly attenuated by the relevant metallic materials. Therefore, hydrogen distributions can be measured and quantified even in 3D by tomographic methods. Here we present several neutron imaging investigations of embrittlement and cracking in Fe and Zr based metal alloys and optimization studies of hydrogen storage systems containing metal hydrides as an active substance. The advantages and the limitations of the experimental methods as well as the attempts for hydrogen quantification will be discussed in detail. T2 - M&M 2022 Annual Meeting (Microscopy & Microanalysis) CY - Portland, Oregon, USA DA - 31.07.2022 KW - Neutron imaging techniques KW - Hydrogen in metals PY - 2022 DO - https://doi.org/10.1017/S1431927622006638 AN - OPUS4-55716 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn T1 - Preparation of a Primary Reference Material for Magnesium Isotope Ratio Determination at Highest Metrological Level, and Redetermination of the Magnesium Atomic Weight T2 - 46. Jahrestagung der Deutschen Gesellschaft für Massenspektrometrie CY - Berlin, Germany DA - 2013-03-10 PY - 2013 N1 - Geburtsname von Mieller, Björn: Brandt, B. - Birth name of Mieller, Björn: Brandt, B. AN - OPUS4-30362 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Markötter, Henning T1 - In situ tomographic imaging with hard x rays at Bamline (BESSY II) N2 - The BAMline at the synchrotron X-ray source BESSY II (Berlin, Germany) is supporting researchers especially in materials science [1]. As a non-destructive characterization method, synchrotron X-ray imaging, especially tomography (SXCT) with hard X-Rays, plays an important role in structural 3D characterization. The imaging capabilities allow for in-situ and operando experiments. In this presentation the equipment, data handling pipeline as well as various examples from material science are presented. In series-connected lithium-ion cells are susceptible to an electrical safety hazard called over-discharge. Here the behavior of copper dissolution and deposition during over-discharge is presented, which leads to irreversible loss of capacity and internal short circuits. The concentration of dissolved and deposited copper is quantified. Also, a non-uniform distribution pattern of copper deposition on the cathode is shown. The second example deals with an Al alloy 7017 customized for a 3d-printing process by means of laser-based powder bed fusion (PBF-LB) technique. These advanced alloys have a significantly higher modulus of elasticity than conventional Al alloys, making them attractive for applications requiring high stiffness. SXCT during In-situ tensile tests confirmed that fracture initiation strongly depends on defects created during printing. However, the cracks are deflected from decohesion around inclusions/precipitates embedded in the Al matrix, increasing ductility. Low temperature cofired ceramic (LTCC) multilayer housings offer 3D-circuits for a wide range of applications in telecommunications, microsystems and sensor technology. Such housings are produced by combining structured and metallized ceramic layers using tape-casting and multilayer technology. The characterization of the integrity, deformation, defects, and positioning of the internal metal features was carried out using in-situ SXCT at up to 950°C. A high-precision nail penetration tool was developed to characterize the mechanically induced thermal runaway (TR) of lithium-ion battery (LIB) cells in a dynamic temperature range down to -190 °C. To investigate safety-specific low-temperature transport conditions, the damaged cells were tomographically imaged during thawing. T2 - ICTMS - International Conference on Materials and Structures 2024 CY - Cape Town, South Africa DA - 01.07.2024 KW - Synchrotron radiation KW - X-ray tomography KW - Li-ion battery PY - 2024 AN - OPUS4-60658 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Mente, Tobias A1 - Markötter, Henning A1 - Al-Falahat, M. A1 - Kardjilov, N. T1 - Neutron Bragg edge imaging for in situ mapping of crystallographic phase-transformations and of temperature distributions during GTAW of supermartensitic stainless steel N2 - In Neutron-Bragg-Edge Imaging (NBEI) experiments, we studied the phase transition during butt-welding of supermartensitic steel plates. Gas tungsten arc welding (GTAW) was used with a motorized torch allowing for automated weldments. The austenitization in the heat affected zone (HAZ) underneath the welding head could be clearly visualized at λ = 0.39 nm, a wavelength smaller than the Bragg edge wavelengths of both austenite and martensite. Also, the re-transformation into the martensitic phase upon cooling was detected. However, we observed an unexpected additional change in transmission at λ = 0.44 nm that is a wavelength larger than the wavelength of the Bragg edges of both the martensitic and austenitic phases. We attribute this change to the Deybe-Waller-Factor that describes the temperature dependence of coherent scattering at a crystal lattice. The observed two-dimensional attenuation map corresponds well with a temperature distribution modelling by software macros in ANSYS. Here, the absolute temperature values could be achieved by calibrating the modelled attenuation with help of a thermocouple placed at the steel plate. This allows in return for a direct two-dimensional temperature reading based on the Debye-Waller-relation between neutron attenuation and sample temperature. T2 - ITMNR-9 CY - Buenos Aires, Argentina DA - 12.10.2022 KW - Debye-Waller-Faktor PY - 2023 AN - OPUS4-58627 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn T1 - Synthesis and testing of beta aluminate sodium electrolyte (BASE) for sodium ion battery development N2 - Sodium beta aluminate, or beta aluminate solid electrolyte (BASE), is an established material for tubular electrolytes in NaNiCl2 and NaS batteries, and a promising candidate for planar electrolytes in safe all solid-state batteries. The synthesis of BASE with high ionic conductivity is still challenging due to process dependent formation of different phases in the sintered material. However, to drive forward the development of active materials for all solid-state sodium ion batteries, the fabrication of solid electrolyte specimens with reproducible performance is required. With respect to the various testing scenarios in the field, for example cell assembly for cycling, electrolyte parts are needed in various shapes, sizes, and thicknesses in the lab. Different ceramic shaping technologies can be applied to produce such geometries, including pressing combined with green or hard machining, or tape casting combined with punching. Typically, different shaping technologies require adapted pre-treatment of the powder which might affect the resulting properties and thus need to be investigated. In this contribution, starting from the raw materials mixture, aspects of milling, drying, aqueous slurry preparation for tape casting, and firing are discussed with respect to particle size distribution, stability, energy consumption and resulting material properties. Finally, the fabrication and cyclic testing of Na/electrolyte/Na coin cells is presented. T2 - XIXth Conference of the European Ceramic Society / SBS6 International Sodium Battery Symposium CY - Dresden, Germany DA - 01.09.2025 KW - Ceramics KW - Beta aluminate solid electrolyte KW - Sodium ion battery PY - 2025 AN - OPUS4-64054 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Laquai, René T1 - 3D crack analysis in hydrogen charged lean duplex steel with refraction CT N2 - Hydrogen in metals can cause a degradation of the mechanical properties, the so-called hydrogen embrittlement. In combination with internal stresses, hydrogen assisted cracking (HAC) can occur. This phenomenon is not completely understood yet. To better characterise the cracking behaviour, it is important to gain information about the evolution of the 3D crack network. For this purpose samples of lean duplex stainless steel were loaded with hydrogen by means of electrochemical charging and investigated by means of synchrotron refraction CT and SEM fractography after uniaxial tensile loading. Synchrotron refraction CT is an analyser-based imaging (ABI) technique. It uses a Si (111) single crystal as analyser, which is placed into the beam path between sample and detector. According to Bragg’s law only incident x-rays within a narrow range around the Bragg-angle are diffracted from the analyser into the detector. Hence, the analyser acts as an angular filter for the transmitted beam. This filtering allows to turn the refraction and scattering of x-rays into image contrast. Refraction occurs at all interfaces, where the density of the material changes and is more sensitive to density changes than the attenuation. Therefore, it is possible to detect smaller cracks than with classical x-ray imaging techniques, like CT, with comparable spacial resolution. It also visualises the 3D structure of the cracks and gains quantitative information about their morphology and distribution. Since cracks introduced by HAC are usually very small and have a small opening displacement, synchrotron refraction CT is expected to be well suited for imaging this cracking mechanism and can be a valuable tool to characterise the formation and the evolution of a 3D crack network. T2 - WCNDT 20016 CY - München, Germany DA - 13.06.2016 KW - X-ray refraction KW - Hydrogen assisted cracking KW - Computed tomography KW - Duplex stainless steel PY - 2016 AN - OPUS4-36616 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Computed tomography of LBM produced In625 lattices: Integrity analysis from powder particles to structures N2 - We investigated lattice structure manufactured by laser beam melting with computed tomography on difference scales, such as powder scale, strut scale and lattice scale. The raw powder has been evaluated by means of synchrotron computed tomography (CT) at the BAM-Line (HZB Bessy II, Berlin). Therefore, the particle size distribution and even the pore size distribution was investigated and compared with results received by the producer by means of sieving. Studies with laboratory X-ray CT of porosity and roughness of manufactured struts in dependence of the build angle exhibited the tendency that elongated pores appear solely in a certain range near the edge. The integrity and load-bearing capacity of a lattice structure was investigated by means of in-situ CT during compression. The lattice structure was compressed by 10 % in height with an applied maximum force of 5 kN. We applied digital volume correlation algorithm on volumes of different load steps to quantifies the displacement within the structure. T2 - Metallographie-Tagung 2018 CY - Leoben, Austria DA - 19.09.2018 KW - Additive manufacturing KW - Laser beam melting KW - Computed tomography KW - Lattice structures KW - In-situ CT KW - Porosity KW - Roughness PY - 2018 AN - OPUS4-45998 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas T1 - Wire arc additive manufacturing of high strength AL-MG-SI alloys N2 - Gas metal arc-based direct energy deposition (DED) additive manufacturing technologies hold significant promise for producing large-scale metal components. However, determining optimal process parameters to achieve the desired near-net shape design and mechanical performance is a complex challenge due to the intricate interplay between process parameters and material properties. This presentation highlights the use of a newly developed solid welding wire doped with TiB to improve grain refinement in metals deposited via DED-Arc for high-strength precipitation-hardening AlMgSi aluminum alloys. This wire stems from our initial metallurgical investigations into grain refinement in aluminum weld metals. The research emphasizes the relationship between process parameters and component quality, aiming to uncover the mechanisms that influence performance. This is essential for establishing a reliable range of parameters that meet quality standards, many of which are derived from traditional welding practices. Component quality was assessed by studying pore size, pore distribution, and grain morphology. To further enhance the mechanical properties of the deposited material, post-weld heat treatments—including solution treatment, quenching, and artificial aging—were applied. The study also explores how different heat treatment strategies affect the final mechanical properties. To validate the feasibility of 3D printing high-strength aluminum alloys, a more complex demonstrator component was fabricated. The results demonstrate that DED-Arc technology can produce large aluminum parts with a quality comparable to subtractive manufacturing techniques. Furthermore, the entire additive manufacturing workflow has been digitally integrated, enabling full traceability of all key process steps. This digital integration is critical for ensuring reliable quality assessments of the finished components. T2 - 77th IIW Annual Assembly and International Conference Joint Meeting of C-I, C-IV, and C-XII CY - Rhodos, Greece DA - 07.07.2024 KW - DED-Arc KW - High-strength aluminium alloys KW - Porosity assessment KW - Component testing KW - CT-analyses PY - 2024 AN - OPUS4-62014 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Stargardt, Patrick T1 - Bulk vs thermal sprayed alumina for insulation applications: A comparison of electrical and dielectrical properties N2 - Additive manufacturing (AM) processes are opening new design possibilities for large scale electrical devices such as power generators. Conventional manufacturing methods use copper rods which are wrapped, vacuum impregnated, bend and welded. These processes are labor-intensive and time-consuming. The introduction of AM methods for manufacturing the copper conductor and electrical insulation can reduce the size of the generator head, the most complex part of the generator. In this study, the electrical and dielectrical properties of additively deposited ceramic layers are investigated and compared with the properties of conventionally fabricated bulk ceramics. The ceramic layers are thermally deposited by atmospheric plasma spraying of a commercially available alumina powder. Bulk ceramics are fabricated by dry pressing and sintering of the same powder. Microstructure and porosity were analyzed by scanning electron microscopy (SEM). Electrical and dielectrical properties such as DC resistance, dielectric strength, dielectric loss, and relative permittivity were determined according to the standards. The microstructures of sprayed and sintered alumina show significant differences with respect to grain form and porosity. The density of the bulk ceramic is lower than the density of the sprayed layer due to the coarse particle size (d50 = 33 μm). Therefore, data from dense samples of the same chemical composition but lower particle size alumina powder were used for comparison. T2 - Keramik 2022 CY - Online meeting DA - 07.03.2022 KW - High Voltage Insulation KW - Thermal Spray KW - Dielectric Spectroscopy KW - Atmospheric Plasma Spraying PY - 2022 AN - OPUS4-54446 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schröder, Jakob T1 - Laser Powder Bed Fusion: Fundamentals of Diffraction-Based Residual Stress Determination N2 - The general term additive manufacturing (AM) encompasses processes that enable the production of parts in a single manufacturing step. Among these, laser powder bed fusion (PBF-LB) is one of the most commonly used to produce metal components. In essence, a laser locally melts powder particles in a powder bed layer-by-layer to incrementally build a part. As a result, this process offers immense manufacturing flexibility and superior geometric design capabilities compared to conventional processes. However, these advantages come at a cost: the localized processing inevitably induces large thermal gradients, resulting in the formation of large thermal stress during manufacturing. In the best case, residual stress remains in the final parts produced as a footprint of this thermal stress. Since residual stress is well known to exacerbate the structural integrity of components, their assessment is important in two respects. First, to optimize process parameter to minimize residual stress magnitudes. Second, to study their effect on the structural integrity of components (e.g., validation of numerical models). Therefore, a reliable experimental assessment of residual stress is an important factor for the successful application of PBF-LB. In this context, diffraction-based techniques allow the non-destructive characterization of the residual stress. In essence, lattice strain is calculated from interplanar distances by application of Braggs law. From the known lattice strain, macroscopic stress can be determined using Hooke’s law. To allow the accurate assessment of the residual stress distribution by such methods, a couple of challenges in regard of the characteristic PBF-LB microstructures need to be overcome. This presentation highlights some of the challenges regarding the accurate assessment of residual stress in PBF-LB on the example of the Nickel-based alloy Inconel 718. The most significant influencing factors are the use of the correct diffraction elastic constants, the choice of the stress-free reference, and the consideration of the crystallographic texture. Further, it is shown that laboratory X-ray diffraction methods characterizing residual stress at the surface are biased by the inherent surface roughness. Overall, the impact of the characteristic microstructure is most significant for the selection of the correct diffraction elastic constants. In view of the localized melting and solidification, no significant gradients of the stress-free reference are observed, even though the cell-like solidification sub-structure is known to be heterogeneous on the micro-scale. T2 - 4th Symposium on Materials and Additive Manufacturing CY - Berlin, Germany DA - 12.06.2024 KW - Additive Manufacturing KW - Residual Stress KW - Electron Backscatter Diffraction KW - Laser Powder Bed Fusion PY - 2024 AN - OPUS4-60294 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Characterization of Cordierite DPFs by means of Synchrotron, Lab, and Neutron Techniques T2 - Symposium Zerstörungsfreie Materialcharakterisierung CY - Berlin, Germany DA - 2013-11-19 PY - 2013 AN - OPUS4-15484 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas T1 - Direkte Röntgenrefraktion an Mikrostrukturen T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 2014-05-26 PY - 2014 AN - OPUS4-30841 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Heckel, Thomas T1 - Zerstörungsfreie Prüfung @ BAM N2 - Die Schwerpunktthemen für die Forschung der BAM im Bereich der zerstörungsfreien Prüfung werden vorgestellt. Es stehen die aktuellen Forschungsprojekte der Fachbereiche 8.1 bis 8.7 der Abteilung 8 und des Arbeitsgebietes Probabilistische Sicherheits- und Zuverlässigkeitsanalysen von Frau Dr. Bertovic sowie der Nachwuchsgruppe von Frau JProf. Dr. Kruschwitz im Vordergrund. T2 - Young Professionals Aerospace 2019 CY - Wildau, Germany DA - 25.11.2019 KW - Zerstörungsfreie Prüfung KW - Sensorik KW - Bauwesen KW - Radiografie KW - Ultraschall KW - Wirbelstrom KW - Computertomografie KW - Faseropische Sensorik KW - Thermografie KW - Human Factors PY - 2019 AN - OPUS4-50013 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Léonard, Fabien T1 - Selective laser melting process optimisation: X-ray and neutron sources for information from powder grains to printed structures N2 - Selective laser melting process optimisation: X-ray and neutron sources for information from powder grains to printed structures T2 - BPWT/BAM Workshop " Innovative Materialien und Qualitätskontrolle für additive Fertigung" CY - Berlin, Germany DA - 12.09.2018 KW - SLS KW - X-ray computed tomography KW - Refraction KW - Neutron diffraction KW - Additive manufacturing KW - Industry 4.0 PY - 2018 AN - OPUS4-45924 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Laquai, René A1 - Schaupp, Thomas A1 - Müller, Bernd R. A1 - Griesche, Axel A1 - Bruno, Giovanni A1 - Kannengießer, Thomas T1 - 3D imaging of hydrogen assisted cracking using analyser-based imaging N2 - To better understand the mechanism of hydrogen assisted cracking (HAC), it is important to investigate the 3D structure of the cracks non-destructively. Since, cracks introduced by HAC are usually very small, conventional x-ray imaging methods often lack the required spatial resolution. However, the detection of those cracks can be enhanced by taking advantage of refraction at interfaces within the sample. To image this refractive deflection we employ analyser based imaging (ABI). In this work we aim at proving the enhanced crack detection of ABI by investigating an alluminum alloy weld. T2 - BESSY User Meeting 2015 CY - Berlin, Germany DA - 09.12.2015 KW - X-ray refraction KW - Synchrotron KW - Analyser-based imaging KW - Hydrogen assisted cracking KW - Welding PY - 2015 AN - OPUS4-38278 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Léonard, Fabien T1 - On nominal-actual comparisons for additive manufacturing applications N2 - Nominal-actual comparisons are routinely performed to compare a manufactured specimen to a reference specimen. X-ray Computed Tomography (CT) has brought a profound change in the way that tolerance verifications are performed in industry, by allowing the inner and outer geometries of an object to be measured, without the need for external access or destructive testing. As a results, CT is increasingly used in additive manufacturing applications, where a nominal-actual comparison performed between the digital model (CAD file), used as an input for the 3D printer, and the CT volume from the printed part, can provide invaluable information as to the accuracy of the printing process. However, the nominal-actual comparison process is somewhat different when applied to additively manufactured specimens by comparison to conventionally manufactured specimens. T2 - 9th Conference on Industrial Computed Tomography CY - Padova, Italy DA - 14.02.2019 KW - Computed tomography KW - X-ray computed tomography KW - Implants PY - 2019 AN - OPUS4-47832 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evans, Alexander T1 - Eigenspannungsrelaxation in additiv gefertigem austenitischem Stahl 316L: Einsatz moderner Beugungsmethoden N2 - In Hinblick auf den austenitischen Stahl AISI 316L erzeugt das pulverbettbasierte selektive Laserstrahlschmelzen, als ein additives Fertigungsverfahren, kristallographisch texturierte und Multiskalige Mikrostruktur. Einerseits können diese Mikrostrukturen zu einer Verbesserung der statischen mechanischen Eigenschaften führen (z. B. zu einer höheren Streckgrenze). Andererseits stehen diesen Verbesserungen der mechanischen Eigenschaften hohe Eigenspannungen gegenüber, die sich nachteilig auf das Ermüdungsverhalten auswirken können. Zur Reduzierung der Eigenspannungen und der daraus resultierenden negativen Auswirkungen auf die Ermüdungseigenschaften, werden Bauteile nach der Herstellung typischerweise wärmebehandelt. In dieser Studie wurde eine niedrige Wärmebehandlungstemperatur von 450°C höher temperierten Behandlungen bei 800 °C und 900 °C gegenübergestellt. Diese Wärmebehandlungstemperaturen bilden die oberen und die untere Grenze ein Spannungsarmglühendes Materials, ohne die prozessinduzierte Mikrostruktur signifikant zu verändern. Zusätzlich bieten diese Temperaturen den Vorteil, dass sie eine übermäßige intergranulare Ausscheidung von Karbiden und TCP-Phasen vermeiden, die zu einer Sensibilisierung des Werkstoffes gegen korrosive Umgebungen führen würden. Die Auswirkungen der Wärmebehandlung auf das Gefüge wurden mittels Rasterelektronenmikroskopie (BSE und EBSD) untersucht. Die Relaxation der Eigenspannungen wurde vor und nach den jeweiligen Wärmebehandlungen bei 800°C und 900°C mittels Neutronenbeugung charakterisiert. Die Ergebnisse zeigen, dass die Proben nach der Wärmebehandlung bei 900 °C nahezu spannungsfrei sind, was mit der Auflösung der zellularen Substruktur korreliert. T2 - AWT-Konferenz Additive Fertigung CY - Bremen, Germany DA - 29.06.2022 KW - Neutronbeugungsverfahren KW - Additive Fertigung KW - L-PBF 316L KW - Eigenspannung PY - 2022 AN - OPUS4-55788 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pittner, Andreas T1 - Additive Manufacturing of High Strength Al-Mg-Si Alloys with DED-Arc N2 - Direct energy deposition additive manufacturing technologies that utilize an electric arc have great potential for generating large volume metal components. However, selecting process parameters that yield the desired near net shape design and requested mechanical component behavior is not a trivial task due to the complex relationship between all process parameters and material characteristics. This presentation exemplifies the application of a newly developed solid welding wire doped with TiB to enhance grain refinement in the deposited metal for additive manufacturing based on DED-Arc of high-strength precipitation hardening AlMgSi-aluminum alloys. It is worth noting that the solid wire is the result of our preliminary metallurgical studies on grain refinement in aluminum weld metal. Consequently, research focuses on the correlation between process parameters and component quality to understand the underlying mechanisms. This is crucial for evaluating a robust process parameter space that yields component quality in line with corresponding standards which are mainly taken from welding technology. Specifically, we examine component quality by analyzing pore size and distribution, as well as grain morphology. To enhance the mechanical properties of the deposited metal, a post-weld heat treatment was conducted, comprising of solution treatment, quenching, and artificial aging. The study also evaluates the effects of various heat treatment strategies on the final mechanical properties of the material. To demonstrate the applicability of 3D metal printing of high-strength aluminium alloys, a more complex demonstrator was created. It has been shown that DED-Arc can produce high-volume aluminium parts with the same quality as the corresponding subtractive processing strategy. Additionally, the entire additive manufacturing chain has been digitally integrated, enabling traceability of all relevant process steps, which is essential for reliable subsequent quality assessment. T2 - 4th Symposium on Materials and Additive Manufacturing - Additive 2024 CY - Berlin, Germany DA - 12.06.2024 KW - DED-Arc KW - High-stength aluminium alloys KW - Grain refinement KW - Quality assurance PY - 2024 AN - OPUS4-60248 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evans, Alexander T1 - Residual Stresses in Additive Manufacturing (L-PBF) N2 - Additive manufacturing (AM) technologies are experiencing an exceedingly rapid growth, driven by their potential through layer wise deposition for transformational improvements of engineering design, leading to efficiency and performance improvements. Laser Powder Bed Fusion (LPBF) is an Additive Manufacturing (AM) method which permits the fabrication of complex structures that cannot otherwise be produced via conventional subtractive manufacturing methods. Nevertheless, the rapid cooling rates associated with this process results in the formation of significant and complex residual stress (RS) fields. A large body of both experimental and simulation research has been dedicated in recent years to the control and mitigation of RS in AM. In order to validate simulations with the end goal of being able to model the residual stress state in AM components and to devise strategies for their reduction during manufacturing, experimental methods need to be able to accurately determine 3D residual stresses fields in complex geometries. Several destructive and non-destructive methods can be used to analyze the RS state, the choice of which depends on the geometry and the information required. Diffraction-based methods using penetrating neutron and synchrotron X-rays at large scale facilities offer the possibility to non-destructively spatially resolve both surface and bulk residual stresses in complex components and track their changes following applied thermal or mechanical loads. This presentation will overview the success stories of using large scale facilities by the BAM for the characterization of residual stresses in additively manufactured metallic alloys. In particular, the study of the influence of process parameters on the residual stress state and the relaxation of these stresses through heat treatment will be presented. However there remains challenges to overcome particularly of the hypotheses underlying the experimental determination of residual stresses, which will be discussed. T2 - 10th International Conference on Mechanical Stress Evaluation by Neutron and Synchrotron Radiation – MECASENS 2021 CY - Prague, Czech Republic DA - 25.11.2021 KW - Residual stress KW - Additive manufacturing KW - Diffraction KW - L-PBF KW - AGIL PY - 2021 AN - OPUS4-54105 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schob, D. T1 - Material and damage behaviour of 3D printed PA12 under cyclic loading N2 - The material and damage behaviour of additively manufactured polyamide 12 (PA12) under dynamic loading was characterized by cyclic tests and microstructure analysis. The results were used to develop a numerical material and damage model. In a recent study, it was shown that the material and damage behaviour of 3D printed PA12 under quasistatic loading is simulated in a realistic way by coupling the material model by Chaboche and the damage model by Gurson-Tvergaard-Needleman (GTN). Using microscopy, X-ray refraction, and computed tomography, a porosity of about 5% was evaluated. These results served as a starting point for the present work. For the dynamic load, both the previously used Chaboche model and the GTN model were extended. Furthermore, the temperature was measured during the experiment and the self-heating effect was observed. Therefore, a temperaturedependent material parameters for the simulation were introduced. Considering the results of mechanical experiments, microstructural investigations, and self-heating effects, a good agreement between Experiment and numerical simulation could be achieved. T2 - VI International Conference on Computational Modeling of Fracture and Failure of Materials and Structures CY - Brunswick, Germany DA - 12.06.2019 KW - Polyamide 12 KW - Selective Laser Sintering (SLS) KW - Viscoplasticity KW - Chaboche model KW - GTN model KW - X-ray refraction KW - Computed tomography PY - 2019 AN - OPUS4-48335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sprengel, Maximilian T1 - The relaxation of macroscopic residual stresses in laser powder bed fused stainless steel 316L N2 - The processing of stainless steel 316L using the additive manufacturing process Laser Powder Bed Fusion (LPBF) can widen its field of application due to a strong increase in Yield strength, without making major compromises on the ductility nor its outstanding corrosion and oxidation properties. Furthermore, improved designs that either reduce the weight or optimise the function of a part can be obtained using LPBF. These benefits are however counterbalanced by the proneness of LPBF to inducing high Residual Stresses (RS) during manufacturing. The characterisation and monitoring of these RS are of paramount importance for the wider acceptance of the LPBF process. This study focuses on the relaxation of the initial macroscopic RS present in an LPBF 316L as-built prism that undergoes various routes of manufacturing steps to achieve different specimen geometries and stress relieving treatments. The RS are determined using Angle-Dispersive (AD) and Time-of-Flight (TOF) neutron diffraction. The results reveal high tensile RS close to the surfaces and compressive RS near the centre of the as-built parts. The reduction in size and change of geometry heavily impact the stress ranges of the remaining RS, with lower stress ranges in cylindrical shaped compared to rectangular shaped specimens. Also, the application of different stress relieving heat treatments showed that heat-treating temperatures above 800 °C are necessary to obtain a strong relaxation in LPBF 316L. T2 - The second European Conference on the Structural Integrity of Additively Manufactured Materials CY - Online meeting DA - 08.09.2021 KW - Residual Stress KW - Additive Manufacturing KW - Neutron Diffraction PY - 2021 AN - OPUS4-53263 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Magkos, Sotirios T1 - Reconstruction of limited-angle projection data with DIRECTT N2 - Direct Iterative Reconstruction of Computed Tomography Trajectories is a fully three-dimensional algorithm that prioritizes the reconstruction of voxels corresponding to dominant trajectories across the projections. T2 - MUMMERING outreach conference CY - Online meeting DA - 10.06.2021 KW - Iteration method KW - X-ray imaging KW - Signal processing KW - Computed tomography PY - 2021 AN - OPUS4-53466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Widjaja, Martinus Putra A1 - Alves, M. A1 - Mavrogordato, M. A1 - Joannes, S. A1 - Bunsell, A. A1 - Mair, Georg W. A1 - Thionnet, A. T1 - Effect of the Time Dependent Loading of Type IV Cylinders Using a Multiscale Model N2 - The Reduced Volume Method (RVM) has been used to evaluate the multiscale fibre break model developed at Mines ParisTech. It allows the model to be assigned only at certain part of the structures without necessarily compromising the final prediction. An attempt to model a simple unidirectional composite structure has also been carried out and gave a satisfying result. This paper deals with the application of the RVM to real scale type IV composite cylinders, where its stacking sequence was evaluated through micro-CT scans conducted with the collaboration of the University of Southampton. Two modelling geometries were evaluated and compared with the corresponding experimental results. T2 - 8th International Conference on Hydrogen Safety (ICHS) CY - Adelaide, Australia DA - 24.09.2019 KW - Fibre break KW - Multiscale modelling KW - Type IV pressure vessel KW - Time dependent loading PY - 2019 SP - ID131 AN - OPUS4-49273 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Bernd R. T1 - Evidence of damage evolution during creep of Al–Mg alloy using synchrotron X-ray refraction N2 - In order to provide further evidence of damage mechanisms predicted by the solid-state transformation creep (SSTC) model, direct observation of damage accumulation during creep of Al–3.85Mg was made using synchrotron X-ray refraction (SXRR). X-ray refraction techniques capture the specific surface (i.e. surface per unit volume) with a field of view comparable to the specimen size but with microscopic sensitivity. A significant rise of the internal specific surface with increasing creep time was observed, providing evidence for the creation of a fine grain substructure, as predicted by the SSTC model. T2 - Tenth Joint BER II and BESSY II User Meeting CY - Berlin, Germany DA - 05.12.2018 KW - Aluminium alloys KW - Creep KW - Damage KW - Synchrotron X-ray refraction KW - Electron microscopy KW - Subgrain structure PY - 2018 AN - OPUS4-46861 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn T1 - Glass-ceramic composite multilayer structures - modeling of densification and shrinkage mismatch N2 - Low temperature co-fired ceramics (LTCC) are glass-ceramic composites that are processed by tape casting and multilayer technology to create multilayer circuit boards and electronic packages for high frequency applications, microsystems, and sensors. Pressure-assisted sintering (PAS) enables the densification of LTCC without lateral shrinkage, and thereby the manufacturing of miniaturized modules with minimal shrinkage tolerances. Co-firing of LTCC with other functional ceramics facilitates the implementation of innovative module concepts. The master sintering curve model is a useful tool to supplement the empirical optimization of such sintering processes. Two applications of the model are presented. Firstly, an algorithm is deduced that allows the simulation of shrinkage mismatch in a combined multilayer structure. Based on this simulation, an optimized process for the co-firing of LTCC and ferrite is derived. Secondly, the pressure-assisted sintering of LTCC is modeled. A comprehensive description of the densification behavior of LTCC during PAS is thereby possible. T2 - 14. Treffen des DGG-DKG Arbeitskreises "Glasig-kristalline Multifunktionswerkstoffe" CY - Berlin, Germany DA - 25.02.2016 KW - low temperature co-fired ceramics KW - master sintering curve KW - pressure-assisted sintering KW - multilayer PY - 2016 AN - OPUS4-35419 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn T1 - Tailoring the surface properties of glass-ceramic-composite substrates by advanced pressure-assisted sintering T2 - Junior Euromat 2012 CY - Lausanne, Switzerland DA - 2012-07-23 PY - 2012 N1 - Geburtsname von Mieller, Björn: Brandt, B. - Birth name of Mieller, Björn: Brandt, B. AN - OPUS4-26398 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Widjaja, Martinus Putra T1 - General update of the PhD work for mid_term consortium meeting N2 - Before the multiscale model is used to calculate real scale composite structures, a study to improve the effectiveness is required, especially the computation time. The reduced volume method has been studied and proved to be useful for the multiscale model of Mines ParisTech. T2 - Mid_Term Consortium Meeting of FiBreMoD CY - Imperial College London, United Kingdom DA - 11.09.2018 KW - Reduced volume method KW - Integral range KW - Composite pressure vessels KW - Multiscale model KW - Fibre breaks PY - 2018 AN - OPUS4-48570 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Bernd R. T1 - Microstructure characterization of materials using X-ray refraction techniques N2 - X-ray refraction is an excellent tool for the characterization of the microstructure of materials. However, there are only a few (synchrotron) laboratories in the world that use this technique for material characterisation. Therefore, the seminar will first explain the basic principles of X-ray refraction and the measurement techniques installed at the hard X-ray beamline BAMline at BESSY II (Berlin, Germany). This is followed by examples of investigations on fibre-reinforced plastic composites (CFRP) as well as ceramic (Cordierite, ZrO2-SiO2) and metallic materials (Ti-6Al-4V, Inconel). Some of the investigations were carried out both ex-situ and in-situ under mechanical and thermal load. The results are correlated with the mechanical properties of the materials. T2 - LNLS Users Group Seminar Series CY - Campinas, Brasil DA - 25.10.2022 KW - X-ray refraction KW - Analyzer-Based Imaging KW - BAMline PY - 2022 AN - OPUS4-56117 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evans, Alexander T1 - Residual stresses in am review and oulook of activities at BAM N2 - Critical discussion of residual stress Analysis in additive manufacturing from examples in literature and an overview of activities at BAM T2 - Workshop on Fatigue of Additive Manufactured Metallic Components CY - BAM, Berlin, Germany DA - 16.05.2019 KW - Diffraction KW - Additive Manufacturing KW - Residual stress PY - 2019 AN - OPUS4-49843 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Evsevleev, Sergei T1 - Stress partitioning and damage evolution in near-eutectic cast AlSi12CuMgNi alloy N2 - Near eutectic cast Al–Si alloys are the basis of all Al-alloys used for pistons due to their high fluidity and relatively high strength-to-weight ratio. Their microstructure is characterized by the presence of eutectic-Si embedded in an age hardenable -Al matrix. During solution heat treatment, the eutectic Si network undergoes a process of gradual disintegration, reducing the load bearing capability and the strength of the alloy. The improvement of the high temperature strength is achieved by addition of transition elements such as Cu, Mg or Ni through the formation of stiff intermetallic (IM) phases. In present study a near-eutectic AlSi12CuMgNi alloy produced by squeeze casting was investigated in as-cast condition. The in-situ neutron diffraction compression tests revealed the stress partitioning mechanism between phases of the alloy. Large stresses were found in IMs, showing their significant role as a reinforcement elements. After the failure of IM and Si phases the load is transferred back to the Al matrix, inducing further plastic deformation in it, yet without creating microcracking. The neutron diffraction experiments were coupled with assessment of internal damage after ex-situ compression tests by synchrotron radiation computed tomography. The quantitative analysis of CT data revealed that local tensile stresses in IM and Si phases induce microcracks with preferential orientation, parallel to the axis of applied load. Altogether, present experimental data was used as an input for the developed micromechanical model based on Maxwell homogenization scheme. In contrast to the neutron diffraction experiment, which can only determine stress differences between the axial and radial sample directions, the model allows predicting the principal stresses in each phase of the alloy. T2 - European Conference on Residual Stresses - ECRS10 CY - Leuven, Belgium DA - 11.09.2018 KW - Aluminum alloy KW - Intermetallics KW - Computed tomography KW - Neutron diffraction KW - Stress analysis KW - Load partition PY - 2018 AN - OPUS4-46054 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Sophie T1 - Material development for oxide multilayer generators N2 - Thermoelectric generators can be used for energy harvesting by directly transforming a temperature gradient into a voltage. Multilayer generators based on low-temperature co-fired ceramics technology (LTCC) are an interesting alternative to conventional π-type generators. They exhibit several advantages like high filling factor, possibility of texturing, co-firing of all materials in one single-step, and reduction of production costs due to the high possible degree of automation. Pressure-assisted sintering enables the theoretical possibility of co-firing two promising oxide thermoelectric materials: Ca3Co4O9 (p-type) and CaMnO3 (n-type). Due to the large difference in sintering temperature (300 K) the process is very challenging. In this work we show the material development of Ca3Co4O9, CaMnO3, insulation and metallization for multilayer generators co-fired under pressure at 900 °C. The materials are tailored regarding their sintering behavior, electrical performance and coefficients of thermal expansion. Different generator designs (unileg and pn-type) were fabricated and analyzed regarding crack formation, interaction layers and thermoelectric performance. Simulated stresses during cooling in the multilayers are compared with actual crack formation for different sintering conditions. This study shows that a lower pressure level and a lower level of complexity are beneficial for co-firing and performance. T2 - 45th International Conference and Expo on Advanced Ceramics and Composites (ICACC 2021 Virtual) CY - Online meeting DA - 08.02.2021 KW - Thermoelectrics KW - Multilayer PY - 2021 AN - OPUS4-52462 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Powierza, Bartosz T1 - In-situ CT observation of water migration in heated concrete N2 - In order to study damage in concrete exposed to fire, a series of continuous X-ray computed tomography (CT) measurements were performed on a concrete sample heated, in-situ, on one side. The water migration relative to time and 3D space and, in particular, the dynamic condensation and vaporization of water droplets in the pores was quantified. This approach shows significant potential for further investigation of fire-related concrete damage. T2 - 3rd International Conference on Tomography of Materials and Structures CY - Lund, Sweden DA - 26.06.2017 KW - In-situ KW - X-ray CT KW - Heated concrete KW - Pores KW - Water migration KW - Fire PY - 2017 UR - http://meetingorganizer.copernicus.org/ICTMS2017/ICTMS2017-29.pdf AN - OPUS4-43062 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hassenstein, Christian T1 - Automated self-adjustment of array probe with a robotic ultrasonic test system N2 - Ultrasonic testing (UT) of objects with complex geometries often requires the use of a robotic arm to position the probe perpendicular to the local surface. Using immersion makes it possible to test these objects with standard ultrasonic linear array probes. Here, the probe positions and orientations provided by the robot are used for merging the locally acquired image data into a 3D-reconstruction. The quality of this reconstruction is highly dependent on the alignment of the tool center point (TCP) of the physical probe with the TCP used in the digital model. For common industrial tools, the TCP is usually acquired using geometric features of the tools. However, for ultrasonic arrays in immersion, there is a water standoff between the probe and the test object, therefore the TCP is in free space in front of the array and cannot be acquired with the common method. To overcome this challenge, we propose a method that allows the robotic ultrasonic system to automatically self-adjust the positioning of the UT probe using a test block made of steel with defined geometric features as a target for referencing. For each of the six degrees of freedom, a scan and adjustment routine are established using the data acquired by the UT probe to update the TCP’s position and orientation in the robot control. Given a coarse pre-definition of the TCP and the known target test block, no human interaction is required while the system determines the optimum tool position and orientation. Part of this work will be used to improve and extend standards for robotic ultrasonic test systems, e.g. ISO 24647. T2 - 20th World Conference On Non-Destructive Testing CY - Incheon, South Korea DA - 27.05.2024 KW - Ultrasonic KW - Testing KW - Automation KW - Robotics KW - NDT 4.0 PY - 2024 AN - OPUS4-60565 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan T1 - Influence of the pressure difference on the safety characteristics of dusts and potential ignition sources for hybrid mixtures N2 - In the standards for the determination of safety characteristics of dusts an initial pressure difference of 400 mbar (all: abs) is applied, that increases to 1013 mbar to achieve a homogeneous dust-air mixture. Since the measuring equipment accuracy is given with ± 0,1 bar the initial pressure could range somewhere between 300 and 500 mbar and the pressure increase between 500 and 700 mbar, leading to a testing pressure of 800 to 1200 mbar. This variation does not only affect the testing pressure but also the concentration of dust and the level of turbulence, leading to wrong values of Pmax, Kst and assigning them to wrong concentrations. When tests for hybrid mixtures are conducted there are more degrees of freedom leading to even higher variations. To overcome these variations a higher accuracy is demanded for hybrid mixture testing. Further, in this presentation four standardized ignition sources are presented. T2 - Global Dust Safety Conference CY - Halifax, Canada DA - 01.03.2021 KW - hybrid mixtures, ignition sources, safety characteristics PY - 2021 AN - OPUS4-53557 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hassenstein, Christian T1 - Automatisierte Wanddickenbestimmung an Prüfteilen mit komplexen Geometrien aus anisotropen Werkstoffen N2 - Im Rahmen des Projektes MRO2.0, das sich mit der digitalen Transformation des Servicezyklus von modernen Gasturbinenschaufeln beschäftigt, wurde gezeigt, wie sich automatisiert und flächendeckend die (Rest-)Wanddicke an variabel gekrümmten Prüfgeometrien bestimmen lässt. Es wurde ein Roboterarm verwendet, der ein lineares Ultraschallarray in Tauchtechnik führt und Prüfdaten aufnimmt, die mit einer adaptierten TFM (Total Focusing Method) zu Rekonstruktionen der Außen- und Innenoberfläche verarbeitet werden. In der aktuellen zweiten Projektphase wird die Methode für Werkstoffe erweitert, die anisotrope akustische Eigenschaften aufweisen. In diesem Beitrag wird eine Methode vorgestellt, wie sich die Kristallausrichtung bzw. die richtungsabhängige Schallgeschwindigkeit mittels eines linearen Ultraschallarrays bestimmen lässt. Für den Sendefall eines Randelements in Kontakttechnik können dabei Wellen identifiziert werden, die sich parallel zur Prüfkopfapertur im Prüfobjekt ausbreiten und mit der richtungsabhängigen Schallgeschwindigkeit skalieren. Die ermittelte Schallgeschwindigkeitsverteilung kann dann verwendet werden, um die lokale Wanddickenbestimmung für die Anisotropie zu adaptieren. T2 - 6. Workshop Messtechnische Anwendungen von Ultraschall CY - Drübeck, Germany DA - 17.06.2024 KW - Ultraschallprüfung KW - Anisotropie KW - Turbinenschaufel KW - NDT 4.0 PY - 2024 AN - OPUS4-60568 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan T1 - Comparative study on standardized ignition sources used for explosion testing N2 - For the determination of safety characteristics of gases, vapors and dusts different types of ignition sources are used in international standards and guidelines. Table 1 compares technical relevant ignition sources with their main features. The paper presents test results of a comparative calorimetric and visual study between four different types of ignition sources. The ignition procedures were analyzed visually with a high-speed camera and electric recordings. In addition to that, the influence of the electrode-orientation, -distance as well as ignition energy on the reproducibility of the exploding wire igniter was tested. The exploding wire is already in use for standardized determination of safety characteristics of gases, first tests on the suitability of the exploding wire igniter for dust testing have been carried out by Scheid et al. Using the exploding wire, the ignition energy can be varied from 2 to 10 000 J (2 x 5 000 J) and thus it could be used for gases, vapors, dusts and hybrid mixtures. Moreover it can be used at high initial pressures and it is the only ignition source with an easily measurable ignition energy release. Furthermore, it does not introduce another chemical reaction into the system. Finally, a proposal for a standard ignition source for explosion tests on hybrid mixtures is derived from the test results. T2 - 13th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions CY - Braunschweig, Germany DA - 27.07.2020 KW - Ignition source KW - Exploding Wire KW - Safety characteristics determination KW - Hybrid mixtures PY - 2020 AN - OPUS4-51691 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Florian, Camilo T1 - Optical thickness-profiling for fs-laserinduced superficial amorphization and oxide removal on silicon N2 - Amorphization and re-crystallization of polished silicon wafers cut in <111> and <100> orientation were studied after irradiation by single Ti:sapphire femtosecond laser pulses (790 nm, 30 fs) using optical imaging, topographic characterization, and transmission electron microscopy. Spectroscopic imaging ellipsometry (SIE) enabled fast data acquisition at multiple wavelengths and provided experimental data for calculating the amorphous layer thickness profiles with lateral resolution in the micrometer and vertical resolution in the nanometer range based on a thin-film layer model including the topmost native oxide. For a radially Gaussian shaped laser beam and at moderate peak laser fluences above the melting but below the ablation threshold, laterally parabolic amorphous layer profiles with maximum thicknesses of some tens of nanometers were quantitatively derived. Moreover, the threshold fluence of the native oxide removal was quantified. At laser peak fluences closely below the ablation threshold of silicon, SIE is capable to reveal even the laser-induced removal and formation of the native oxide covering the Si wafers under ambient air conditions. The accuracy of these all-optical, non-destructive SIE-based layer thickness assessments is verified experimentally through high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (STEM-EDX). Along with topographic information obtained by atomic force microscopy (AFM), a comprehensive picture of the oxide removal and superficial re-solidification of silicon after local melting by femtosecond laser pulses can be drawn. T2 - E-MRS Spring Meeting 2025 CY - Strasbourg, France DA - 26.05.2025 KW - Femtosecond laser KW - Laser-induced amorphization KW - Native oxide layer KW - Spectroscopic imaging ellipsometry KW - Transmission electron microscopy PY - 2025 AN - OPUS4-63275 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Bacterial adhesion on ultrashort pulse laser processed surfaces ― more than size matters! N2 - Bacterial biofilms are aggregates of bacterial cells, often attached to a surface and enclosed by a self-produced extracellular matrix which confers increased stress tolerance and resistance to cleaning. Biofilm formation leads to biofouling which gives rise to high costs in numerous technical settings due to biocorrosion and biodegradation. However, biofilms can also be attractive for industrial settings such as wastewater treatment systems or for soil bioremediation processes. Hence, the control of bacterial adhesion to a surface is of major concern. Surface topography strongly influences bacterial adhesion. Therefore, one promising way to achieve bacteria-guiding surfaces lies in the contactless and aseptic large-area laser processing of technical surfaces. We used short and ultrashort pulsed laser systems to generate different surface textures, mainly high-spatial-frequency and low-spatial-frequency laser-induced periodic surface structures, LIPSS (HFSL and LFSL), on Ti, Ti-alloy, steel, and polymers (PET and PE). Pristine (polished) and laser processed samples were subjected to bacterial adhesion experiments with two different Escherichia coli strains and Staphylococcus aureus as test organisms. The bacterial strains differed in their cell wall structure (grampositive vs. gramnegative strains), in size, shape, the occurrence of cell appendages, and in their biofilm forming capabilities. Adhesion patterns were analyzed microscopically and compared regarding the respective test strain and surface topography. Our results revealed that adhesion behavior strongly depends not only on the material’s topography and chemistry, but also on the specific bacterial strain, the presence of cell appendages, and ambient growth conditions. T2 - 13th International Conference on Photoexcited Processes and Applications, ICPEPA-13 CY - Lecce, Italy DA - 14.09.2025 KW - Biofilm KW - Bacterial adhesion KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses PY - 2025 AN - OPUS4-64166 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kaczmarek, D. A1 - Bonse, Jörn T1 - Capabilities and limitations of Sipe’s first principles LIPSS theory: current aspects and directions N2 - This presentation elucidates the fundamentals and capabilities of John E. Sipe’s first principles theory (1983) of laser-induced periodic surface structures (LIPSS), representing an analytical mathematical approach (Green’s formalism) to calculate the absorption of electromagnetic radiation at a microscopically rough surface via the so-called efficacy factor. It includes a discussion of assumptions made in the theory and resulting limitations, such as the restriction to a near-surface layer (the so-called “selvedge”), the lack of any material response, or missing inter-pulse feedback phenomena being relevant in typical multi-pulse irradiation conditions. The influence of the angle of incidence, the polarization direction (s-pol. or p-pol.), the optical properties (dielectric permittivity) of the irradiated materials, as well as its surface roughness and its specific encoding in the theory via a shape factor (s) and a filling factor (f) are addressed. A simplifying mathematical reformulation (without changing the validity range) of Sipe’s theory in the form of 14 complex-valued equations published in 2005 is motivated, as well as the necessity of some minor adjustments for non-normal incident radiation - revealed in a very recent Erratum. Starting with 2009, extensions of the original theory were developed, e.g., the analytical Sipe-Drude model in order to include intra-pulse transient changes of the optical properties of the material. Finite-difference time-domain (FDTD) numerical simulations successfully confirmed in 2012 the validity of the Sipe-Drude approach. Moreover, the FDTD formalism can be extended to sub-surface regions and can be combined with a material response (topography) modelling for iteratively considering inter-pulse feedback phenomena. Finally, we will provide characteristic examples of Sipe’s efficacy factor for typical material classes (metals, semiconductors, dielectrics), we will explain how the results can be interpreted, and line out how the Sipe theory may be extended further. T2 - 12th International LIPSS Workshop CY - Leipzig, Germany DA - 11.09.2024 KW - Laser-induced periodic surface structures (LIPSS) KW - Theory KW - Green's formalism KW - Scattering waves KW - Finite-difference time-domain calculations PY - 2024 AN - OPUS4-61098 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Laser Nanotexturierung von Metalloberflächen zur Reduktion von Reibung und Verschleiß N2 - Die Reduktion von Reibung und Verschleiß in technischen Systemen bietet ein großes Potenzial zur Reduktion von CO2-Emissionen. Dieser Beitrag diskutiert die Erzeugung und tribologische Charakterisierung von Ultrakurzpuls-generierten Nanostrukturen auf Metallen (Stahl, Titan). Besonderes Augenmerk wird dabei auf die Rolle der laserinduzierten Oxidschicht im Zusammenspiel mit verschleißreduzierenden Additiven in ölbasierten Schmiermitteln gerichtet. T2 - Online Abendvortrag beim AWT Härterei- und Werkstoffkreis Bodensee der Arbeitsgemeinschaft Wärmebehandlung + Werkstofftechnik e.V. CY - Online meeting DA - 16.01.2025 KW - Additive KW - Laser-induzierte periodische Nanostrukturen KW - Reibungsreduktion KW - Verschleißreduktion PY - 2025 AN - OPUS4-62432 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Voss, Heike T1 - Morphology and regularity of high-spatial frequency laser-induced periodic surface structures (HSFL) on titanium materials N2 - Titanium and its alloys are known to allow the straightforward laser‐based manufacturing of ordered surface nanostructures, so‐called high spatial frequency laser‐induced periodic surface structures (HSFL). These structures exhibit sub‐100 nm spatial periods – far below the optical diffraction limit. The resulting surface functionalities are usually enabled by both, topographic and chemical alterations of the nanostructured surfaces. For exploring these effects, HSFL were processed on different titanium materials (bulk, film) upon irradiation with near‐infrared ps‐laser pulses (1030 nm wavelength, ≈ 1 ps pulse duration) under different laser scan processing conditions. Here we extend our previous work on chemical analyses of HSFL on titanium materials towards a more detailed morphological and topographical surface characterization. For that, scanning electron and atomic force microscopic images are subjected to a regularity analysis using our self-developed ReguΛarity software. The regularity of the HSFL is assessed with respect to the influences of sample- and laser-related parameters, as well as the imaging method used. T2 - 13th International LIPSS Workshop CY - Enschede, Netherlands DA - 29.10.2025 KW - Laser-induced periodic surface structures (LIPSS) KW - Titanium KW - Ultrashort laser pulses KW - Laser processing PY - 2025 AN - OPUS4-64631 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krüger, Jörg T1 - X-ray emission during ultrashort pulse laser material processing N2 - The unwanted emission of X-rays during ultrashort pulse laser material processing in air was already reported more than 20 years ago for pulse repetition rates in the 1 kHz range [1]. It was stated that an enclosure of the experimental setup is necessary to protect the operator from X-rays. By now, the use of ultrashort pulse laser technology has become established in industry using repetition rates in the multi 100 kHz up to the GHz range and laser average powers up to the kW level. Since 2018/2019, more and more investigations have been carried out on the hazards from X-rays at higher laser pulse repetition rates [2-4]. Recently, maximum X-ray skin dose rates of the order of 1 Sv/h (iron target [5]) and X-ray photon energies of up to 40 keV (tungsten target [6]) were reported. Measures must be taken to shield the unwanted X-rays. T2 - 10th Conference on Applications of Femtosecond Lasers in Materials Science (FemtoMat) CY - Mauterndorf, Austria DA - 24.02.2025 KW - Ultrashort pulse laser KW - Material processing KW - X-ray emission KW - Radiation protection PY - 2025 AN - OPUS4-62665 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Laser Nanotexturierung von Metalloberflächen zur Reduktion von Reibung und Verschleiß N2 - Die Reduktion von Reibung und Verschleiß in technischen Systemen bietet ein großes Potenzial zur Reduktion von CO2-Emissionen. Dieser Beitrag diskutiert die Erzeugung und tribologische Charakterisierung von Ultrakurzpuls-generierten Nanostrukturen auf Metallen (Stahl, Titan). Besonderes Augenmerk wird dabei auf die Rolle der laserinduzierten Oxidschicht im Zusammenspiel mit verschleißreduzierenden Additiven in ölbasierten Schmiermitteln gerichtet. T2 - Internationale Bodensee Fachtagung „Wärmebehandlung und Oberflächentechnik zur Verbesserung von Tribologie und Verschleissbeständigkeit" CY - Feldkirch, Austria DA - 20.03.2025 KW - Additive KW - Laser-induzierte periodische Nanostrukturen KW - Reibungsreduktion KW - Verschleißreduktion PY - 2025 AN - OPUS4-62757 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Generation and characterization of anisotropic nanostructures using ultrashort pulsed lasers N2 - The lecture gives an overview of the generation and characterization of anisotropic nanostructures using ultrashort pulsed laser radiation. Special attention will be paid to the phenomenon of so-called laser-induced periodic surface structures (LIPSS) on various materials. One focus will be on dielectrics and the dynamics of nanostructure formation. Further examples of bulk nanostructures from the literature will be discussed. T2 - 8th UKP-Workshop: Ultrafast Laser Technology CY - Aachen, Germany DA - 08.04.2025 KW - Laser-induced Periodic Surface Structures (LIPSS) KW - Dielectrics KW - Surface Nanostructures KW - Volume Nanostructures PY - 2025 AN - OPUS4-62947 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan T1 - Entwicklungen zu Bestimmungsverfahren für sicherheitstechnische Kenngrößen des Explosionsschutzes für hybride Gemische N2 - Zur Bestimmung sicherheitstechnischer Kenngrößen (STK) von hybriden Gemischen (Gemisch aus mindestens zwei brennbaren Phasen, wie z.B. Staub/Gas- oder Gas/Dampf-Gemisch) existieren bislang keine einheitlichen, genormten Prüfmethoden. Die Normen und Regelwerke zur Bestimmung der STK von einphasigen brennbaren Systemen (Staub, Gas, Dampf) unterscheiden sich teilweise erheblich. Beispielsweise sind in den jeweiligen Normen für Stäube, Gase und Dämpfe unterschiedliche Zündquellen und Zündenergien definiert. Des Weiteren unterscheiden sich die in den Normen definierten Prüfabläufe bei der Gemischherstellung. Bei der Entwicklung einer einheitlichen Norm für hybride Gemische muss der Einfluss dieser beiden Parameter ermittelt werden, um die Vergleichbarkeit mit den STK der einzelnen Komponenten Gas, Staub und Dampf gewährleisten zu können und bisherige Erkenntnisse zu hybriden Gemischen interpretieren und bewerten zu können. T2 - VDI-Fachtagung "Sichere Handhabung brennbarer Stäube" CY - Online meeting DA - 04.11.2020 KW - Hybride Gemische KW - Explodierender Draht KW - Sicherheitstechnische Kenngrößen KW - Zündquellen PY - 2020 AN - OPUS4-51692 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lucaßen, J. T1 - Bottom-up grown CISe micro absorber arrays: microstructure analysis and solar cell integration N2 - A reduction of critical raw materials like indium and gallium in chalcopyrite thin-film solar cells is aimed for the micro-concentrator concept. Bottom-up grown micro absorbers for operation under light concentration on the micrometer scale allow improved heat dissipation. T2 - 41st European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC 2024) CY - Vienna, Austria DA - 23.09.2024 KW - Laser-assisted MO-CVD KW - CISe micro-absorber KW - Micro solar cell arrays KW - Solar cell efficiency PY - 2024 AN - OPUS4-62075 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Ultrafast optical probing of laser-induced formation of periodic surface nanostructures N2 - Laser-induced Periodic Surface Structures (LIPSS, ripples) are a universal phenomenon and can be generated in a contactless, single-step process on almost any type of solid upon irradiation with intense laser pulses. They represent a (quasi-)periodic modulation of the surface topography in the form of a linear grating and are typically formed in a “self-ordered” way in the focus of a coherent laser beam. Thus, they are often accompanying laser material processing applications. The structural sizes of LIPSS typically range from several micrometers down to less than 100 nanometers – far beyond the optical diffraction limit – while their orientations exhibit a clear correlation with the local polarization direction of the laser radiation. From a theoretical point of view, a controversial debate has emerged during the last decades, whether LIPSS originate from electromagnetic effects (seeded already during the laser irradiation) – or whether they emerge from matter-reorganization processes (distinctly after the laser irradiation). From a practical point of view, however, LIPSS represent a simple and robust way for the nanostructuring of solids that allows creating a wide range of different surface functionalities featuring applications in optics, tribology, medicine, energy technologies, etc. The presentation provides an overview of current theories on LIPSS and the quest to achieve ever smaller surface nanostructures. The historical development of the fundamental ideas behind LIPSS is presented, together with experimental approaches that make it possible to distinguish between the various LIPSS formation scenarios. Time-resolved experimental methods are required to investigate the dynamics of their formation. The presentation focuses on ultrafast time-resolved optical (pump-probe) techniques that can be used for localized point measurements or microscopic imaging, utilizing the reflection, diffraction, or coherent scattering of the probe radiation at the emerging LIPSS, while simultaneously capturing information about rapid melting, ablation, and solidification phenomena. However, given the sub-micrometric spatial periods of LIPSS, their analysis using optical radiation employed in far-field techniques remained a challenge. Therefore, short wavelengths of the probe beam in the UV range or even below are required to overcome the diffraction limit imposed in the optical spectral range. Fourth-generation light sources, namely short-wavelength (XUV or X-ray) short-pulse free-electron lasers (FELs), offer new and fascinating possibilities for resolving laser-induced structure formation on surfaces in the sub-micrometer to nanometer range and in time domains from picoseconds to several nanoseconds with a resolution in the sub-picosecond regime. On laser-irradiated semiconductor surfaces, this unique spatio-temporal resolution enables the detection of early signs of coherent/plasmonic electromagnetic scattering effects, followed by the excitation of hydrodynamic capillary waves – providing new insights into the above-mentioned debate. Recent experiments at the European XFEL used fs-time-resolved small-angle X-ray scattering (fs-SAXS) and even fs-time-resolved grazing incidence small-angle X-ray scattering (fs-GISAXS), combined with grazing-incidence diffraction (fs-GID), to reveal the dynamics of the formation of nanometric LIPSS on metals. T2 - CINSaT Herbstkolloquium 2025 CY - Kassel, Germany DA - 05.11.2025 KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses KW - Pump-probe measurements KW - Free-electron laser KW - Small angle X-ray scattering (SAXS) PY - 2025 AN - OPUS4-64633 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hassenstein, Christian T1 - Robotergestützte Ultraschallprüfung von Objekten mit komplexen Geometrien N2 - Durch den Einsatz moderner digitaler Design- und Fertigungsmethoden wachsen einerseits die Komplexität von Bauteilen, andererseits der Bedarf an Informationen über deren Qualität und Zustand. Damit steigen auch die Anforderungen an die zerstörungsfreie Prüfung, die im Zuge von ZfP 4.0 automatisierte und flexible, innovative Prüfmethoden erfordert. Das gilt insbesondere für Objekte, deren Oberflächengeometrien über plane Flächen und eindimensionale Krümmungen hinausgehen. Um zu zeigen, wie eine Ultraschallprüfung von Objekten mit komplexer Oberflächengeometrie realisiert werden kann, wurde an der BAM eine roboterbasierte Demonstratoranlage entwickelt. Dabei führt ein Roboterarm einen Array-Prüfkopf in Tauchtechnik senkrecht über die Prüffläche. Die dafür erforderliche Prüfbahn kann entweder anhand der CAD-Geometrie oder mithilfe einer Punktewolke der Prüffläche, die vorab mit einem am Roboter angebrachten Laser-Profilometer erfasst wird, ermittelt werden. Zur Erhöhung der Genauigkeit werden der Lasersensor und der Ultraschallprüfkopf automatisiert mit dafür entwickelten Routinen am Roboter eingemessen. Durch bildgebende Verfahren und eine automatische Auswertung der Bilder kann die in Tauchtechnik auftretende Brechung des Schallbündels an der Prüfteiloberfläche berücksichtigt werden, was die ortsrichtige Rekonstruktion von Anzeigen aus dem Prüfteilinneren bzw. der Rückwand ermöglicht. Durch Rückführung der Anzeigen in ein gemeinsames Koordinatensystem entsteht eine 3D-Rekonstruktion des Prüfteils. Der vorliegende Beitrag stellt die Demonstratoranlage und die angewendeten Methoden im Detail vor und nennt Anwendungsbeispiele. T2 - DGZfP Jahrestagung 2025 CY - Berlin, Germany DA - 26.05.2025 KW - Ultraschall KW - Robotik KW - Turbinenschaufel KW - Wanddicke KW - Defekterkennung PY - 2025 AN - OPUS4-63417 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Voss, Heike T1 - ReguΛarity - A free software for the objective quantification of the regularity of periodic surface structures generated by femtosecond laser irradiation N2 - The precise laser-based surface structuring on the micro- and nanoscale allows to create functional properties for innovative applications, e.g., in medicine, optics and biology. Among the various types of surface structures, laser-induced periodic surface structures (LIPSS) are characterized by their versatility and the relatively simple manufacturing process. However, the fabrication of highly regular LIPSS patterns remains challenging. The systematic investigation of LIPSS formation, as well as of the resulting functional properties requires a precise evaluation of the surface morphology, especially with regard to periodicity and regularity. Existing quantification methods such as Fast Fourier Transformation (FFT) tend to lack automation and objectivity, especially when dealing with large data sets and multi-scale structures. Although automated approaches exist with the Gini coefficient and the P³S method, their limited availability restricts a broader scientific use. We therefore introduce ReguΛarity as an innovative open-source software solution for objective, rapid and reproducible evaluation of structured surfaces concerning their regularity. In order to provide comprehensive surface morphological analysis, our software uses advanced image-processing techniques and integrates the already developed tools such as P³S method, Gini coefficient, FFT analysis, and the calculation of DLOA (Dispersion of LIPSS Orientation Angle). The software allows to evaluate any relevant image format as provided, e.g., by standard scanning electron micrographs. An intuitive PyQt5-based interface, enhanced by multi-threading capabilities, facilitates efficient data processing. Interactive features such as region-of-interest selection and plotting provide flexible adaptation to diverse applications. ReguΛarity offers a robust analysis tool that will contribute to the further development of precise laser-based surface structuring and to the optimization of the desired functional properties in both research and industry. T2 - 13th International Conference on Photoexcited Processes and Applications, ICPEPA-13 CY - Lecce, Italy DA - 14.09.2025 KW - Laser-induced periodic surface structures (LIPSS) KW - Laser processing KW - Fourier transformation KW - Regularity PY - 2025 AN - OPUS4-64176 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rahner, E. T1 - From nightmare to numbers - A novel software tool for objective regularity analysis of LIPSS N2 - The precise laser-based surface structuring on the micro- and nanoscale allows for the creation of functional properties for innovative applications, e.g., in medicine, optics and biology. Among the various types of surface structures, laser-induced periodic surface structures (LIPSS) are distinguished by their versatility and the comparatively simple manufacturing process. Nevertheless, the fabrication of highly regular LIPSS patterns remains challenging. The systematic investigation of LIPSS formation, as well as of the resulting functional properties demands accurate and objective evaluation of surface morphology, especially regarding periodicity and regularity. Existing quantification methods such as Fast Fourier Transformation (FFT) tend to lack automation and objectivity, especially when dealing with large data sets and multi-scale structures. Although automated approaches, such as those based on the Gini coefficient or the P³S method, have been proposed, their limited availability hinders a broader scientific use. To overcome these limitations, we introduce ReguΛarity, a novel, freely available Python-based software tool featuring a graphical user interface for automated and quantitative assessment of regularity in period and (quasi-)periodic surface patterns including LIPSS. The software processes microscopic images obtained from optical, scanning electron microscopy (SEM), or atomic force microscopy (AFM), combining image segmentation with one- and two-dimensional Fourier analyses (1D-FT, 2D-FT), phase evaluation, and gradient-based orientation determination to facilitate a comprehensive regularity analysis of (quasi-)periodic surface patterns with spatial periods Λ. Regularity is quantified by the newly proposed five-dimensional regularity tuple R comprising the normalized spread of spatial periods from 2D-FT, the normalized local variation of the dominant spatial period from 1D-FT, the Gini coefficient G, the Dispersion of the LIPSS Orientation Angle (DLOA), and the mean phase deviation. The demonstration of the software’s capabilities is achieved by comparing idealized sinusoidal test patterns with SEM micrographs of fs-laser-generated LIPSS on stainless steel (AISI 316L) and aluminum alloy (AlMg5). This comparison highlights ReguΛarity’s objective differentiation between varying levels of structural regularity. The software facilitates high-throughput analysis and data-driven optimization in laser surface engineering processes. T2 - 13th International LIPSS Workshop CY - Enschede, Netherlands DA - 29.10.2025 KW - Laser-induced periodic surface structures (LIPSS) KW - Surface functionalization KW - Fourier transform KW - Gini coefficient PY - 2025 AN - OPUS4-65047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gräf, S. T1 - Ion marker implantation as key to understand the formation of femtosecond LIPSS on steel N2 - Ultrashort laser (fs-laser) pulses can be used to generate laser-induced periodic surface structures (LIPSS, ripples) on different types of materials. A variety of potential applications of these grating-like LIPSS have already been demonstrated in the field of surface functionalization. Examples include structural colours (e.g. for optical effects or safety features), beneficial friction and wear reduction, modification of the wetting behaviour of surfaces, and antibacterial or cell adhesion promoting properties for medical implants. Despite decades of research, however, some aspects regarding the formation mechanism are still unclear and the subject of controversial debate. This involves the two main models of coherent electromagnetic scattering and matter reorganization, which are used for explaining aspects of LIPSS formation and phenomenology. One major issue is to quantify the actual amount of material removal during the fs-laser processing due to the lack of an independent depth reference and to visualize the so-called heat-affected zone accompanying intense fs-laser irradiation. In the present study, near-surface implantation of Mn and N ions into different material depth of Mn-free austenitic stainless steel alloy FeCrNiMo18-12-2 was used to create reference layers of a defined thickness containing the respective elements. LIPSS (type low-spatial frequency LIPSS, LSFL) were fabricated on the polished substrate surfaces in an air environment by fs-laser irradiation (λ = 1025 nm, τ = 300 fs, frep = 100 kHz, F = 1.5 J/cm2). The implanted layers subsequently served as a kind of coordinate system to assess the material removal during the formation process via cross-sectional Transmission Electron Microscopy (TEM) and Energy Dispersive X-ray Spectroscopy (EDXS). Using both analysis methods enabled in particular to determine the position of peaks and valleys of the LIPSS topography in relation to the initial surface before fs-laser irradiation. This confirmed the selective ablation in the LIPSS valleys. Moreover, linking changes in the material’s microstructure, e.g., the crystallinity and near surface elemental composition before and after fs-laser treatment, gave additional insights regarding the transient cooling rates, as recently shown for NiTi alloys. T2 - 13th International LIPSS Workshop CY - Enschede, Netherlands DA - 29.10.2015 KW - Energy dispersive X-ray analysis (EDX) KW - Ion implantation KW - Laser-induced periodic surface structures (LIPSS) KW - Steel KW - Transmission electron microscopy (TEM) PY - 2025 AN - OPUS4-64900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bonse, Jörn T1 - Bacterial adhesion on ultrashort pulse laser processed surfaces ― more than size matters! N2 - Bacterial biofilms are aggregates of bacterial cells, often attached to a surface, and enclosed by a self-produced extracellular matrix which confers increased stress tolerance and resistance to cleaning. Biofilm formation leads to biofouling which gives rise to high costs in numerous technical settings due to biocorrosion and biodegradation. However, biofilms can also be attractive for industrial settings such as wastewater treatment systems or for soil bioremediation processes. Hence, the control of bacterial adhesion to a surface is of major concern. Surface topography strongly influences bacterial adhesion. Therefore, one promising way to achieve bacteria-guiding surfaces lies in the contactless and aseptic large-area laser processing of technical surfaces. We used short and ultrashort pulsed laser systems to generate different surface textures, mainly high-spatial-frequency and low-spatial-frequency laser-induced periodic surface structures, LIPSS (HFSL and LFSL), on Ti, Ti-alloy, steel, and polymers (PET and PE). Pristine (polished) and laser processed samples were subjected to bacterial adhesion experiments with two different Escherichia coli strains and Staphylococcus aureus as test organisms. The bacterial strains differed in their cell wall structure (grampositive vs. gramnegative strains), in size, shape, the occurrence of cell appendages, and in their biofilm forming capabilities. Adhesion patterns were analyzed microscopically and compared regarding the respective test strain and surface topography. Our results revealed that adhesion behavior strongly depends not only on the material’s topography and chemistry, but also on the specific bacterial strain, the presence of cell appendages, and ambient growth conditions. T2 - 13th International LIPSS Workshop CY - Enschede, Netherlands DA - 29.10.2025 KW - Bacterial adhesion KW - Biofilm KW - Laser-induced periodic surface structures (LIPSS) KW - Ultrashort laser pulses PY - 2025 AN - OPUS4-64632 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Voss, Heike T1 - Morphology and regularity of high-spatial frequency laser-induced periodic surface structures (HSFL) on titanium materials N2 - Titanium and its alloys are known to enable the straightforward laser‐based manufacturing of ordered surface nanostructures, so‐called high-spatial frequency laser‐induced periodic surface structures (HSFL). These structures exhibit sub‐100 nm spatial periods – far below the optical diffraction limit. The resulting surface functionalities are usually enabled by both, topographic and chemical alterations of the nanostructured surfaces. For exploring these effects, HSFL were processed on different titanium materials (bulk, film) upon irradiation with near‐infrared ps‐laser pulses (1030 nm wavelength, ≈1 ps pulse duration) under different laser scan processing conditions in normal air atmosphere. Here, we extend our previous work on chemical analyses of HSFL on titanium materials towards a more detailed large-area morphological and topographical surface characterization. For this purpose, scanning electron or atomic force microscopic images are subjected to a regularity analysis using our ReguΛarity software. The results are assessed with respect to the influences of sample- or laser-related parameters on the regularity of the HSFL. T2 - 13th International Conference on Photoexcited Processes and Applications, ICPEPA-13 CY - Lecce, Italy DA - 14.09.2025 KW - Laser-induced periodic surface structures (LIPSS) KW - Laser processing KW - Ulltrashort laser pulses KW - Titanium PY - 2025 AN - OPUS4-64173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gräf, S. T1 - Ion marker implantation for tracing the formation of femtosecond LIPSS on steel N2 - An ion marker experiment is conducted to investigate the formation of low spatial frequency laser-induced periodic surface structures (LIPSS) on stainless steel surfaces upon scan-processing with femtosecond laser pulses (300 fs, 1025 nm, 100 kHz) focussed to a spot diameter of ~20 µm. Defined concentration depth profiles of 14N^+- and 55Mn^+-ions were implanted below the polished surface of a cast Mn- and Si-free stainless steel AISI 316L using an acceleration energy of 380 keV. This generated two distinct “depth-tracer-layers” ~135 nm (55Mn) and ~340 nm (14N) below the sample surface. The sample morphology and microstructure were evaluated before and after LIPSS-processing using scanning and transmission electron microscopy techniques in top-view and cross-sectional geometry. Energy-dispersive X-ray spectroscopy (EDXS) allowed to visualize the depth distribution of the marker elements, the steel constituents, and of oxygen involved through the laser processing in ambient air. These experiments revealed that the LIPSS on this metal are predominantly formed by material removal through locally varying ablation and, to a lesser extent, by local melt displacement effects prior to the re-solidification. Moreover, the processing in air leads to the formation of a less than 10 nm thick laser-induced oxide layer covering the steel surface. Our new tracer ion approach contributes to the ongoing debate on the relevance of electromagnetic or hydrodynamic effects during the formation of LIPSS. T2 - E-MRS Spring Meeting 2025 CY - Strasbourg, France DA - 26.05.2026 KW - Laser-induced periodic surface structures (LIPSS) KW - Steel KW - Ion implantation KW - Transmission electron microscopy (TEM) KW - Energy dispersive X-ray analysis (EDX) PY - 2025 AN - OPUS4-63274 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Grunewald, Thomas T1 - Nichtelektrischer Explosionsschutz: Zündgefahren durch Funken - Grundlagen und Maßnahmen zum Explosionsschutz N2 - Geräte und Maschinen, die zur bestimmungsgemäßen Verwendung in explosionsgefährdeten Bereichen gemäß 2014/34/EU konstruktiv vorgesehen sind, muss in der europäischen Union eine Zündgefahrenbewertung durchgeführt werden. Dabei müssen alle 13 Zündquellen betrachtet werden. Eine Teilmenge der 13 Zündquellen sind die Gefahren von nichtelektrischen Zündquellen, zu denen auch die mechanischen Schlag-, Schleif- und Reibvorgänge gehören. Bei mechanischen Schlagvorgängen kommt es infolge des Zusammenstoßes zweier Werkstücke bzw. Bauteile zu einer Umwandlung der kinetischen Energie. Dabei erhöht sich die Temperatur der Werkstoffe an der Kontaktstelle und es kommt unter Umständen zu einem Abtrennvorgang kleiner Partikel erhöhter Temperatur. Sowohl die heißen Kontaktstellen (Zündquelle "heiße Oberflächen") als auch die abgetrennten Partikel (Zündquelle "mechanisch erzeugte Funken") können eine wirksame Zündquelle für ein explosionsfähiges Gasgemisch darstellen. Zur Festlegung von Grenzwerten wurden in der Norm DIN EN ISO 80079-36:2016 die Gasgemische anhand ihrer Explosionsgruppe klassifiziert und zu jeder Gruppe die maximale Energie des Schlagvorgangs festgelegt, unter derer die Entstehung einer wirksamen Zündquelle als unwahrscheinlich angenommen werden kann. Weitere Festlegungen von Grenzwerten für die kinetische Schlagenergie und geeignete Werkstoffpaarungen finden sich u.a. in der DIN EN 1755 (ex-geschützte Flurförderzeuge) und in der DIN EN 14986 (ex-geschützte Ventilatoren). T2 - Ausbildung zum Explosionsschutzbeauftragten CY - Essen, Germany DA - 20.01.2026 KW - Schlagfunken KW - Schleiffunken KW - Reibfunken KW - Explosionsschutz KW - Nichtelektrischer Explosionsschutz KW - Mechanischer Explosionsschutz PY - 2026 AN - OPUS4-65398 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ebell, Gino T1 - Spannstahlgefährdung - Stand der aktuellen Erkenntnisse aus Sondierungen und Materialuntersuchungen N2 - Spannstahlbrücken die in der Vergangenheit mir vergüteten Spannstählen errichtet worden sind können unter ungünstigen Gegebenheiten bei deren Erstellung signifikante Probleme hinsichtlich der Tragfähigkeit bekommen. Im Speziellen kann die wasserstoffinduzierte Spannungsrisskorrosion hier bei der Errichtung der Brückenbauwerke Anrisse an den Spanndrähten erzeugt haben die Jahre später zum Versagen der Brücke führen können. Die Präsentation im Speziellen behandelt den Teileinsturz der Carolabrücke in Dresden und neue Erkenntnisse zu vergüteten Spannstählen. T2 - BMV - Workshop CY - Bonn, Germany DA - 20.01.2026 KW - Korrosion KW - Spannstahl KW - Spannungsrisskorrosion KW - Wasserstoff PY - 2026 AN - OPUS4-65403 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Koch, Claudia T1 - Ensuring Quality Smarter with a digital Quality Infrastructure (Mexican-German Technical Exchange) N2 - The presentation introduces the initiative QI‑Digital, which aims to holistically transform quality infrastructure across all its elements. To this end, a digital QI ecosystem is being developed that integrates digital QI tools with advanced methods for testing, inspection, and monitoring, and embeds them into the broader digital industrial ecosystem. Sovereign and secure data sharing and management are enabled through technologies such as data spaces, the Asset Administration Shell, verifiable credentials, and the Digital Product Passport (DPP). Particular emphasis is placed on the role of artificial intelligence in quality assurance: Several use cases and ongoing projects from BAM are presented togetehr with the business benefits they enable. Ongoing activities on the use of AI for manageing quality-related documentation are also presentated that aim at establishing an agentic AI framework for QI. The talk concludes with key lessons learned so far within the initiative. T2 - Mexican-German Technical Exchange on QI Digital CY - Mexico City, Mexico DA - 23.01.2026 KW - Quality infrastructure KW - Agentic AI KW - Digital Ecosystem PY - 2025 AN - OPUS4-65411 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn A1 - Fellinger, Tim-Patrick T1 - Berlin Battery Lab - Vom Material zur Zelle - Batterieinnovation aus Berlin N2 - Das Berlin Battery Lab (BBL) vereint exzellente Materialforschung, modernste Analytik und gezielten Technologietransfer. Als gemeinsames Labor von BAM, HZB und der Humboldt Universität zu Berlin entwickeln wir zukunftsfähige Natrium-Ionen- und Metall-Schwefel-Batterien – von der Materialidee bis zur funktionsfähigen Zelle. T2 - Batteriaforum Deutschland CY - Berlin, Germany DA - 20.01.2026 KW - Batterie KW - Kooperation KW - Natrium-Ionen KW - BBL PY - 2026 AN - OPUS4-65410 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ruehle, Bastian T1 - MINERVA-OS: The Orchestrator of our SDL for Nano and Advanced Materials Synthesis N2 - We present our SDL "Minerva" and its' Orchestrator "Minerva-OS". We discuss the general architecture of the orchestrator, the problems our orchestration solution solves, associated objectives, and success criteria. We demonstrate how a user would interact with it and give examples of what it has already been used for. We also provide some explanation of the available and planned features, and how workflows/experiments are represented. Lastly, we discuss key technical challenges we faced during development. T2 - Orchestration Alignment Virtual Workshop CY - Online meeting DA - 20.01.2026 KW - Self Driving Labs KW - Materials Acceleration Platforms KW - Workflows KW - Orchestration PY - 2026 AN - OPUS4-65422 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Absorption and Refraction Techniques: Characterization and Non-Destructive Testing of Additively Manufactured Materials N2 - The combination of tomographic, microstructural data with other experimental techniques and with modeling is paramount, if we want to extract the maximum amount of information on material and component properties. In particular, quantitative image analysis, statistical approaches, direct discretization of tomographic reconstructions represent concrete possibilities to extend the power of the tomographic 3D representation to insights into the material and component performance. This logic thread equally holds for industrial and academic research, and valorizes expensive experiments such as those carried out at synchrotron sources, which cannot be daily repeated. I will show a few examples of possible use of X-ray tomographic data for quantitative assessment of damage evolution and microstructural properties, as well as for non-destructive testing. Examples of micro-structured inhomogeneous materials will be given, such as Composites, Ceramics, Concrete, and Additively manufactured parts. I will also show how X-ray refraction computed tomography (CT) can be highly complementary to classic absorption CT, being sensitive to internal interfaces. Additionally, I will present a new technique in our portfolio, Neutron Diffraction, which is extremely well suited to the study of internal stresses, both residual and under external load. T2 - Kolloquium an dem ‘Laboratoire National de Metrologie et d’Essais CY - LNE’ Paris, France DA - 09.06.2016 KW - Computertomographie KW - Metrologie KW - 3D Mikrostruktur KW - Zerstörungsfreie Prüfung KW - Röntgenrefraktion KW - Additive Fertigung KW - TF Material KW - Analytical Science PY - 2016 AN - OPUS4-38826 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maiwald, Michael T1 - Erfahrungsaustausch Labor-Robotik N2 - Die BAM setzt in ihren analytischen Labors zunehmend Labor-Robotik ein, um gefähliche oder zeitraubende Routineaufgaben zu automatisieren. Durch Automation kann auch die Reproduzierbarkeit solcher Anwendungen erhöht werden. Im Beitrag werden einige aktuelle Beispiele aus den Analytiklabors diskutiert, wie z. B. die Anwendung für die Herstellung und RFA-Analytik von Gläsern, eine Feinwäge-Robotik für 10-L-Gaszylinder im Rahmen der Herstellung von Primärnormalen oder die Automatisierung von Probenpräsentationen für optische Spektroskopie und chemical Imaging. Auch wird kurz auf den Einsatz von Speicherprogrammierbaren Steuerungen in der modularen Laborautomation und die Virtualisierung von analytischen Laborrechnern eingengangen. T2 - Industrienetzwerk Smartes Labor am Institut für Energie- und Umwelttechnik e.V. (IUTA) CY - Duisburg, Germany DA - 09.11.2022 KW - Laborautomation KW - Labor-Robotik KW - Automatisierung KW - Smartes Labor PY - 2022 AN - OPUS4-56227 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Höhne, Patrick T1 - Small batch preparation of ready-to-press powder for systematic studies N2 - Efficient studies of scarce or expensive materials require material saving processes. Therefore, a high yield concept for small batch preparation of ready-to-press powder is exemplarily presented for yttria stabilized nano-zirconia (d50 < 50 nm). The concept involves small batch preparation in an ultrasound resonator, dispersant selection based on zeta potential measurements, evaluation of slurry stability using an analytical centrifuge, and preparation of ready-to-press powder by freeze drying. Freeze drying offers key advantages. Process efficiency and high yield above 95 % are independent of sample size. The dried product does not require further mechanical treatment like milling or grinding. Side effects like migration of additives are avoided. An optimized freeze drying process tolerates slurries with moderate stability. Thus, efforts for slurry development can be reduced. Generally, identifying a suitable dispersing agent requires only 3-5 zeta potential measurements. Slurry stability is rechecked using an analytical centrifuge, which also accounts for steric stabilization. An ultrasound resonator is used to disperse the powder without contamination, which becomes critical for small batches. The described route is exemplarily presented for the development of an additive recipe for nano-sized zirconia powder, targeting for good pressing behavior and high green density. Therefore, a variety of binding and lubricating agents were tested. Following the presented route, 80 g zirconia powder were sufficient to conduct a study including slurry development and five sample sets with varying composition, each set comprising five discs (d = 20 mm and h = 2 mm). T2 - 94. DKG Jahrestagung CY - Leoben, Austria DA - 05.05.2019 KW - Fine Powder KW - Slurry KW - Freeze Drying PY - 2019 AN - OPUS4-48293 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - You, Yi T1 - Acoustic Ion Manipulation (AIM) N2 - The precise control of gaseous ions is a cornerstone in ion-based spectrometry and other disciplines such as materials processing. Traditional high-pressure ion optics rely on electrostatic and magnetic fields that often demand the use of intense electric fields, radio frequency activation, complex geometrical arrangements, or partially transmissive grids. Consequently, the efficiencies of such devices tend to be low or they require large footprints, as ion motions under ambient conditions are governed aerodynamically by collisions and fluid dynamics. However, from a different perspective and holistic reasoning, the limitations posed by collisions, aerodynamics, and other factors that hinder ion control in the open-air suggested an innovative direction for ion manipulation. Our study introduces a novel method that employs low-power standing acoustic waves to effectively manipulate ion beams. We observe that ions distinctively prefer traveling through areas of static pressure within the acoustic field, identified as "nodes." In contrast, neutral gases are unaffected by the acoustic field structure and continue to move along a straight trajectory. We have named this method Acoustic Ion Manipulation (AIM). Initial studies demonstrated selective and efficient manipulations of ion with AIM, including gating, redirection, regional dispersion, and focusing. This technique broadens the scope of ion manipulation strategies at high pressures while enriching our fundamental understanding of ion-acoustic kinetics. The potential applications of this method are vast, promising significant advancements in the fields of analytical chemistry, environmental science, and beyond. T2 - ANAKON 2025 CY - Leipzig, Germany DA - 10.03.2025 KW - Acoustic ion manipulation KW - Mass spectrometry PY - 2025 AN - OPUS4-64110 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Li, Xunyu T1 - Atomic Isotope Analysis of Lithium with Spatial Heterodyne Spectrometry and Lineshape Recovery through Deconvolution N2 - A spatial heterodyne spectrometer (SHS) was combined with a reduced-pressure glow discharge to demonstrate the analytical utilization of high resolving-power spectral analysis for atomic isotopes. In the experimental illustrations, we will demonstrate the spectra for the lithium isotope ratio through the D-lines featuring 6Li and 7Li. The SHS utilized in our setup boasts single-digit picometer resolution, enabling the precise discrimination of three separate spectral bands in real-time. To further enhance the spectral quality and improve quantification accuracy, we established an innovative approach to recover the natural lineshape, avoiding interferences from the instrumental function that broadens fine features. By understanding the inherent characteristics of an SHS interferogram and leveraging computational capabilities, we will demonstrate the direct extraction of the numerical presentation of the instrumental function from an SHS interferogram; this instrumental function was used for spectral data processing that enables significant improvements in spectral resolution through deconvolution algorithms. The resulting high-quality spectra enabled precise quantitative determination of lithium concentrations and isotope ratios. We aim to showcase the procedures involved in fine-tuning an SHS platform, along with software design strategy to track real-time spectral variations. Meanwhile, the concept of the lineshape recovery through deconvolution will also be discussed. Furthermore, atomic lithium spectra featuring various isotope compositions will be presented to highlight the potential of SHS in real-life applications. T2 - SCIX 2024 Conference CY - Raleigh, NC, USA DA - 20.10.2024 KW - Spatial Heterodyne Spectrometry KW - High-Resolution Spectrometry KW - Isotopic Analysis KW - Line Shape Recovery KW - Instrumental Function PY - 2024 AN - OPUS4-62138 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Magkos, Sotirios T1 - The DIRECTT algorithm: A promising alternative for Computed Tomography reconstructions N2 - The DIRECTT (Direct Iterative REconstruction of Computed Tomography Trajectories) algorithm represents a promising alternative to conventional algorithms, such as the Filtered Backprojection (FBP) or the Algebraic Reconstruction Technique (ART), by overcoming restrictions associated with them. Such restrictions include the limited spatial resolution achieved through FBP due to Nyquist‘s sampling theorem, the inability of FBP to perform a quality reconstruction when projections are missing, and the excessive computing time needed for ART. T2 - CINEMAX IV Summer School CY - Toreby, Danmark DA - 27.08.2018 KW - Computed tomography KW - Reconstruction algorithm KW - Spatial resolution PY - 2018 AN - OPUS4-46448 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hufgard, Josefin T1 - Use Your Time (Domain) Wisely: Streamlined Analysis of Complex Mixtures with Pulsed-Laser Techniques N2 - This study aims to streamline complex mixture analysis through the parallel ionization of all analytes without extensive preprocessing. Here, pulsed laser ablation of single droplets is used with modified cross-correlation, a phase-sensitive algorithm. This combined method allows contactless chemical investigation with minimal sample pretreatment, as well as the separation of analytes in mixtures and reconstruction of analyte-specific mass spectra. T2 - Future WINS: Corss-sections and interfaces in science, careers, and communication CY - Berlin, Germany DA - 21.11.2024 KW - MS KW - Data analysis KW - Laser ablation PY - 2024 AN - OPUS4-62124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - Was kann die Neutronenbeugung für die ZfP tun? N2 - Neutronenbeugung hat verschiedenste Anwendungen, die auf die eigenartigen physikalischen Eigenschaften der Neutronen berühen. Während die Beugungstechniken wie z.B. die klassische Pulverbeugung, die Kleinwinkelstreuung und die Texturanalyse besonders für die Materialcharakterisierung nutzbar sind, setzt sich die Neutronenbeugung als zerstörungsfreies Verfahren für Eigenspannungsanalyse extrem relevant ein. Allerdings sind nur wenig die Leute, die die Neutronenbeugung in der ZfP Community benutzen. Dieser Vortrag hat das Ziel die Interesse an der Nutzung von einem solchen Grossgerätwerkzeug aufzuwecken und ein Paar impactvolle Anwendungsbeispiele einiger Techniken zu zeigen. Die Bestimmung mikroskopischer mechanischen Eigenschaften von Kompositen (MMC oder CMC), sowie der Mapping von Eigenspannungsfelder in Komponenten werden bearbeitet. Es wird gezeigt, dass Neutronenbeugung grundsätzlich eine zerstörungsfreie Methode für beide die Materialcharakterisierung und die Komponentenintegrität ist, die hohes Potentiell hat, zum Verfahrensportfolio der zerstörungsfreier Prüfung zu gehören. T2 - 381. Sitzung des Arbeitskreises Berlin der DGZfP CY - BAM, Berlin, Deutschland DA - 01.11.2016 KW - Neutronenbeugung KW - Eigenspannungen KW - Kompositen KW - Legierungen KW - Schweißnähte KW - TF Material PY - 2016 AN - OPUS4-38313 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shashev, Yury T1 - Talbot- Lau interferometry with a non- binary phase grating for non-destructive testing N2 - Grating interferometric set-ups have been established in the last decade. They are promising candidates to obtain enhanced image contrast from weakly absorbing micro and nano structures. They are based on X-ray refraction and near-field diffraction using the Talbot effect. At the expense of taking multiple images, Talbot-Lau grating interferometry allows separating the absorption, refraction, and scattering contributions by analysing the disturbances of a phase grating interference pattern. Contrary to other refraction enhanced methods, this technique can be applied using conventional X-ray tubes (divergent, polychromatic source). This makes it attractive to solve typical non-destructive testing problems. We investigated the efficiency of phase gratings, i.e. the visibility (the amplitude of oscillations) upon variation of propagation distance and phase grating rotation around an axis parallel to the grid lines. This grating rotation changes the grating shape (i.e. the distributions of phase shifts). This can yield higher visibilities than derived from rectangular shapes. Our study includes experimental results obtained from synchrotron radiation, as well as simulations for monochromatic radiation. The advantages of Talbot-Lau interferometry are demonstrated at the example of glass capillaries. T2 - WCNDT 2016 CY - Munich, Germany DA - 13.06.2016 KW - Phase grating KW - X-ray phase contrast imaging KW - Talbot- Lau interferomerty KW - Visibility KW - Synchrotron PY - 2016 AN - OPUS4-36625 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pelkner, Matthias T1 - Evaluation of high spatial resolution imaging of magnetic stray fields for early damage detection N2 - Metal magnetic memory (MMM) technique with associated ISO 24497-1:3 is gaining considerable interest in the magnetic NDT community. In contrast to traditional Magnetic Flux Leakage (MFL) testing, the inspection objects are not intentionally magnetized by an external magnetic field. Due to the physical coupling between mechanical stress and magnetization of ferromagnetic materials, it is assumed that the distribution of the residual MFL correspond to the internal stress of the specimen, or in the most general sense, to a degradation of the material. Usually, MMM measurements are performed by relatively bulky magnetic inspection sensors. The evaluation of local magnetic field distribution is limited thereby. Highprecision GMR (Giant Magneto Resistance) measurements in the micrometer regime can provide a higher degree of information due to better spatial resolution. We present a concise summary of studies on the correlation of magnetic structure and microstructure of steels. In particular, we compare residual stress measurements in S235JRC steel welds by means of neutron diffraction with high resolution magnetic field mappings. Results indicate a qualitative correlation between residual stresses and local stray field variation. In addition, stray field measurements of plastically deformed specimens for quasi-static and cyclic loading cases are discussed. The present study concludes that GMR sensors can detect inhomogeneous plastic deformations of S235JR steel in a very early stage, without specific signal processing according to the ISO 24497-1:3. T2 - QNDE - Review of Progress in Quantitative Nondestructive Evaluation CY - Atlanta, Georgia, USA DA - 18.07.2016 KW - NDT KW - MMM KW - GMR PY - 2016 AN - OPUS4-37101 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Bernd R. T1 - Hochauflösende, schnelle Materialcharakterisierung - Zerstörungsfeie Prüfung mittels Röntgenrefraktion N2 - Materialcharakterisierung von CFK-Werkstoffen mittels Röntgen-Refraktion T2 - CCeV-Veranstaltung 3er-AG CY - Augsburg DA - 04.03.2016 KW - CFK KW - Röntgen-Refraktion KW - Faser-Matrix Enthaftung PY - 2016 AN - OPUS4-35666 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bresch, Sophie T1 - Pressure assisted sintering of tape cast calcium cobaltite N2 - Thermoelectric materials can convert waste heat directly into electrical power by utilizing the Seebeck effect. Calcium cobaltite Ca3Co4O9 is a promising p-type oxide thermoelectric material for applications between 600 °C and 900 °C in air. The properties and morphology of Ca3Co4O9 are strongly anisotropic because of its crystal structure of alternating layers of CoO2 and Ca2CoO3. The electrical conductivity is for example 13.5 times higher in a/b-direction than in c-direction. By aligning the plate-like grains, the anisotropic properties can be assigned to the component. Hot-pressing of tablets is a well-known technology for grain alignment of Ca3Co4O9 and increases the thermoelectric properties in a/b-direction remarkably. It also increases the relative density. However, hot-pressing of tablets is limited by the tablet size. An interesting alternative for larger components is the pressure assisted sintering of panels from tape casted layers. Tape casting already leads to a grain alignment during green body forming. By combining tape casting and pressure assisted sintering (50 kN maximum force) of Ca3Co4O9, high densities and high thermoelectric properties can be reached for large components up to 200 mm edge length. Ca3Co4O9 was successfully tape casted with the doctor blade technique (binder: polyvinyl butyral, organic solvent). Several layers of tape were stacked and laminated to 5 cm x 5 cm panels. These panels were sintered with different applied pressures in a LTCC sintering press with combined in-situ shrinkage measurement. Pressure-less sintered panels have a 2.5 times higher electrical conductivity at room temperature than test bars with randomly orientated particles. By applying a uniaxial pressure of 10 MPa during sintering, the electrical conductivity increases by the factor of 6 compared to the pressure-less sintered panels. About 40 % linear shrinkage are reached in pressing direction. The Seebeck coefficient (S25 °C=146 μV/K) and the electrical conductivity (σ25 °C=15100 S/m) are in good agreement with the values published in literature for hot-pressed tablets. T2 - 15th Conference & Exhibition of the European Ceramic Society CY - Budapest, Hungary DA - 09.07.2017 KW - Thermoelectrics KW - Pressure assisted sintering PY - 2017 AN - OPUS4-41026 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Powierza, Bartosz T1 - Water Migration in One-Side Heated Concrete: 4D In-Situ CT Monitoring of the Moisture-Clog-Effect N2 - In order to study damage in concrete exposed to fire, a series of continuous X-ray computed tomography (CT) measurements were performed on a concrete sample heated, in-situ, on one side. The water migration relative to time and 3D space and, in particular, the dynamic condensation and vaporization of water droplets in the pores was quantified. This approach shows significant potential for further investigation of fire-related concrete damage. T2 - 8th Conference on Industrial Computed Tomography (iCT 2018) CY - Wels, Austria DA - 06.02.2018 KW - CT KW - X-ray KW - In-Situ KW - Pores KW - Heated Concrete KW - Water Migration KW - Fire PY - 2018 AN - OPUS4-46381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas T1 - In-operando chracterisation of PEMFCs using synchrotron X-ray radiography and tomography T2 - 7th Joint BER II and BESSY II User Meeting CY - Berlin, Germany DA - 2015-12-09 PY - 2015 AN - OPUS4-35172 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Shashev, Yury T1 - Performance optimization of phase grating in parallel beam for grating interferometry T2 - 7th Joint BER II and BESSY II User Meeting CY - Berlin, Germany DA - 2015-12-09 PY - 2015 AN - OPUS4-35170 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cabeza, Sandra T1 - Characterization of Residual Stress State on Inert Gas Welded Joints by Neutron Diffraction at E3 line T2 - BER Users Meeting CY - Berlin, Germany DA - 2015-12-11 PY - 2015 AN - OPUS4-35128 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Vogl, Jochen T1 - Preparation of an absolute isotope reference material for magnesium T2 - CCQM, IAWG Meeting CY - Tsukuba, Japan DA - 2014-10-14 PY - 2014 N1 - Geburtsname von Mieller, Björn: Brandt, B. - Birth name of Mieller, Björn: Brandt, B. AN - OPUS4-31559 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hothan, Sascha T1 - Lösungsansätze für neue Herausforderungen im konstruktiven baulichen Brandschutz N2 - Der Klimawandel und die zunehmende Ressourcenknappheit stellen Herausforderungen dar, die in Zukunft grundlegende Anpassungen in der Art des Umgangs mit Rohstoffen, Energie und des Wirtschaftens an die Gesellschaft stellen werden. In der Leichtbaustrategie der Bundesregierung wird zusammenfassend festgestellt, dass der fortschreitende Klimawandel Technologien erfordert, die die Transformation der Wirtschaft, eine ressourcenschonende Wertschöpfung und eine nachhaltige und resiliente Rohstoffversorgung sicherstellen. Aus diesen für alle Wirtschaftszweige sehr allgemein formulierten Anforderungen und vor dem Hintergrund eines wachsenden Bedarfs schnell verfügbarer Bausubstanz, lassen sich konkrete Anforderungen für das Bauwesen ableiten. Es geht um die Reduktion des Ressourcenverbrauchs für die Errichtung und den Betrieb neuer Gebäude sowie die Nach- und Weiternutzung bestehender Bausubstanz. In der Bundesanstalt für Materialforschung und -prüfung (BAM) wurde im Themenfeld Infrastruktur das Aktivitätsfeld Leichtbau ins Leben gerufen, das die Forschungsaktivitäten zum Leichtbau bündelt. Im vorliegenden Beitrag werden ausgewählte Projekte.in Bezug auf den konstruktiven baulichen Brandschutz vorgestellt und die besonderen Herausforderungen verdeutlicht sowie die daraus abgeleiteten technischen Lösungsmöglichkeiten aufgezeigt. T2 - Bauphysikertreffen 2025 -- Hochschule für Technik Stuttgart CY - Stuttgart, Germany DA - 28.11.2025 KW - Brandschutz KW - Leichtbau PY - 2025 AN - OPUS4-65370 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Genga, R. M. T1 - Enhanced Fe and Ni bonded NbC Laser Surface Engineered based Hardmetals: Alternative Cutter Materials for Electric Vehicle Applications N2 - The efforts to substitute both tungsten carbide (WC) and cobalt (Co) has gained prominence in recent years due to the classification of Co as a carcinogen and the classification of Co and W as critical raw materials in the EU as well as within regulations of the U.S. National Toxicology Program. In this study, substitution of both WC and Co with advanced hardmetals consisting of NbC with Ni and Fe-based metal binders are investigated for their use of machining of metals used electric vehicle manufacturing. The developed NbC-Ni/Fe based hardmetals employ a Machining Property Led Tailored Design (MPLTD) approach. This reverse engineering strategy uses data from machining performance to guide the development of microstructural, mechanical, and behavioral properties. Four advanced NbC-based hardmetals were produced, two with Ni-based binders and two with Fe-based binders, along with two reference materials for comparison (WC-Co and straight NbC-12Ni). Hardmetals were characterized using field emission scanning electron microscopy (FE-SEM), annular dark-field scanning transmission electron microscopy (ADF-STEM), Vickers hardness, fracture toughness, and elastic moduli. Cutting tool inserts were manufactured from the developed hardmetals and enhanced using femto-second laser surface engineering. The inserts’ performance was evaluated through face milling tests on AZ31 automotive magnesium alloy, providing insights into their suitability for high-demand industrial applications. T2 - 21. Plansee Seminar CY - Reutte, Austria DA - 01.06.2025 KW - Niobium carbide KW - Alternative binders KW - Alternative hard phases KW - Face milling KW - AZ31 magnesium alloy PY - 2025 AN - OPUS4-65381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Theiler, Géraldine T1 - Tribological behavior of polymeric materials in hydrogen N2 - In this talk, an overview of BAM research activities related to Hydrogen is given with a brief presentation of the Competence Center H2Safety@bam. The second part focuses on current projects dealing with the tribological behavior of polymeric materials in Hydrogen. In particular, results regarding the performances of PTFE -free and sustainable materials are given and promising candidates are suggested along with friction mechanisms. T2 - International Hydrogen Energy Development Forum & HYDROGENIUS SYMPOSIUM 2025 CY - Kyushu, Japan DA - 17.12.2025 KW - Hydrogen KW - Friction KW - Wear KW - PTFE-free KW - Sustainable material PY - 2025 AN - OPUS4-65364 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kunji Purayil, Sruthi Krishna T1 - Multimodal Deep Learning Framework for Crack Segmentation in Complex Components Using Robot-Assisted Laser Thermography N2 - Crack detection and segmentation in complex components are critical for maintaining the structural integrity and reliability of systems operating under extreme conditions, such as turbine blades in energy and aerospace applications. The integration of automated multimodal imaging-based non-destructive testing (NDT) with deep learning provides a promising path towards precise and automated defect characterization. In this study, a hybrid multimodal deep learning framework is proposed, combining the advantages of an unsupervised generative adversarial network (GAN) and a supervised U-Net segmentation model for comprehensive crack detection and quantification. The unsupervised multimodal GAN performs data fusion by integrating complementary features from high-resolution thermal and RGB images acquired using a robot-assisted flying laser-line thermography system. This data fusion improves the contrast and representation of surface and sub-surface cracks by leveraging spectral features across multiple imaging modalities. The GAN is trained to reconstruct crack free images and difference between the generated image and real crack image generates an error map that highlights the cracks. The unsupervised approach helps in reducing the need for manual labeled data and generalizes well across different surface conditions. The error maps from GAN are subsequently processed by a U-Net-based segmentation model trained on labeled datasets to achieve precise pixel-level crack localization and morphological estimation. The use of laser thermography induces localized heating on the component surface, providing transient thermal responses that make subtle cracks and defects visible beyond the limits of visual imaging. Experimental validation demonstrates that the proposed hybrid GAN–U-Net framework achieves significantly improved crack detection accuracy and segmentation performance compared to single modal NDE imaging, and data processing based on traditional threshold-based methods. This work underscores the potential of combining unsupervised multimodal fusion with supervised image segmentation to establish a new framework that helps in building automated, data-driven, and robot-assisted NDT systems for intelligent inspection and structural health monitoring of industrial components. T2 - NDE 2025 CY - Mumbai, India DA - 11.12.2025 KW - Non-destructive Testing KW - Infrared Thermography KW - Laser KW - Data Fusion KW - Multimodal Imaging KW - NDE 4.0 PY - 2025 AN - OPUS4-65304 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hirsch, Philipp Daniel T1 - Robotic-assisted 3D scanning and laser thermography for crack inspection on complex components N2 - The integration of automation and robotics into inspection processes has marked a transformative shift in the evaluation of complex components. This study presents a novel approach employing robotic-assisted laser thermography for the automated identification and in-depth analysis of cracks in these intricate structures. This method not only streamlines the inspection process but also eliminates the need for numerous manual steps and the use of chemicals associated with traditional methods such as dye penetrant testing. With the increasing com-plexity of components, this is an important step, especially with regard to additively manufactured components, in order to be able to guarantee component safety for a long lifecycle. T2 - 17th Quantitative InfraRed Thermography Conference (QIRT) CY - Zagreb, Croatia DA - 01.07.2024 KW - Robot KW - Flying line KW - Crack detection KW - Robot path planning KW - Thermography PY - 2024 AN - OPUS4-60914 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hassenstein, Christian T1 - Automatisierte Bahnplanung für robotergestützte Ultraschallprüfung mit Arrayprüfköpfen N2 - In der automatisierten Ultraschallprüfung von Komponenten mit komplexen Oberflächengeometrien werden zur Führung des Prüfkopfes zunehmend 6-Achsen-Roboter erprobt. Diese stellen die notwendige Automatisierbarkeit und Flexibilität bereit, um die lokal senkrechte Einschallung sicherzustellen. Durch den Einsatz von linearen Arrays und bildgebenden Verfahren können die Bilder oder die daraus extrahierten Merkmale zu einer Rekonstruktion in 3D zusammengesetzt werden. Die Anforderungen an die Prüfbahnen für die bildgebende Array-Ultraschallprüfung gehen dabei über konventionellen Bahnplanungsprogramme hinaus. Es wird ein Prozess vorgestellt, der Roboterbahnen auf der Grundlage des 3D-Modells von Körpern mit doppelt gekrümmter Oberfläche unter Berücksichtigung der Prüfparameter erzeugt. Hierbei wird zum einen die senkrechte Prüfkopfstellung und zum anderen eine optimale Abdeckung der Oberfläche realisiert. Dabei wird die lokale Oberflächengeometrie beachtet, da diese das Reflexionsverhalten beeinflusst und sich daher auf die optimale Verteilung und Orientierung der Prüfpositionen auswirkt. Damit einhergehend erfolgt eine Ablösung von konventionellen Konzepten, die auf linearen Prüfbahnen basieren, welches spannende neue Prüfstrategien eröffnet. T2 - DGZfP-Jahrestagung 2024 CY - Osnabrück, Germany DA - 06.05.2024 KW - Ultraschallprüfung KW - Phased array KW - Automatisierung KW - NDT 4.0 PY - 2024 AN - OPUS4-60590 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kunji Purayil, Sruthi Krishna T1 - Anisotropy investigation of a single crystal superalloy using laser-spot infrared thermography N2 - Thermal property investigation of anisotropic materials such as single crystal superalloys are still in interest of practical and fundamental reasons but remains challenging using conventional testing methods. In this study, a single crystal superalloy is tested using laser-spot thermography, and its thermal anisotropy is investigated. Determining anisotropic thermal conductivity at microscopic scales is challenging, as it appears isotropic at the macroscopic scale. Infrared thermography is one of the best-known techniques for measuring material heat transfer properties and facilitating visualization of temperature distribution through the specimen. The proposed study uses the active thermography method of laser-spot infrared thermography, in which a laser spot is focused onto the sample surface and the thermal response is captured from the surface of the specimen with an infrared camera. A detailed analysis of temperature gradients and heat diffusion patterns aids in the measurement of thermal conductivity values along the sample's different crystallographic directions. The directional bonding characteristics and inherent crystallographic structure of the alloy account for the in-plane thermal conductivities calculated from experimental thermal measurements. The laser-spot thermography method has proven to be an effective tool for mapping the material's thermal conductivity anisotropy with high sensitivity and high spatial and temporal resolution. The investigation into the anisotropy of the material provides an insight into heat flow in the structure and helps in optimizing the design and overall performance of the material system. T2 - 17th Quantitative InfraRed Thermography Conference (QIRT) CY - Zagreb, Croatia DA - 01.07.2024 KW - Infrared Thermography KW - NDT KW - Laser KW - Single crystal superalloy KW - Anisotropy PY - 2024 AN - OPUS4-60663 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kunji Purayil, Sruthi Krishna T1 - Aktive punktweise Laserthermographie zur Bewertung der thermischen Anisotropie in Einkristall-Superlegierungen N2 - Die Untersuchung thermischer Eigenschaften anisotroper Materialien, wie einkristalliner Superlegierungen, ist aus praktischen und wissenschaftlichen Gründen von großem Interesse, sie bleibt jedoch mit konventionellen Testmethoden eine Herausforderung. In dieser Studie wird eine einkristalline Superlegierung mittels aktiver Laserthermografie untersucht, wobei ihre thermische Anisotropie analysiert wird. Die Bestimmung der anisotropen Wärmeleitfähigkeit auf mikroskopischer Ebene ist anspruchsvoll, da das Material auf makroskopischer Ebene isotrop erscheint. In der präsentierten Studie wird die zu untersuchende Materialprobe schrittweise mit einem Laserspot abgerastert, welcher die Probe jeweils lokal erwärmt. Die resultierende thermische Antwort wird anschließend durch Messung der Oberflächentemperaturmit einer Infrarotkamera erfasst. Die Infrarotthermografie gehört dabei zu den bewährtesten Techniken zur Messung der Wärmeübertragungseigenschaften von Materialien und zur Visualisierung von Temperaturverteilungen. Eine detaillierte Analyse der gewonnenen Temperaturgradienten und Wärmeverteilungsmustern dient der Bestimmung der Wärmeleitfähigkeitswerte entlang verschiedener kristallographischer Richtungen der Probe. Die gerichteten Bindungseigenschaften und die kristallographische Struktur der Legierung sind dabei hauptursächlich für die Spanne der berechneten lateralen Wärmeleitfähigkeiten, die aus experimentellen thermischen Messungen abgeleitet wurden. Die Methodik der punktweisen aktiven Laserthermografie hat sich als effektives Werkzeug zur hochsensitiven und hochauflösenden räumlichen und zeitlichen Kartierung der thermischen Leitfähigkeitsanisotropie des Materials erwiesen. Die Untersuchung der Anisotropie des Materials bietet Einblicke in den Wärmefluss innerhalb der Struktur und leistet so einen Beitrag zur Optimierung des Designs und der Gesamtleistung des Materials. T2 - DGZFP Jahrestagung 2025 CY - Berlin, Germany DA - 26.05.2025 KW - Laserpunkt-Thermographie KW - Thermischen Anisotropie KW - ZFP KW - Einkristall-Superlegierungen PY - 2025 AN - OPUS4-63254 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Spitzer, Stefan T1 - BAM-Monitoringkompetenz am Beispiel des Projekts INFUSE - SensoJoint N2 - BAM-Monitoringkompetenz mit Fokus auf das Datenmanagement der realen Beanspruchungen von Betonautobahnen von der definierten Datenerfassung über Datenverwaltung, Datenübertragung bis zur Datenauswertung am Beispiel des Projekts 7183-Infuse. T2 - Workshop Digitaler Zwilling CY - BAM Berlin, Germany DA - 04.06.2018 KW - Monitoring KW - Bitumen KW - Betonautobahnen PY - 2018 AN - OPUS4-45124 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hirsch, Philipp Daniel T1 - Robotergestützte 3D-Scans und Laserthermografie zur Prüfung an komplexen Bauteilen auf Risse N2 - Der Vortrag stellt innovative Ansätze zur Automatisierung von Prüfprozessen durch den Einsatz von Robotik und Laserthermografie vor. Im Fokus steht die robotergestützte Laserthermografie zur Identifikation und Analyse von Rissen in komplexen Bauteilen. Diese Methode ermöglicht eine vollständig automatisierte Rissprüfung, die ohne manuelle Arbeitsschritte und chemische Prüfmittel auskommt und damit eine effiziente Alternative zur klassischen Farbeindringprüfung darstellt. Zusätzlich wird ein automatisiertes 3D-Scanning mittels Linienscanner präsentiert, das eine präzise Rekonstruktion der Bauteilgeometrie erlaubt. Dies ermöglicht die adaptive Korrektur von Abweichungen in der Bauteilaufnahme und bildet die Grundlage für eine flexible Bahnplanung bei Bauteilverformungen. Ein weiterer Schwerpunkt ist die automatisierte Rückprojektion der detektierten Risse auf die Bauteiloberfläche. Diese Technik erlaubt nicht nur eine präzise Lokalisierung, sondern auch eine detaillierte geometrische Analyse der Risse. Durch die Kombination von robotergestützter Laserthermografie, hochpräzisem 3D-Scanning und intelligenter Rückprojektion ergeben sich neue Möglichkeiten für die zerstörungsfreie Prüfung komplexer Bauteile und die Erweiterung potenzieller Anwendungsfelder. T2 - Jahrestagung der Deutschen Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) 2024 CY - Osnabrück, Germany DA - 06.05.2024 KW - ZFP4.0 KW - Automatisierung KW - Roboter KW - Laser KW - Rissprüfung KW - Thermografie PY - 2024 AN - OPUS4-62494 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ziegler, Mathias T1 - How thermographic NDT can contribute to achieving the Sustainable Development Goals N2 - In 2015, the global community adopted the UN 2030 Agenda - a roadmap for the future. The Agenda covers economic, environmental and social aspects of development. They formulated the so-called 17 Sustainable Development Goals (SDGs). And what it means is: We are facing a profound systemic transformation! But the question is: how can we achieve these goals? Of course, each of us can contribute by changing some of our habits. But for us as a research organisation, the answer must be science! There are a number of key technologies that will be needed to manage this change. Our contribution as the NDT community should be to support this global transformation by making it a safe one! And infrared thermography is an integral part of this NDT community and represents one of these key technologies. Of the 17 SDGs, we have identified five SDGs (Goal 7: affordable and clean energy, Goal 9: industry, innovation and infrastructure, Goal 11: sustainable cities and communities, Goal 12: responsible consumption and production, Goal 13: climate action) that we believe we can support in line with our mission. In this paper, four specific examples from BAM (Bundesanstalt für Materialforschung und –prüfung / German Federal Institute for Materials Research and Testing) will be used to show how thermographic NDT can contribute to the achievement of the SDGs. As a first example, we want to establish the quality control of novel, resource-conserving high-temperature additive manufacturing processes by establishing thermography-based in-situ measurement techniques. The aim is to achieve zero-defect manufacturing for all processes involving heat, such as the PBF-LB/M and DED-LB/M processes, which are currently entering industrial mass applications. As a second example, our research is focused on replacing traditional resource-intensive inspection methods such as liquid penetrant or magnetic particle inspection with robotic high-resolution laser thermography, which we call photothermal CT and which will enable fully automated inspection of complex geometries at high speed and high resolution. As a third example, we want to support the energy transition and climate protection as a whole through modern IRT inspection techniques by establishing thermographic inspection of wind turbines, in particular of rotor blades. Such inspections will make wind energy safer to use, enable longer operating times and make it more economical by improving its efficiency. In addition to industrial applications, IRT inspection techniques can be applied to the civil engineering sector to support sustainable infrastructure. Useful application scenarios include the early detection of corrosion under protective coatings and the inspection of concrete coatings found on parking decks, which are mainly applied by hand. T2 - Pan-American Conference for Nondestructive Testing (VIII PANNDT) CY - Niagara Falls, Ontario, Canada DA - 09.06.2025 KW - Thermography KW - Additive manufacturing KW - Wind energy KW - Infrastructure PY - 2025 AN - OPUS4-63523 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kunji Purayil, Sruthi Krishna T1 - Preserving History: Application of Active Thermography for Investigating the Bücker Bü 181 Aircraft N2 - Infrared thermography is a widely recognized non-destructive testing (NDT) method used in material research and defect detection across various industrial applications. Moreover, thermography plays a crucial role in preserving cultural heritage, including historical paintings and buildings. This study focuses on the application of thermography in inspecting the historic Bücker Bü 181 aircraft, which was used in Germany during World War II. Over time, the original appearance of aircraft has often been altered as part of preservation efforts, either before or during their time in museums, leading to deviations from their historically original state. Additionally, the operational history of such objects is frequently undocumented or entirely lost, making it difficult to understand the presence of artifacts and historically significant data. These factors present major challenges in cultural heritage preservation, and destructive methods cannot be used to investigate such invaluable objects. Therefore, thermography is implemented as a non-destructive and contactless examination method. Active flash thermography combined with phase analysis is a powerful tool for evaluating multilayer systems. In this study, multiple layers of old paint on the object posed a challenge in assessing defect conditions and retrieving other critical information beneath the surface coatings. Nevertheless, pulse thermography not only demonstrated its capability to identify defects and markings in multilayered coatings but also provided insights into the internal structure and subsections of the investigated aircraft. T2 - DGZFP Jahrestagung 2025 CY - Berlin, Germany DA - 26.05.2025 KW - Non-destructive testing KW - Infrared thermography KW - Multilayer coatings KW - Cultural heritage KW - Defect detection PY - 2025 AN - OPUS4-63255 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kunji Purayil, Sruthi Krishna T1 - Multispectral fusion-based crack detection using automated laser thermography inspection N2 - Crack detection of complex components is critical for maintaining the integrity and safety of structures across industries such as energy production and aerospace. The integration of multispectral imaging and automatic robot-based non-destructive testing (NDT) marks a significant advancement in the inspection of complex geometries. Multispectral imaging leverages the utilization of image data from different wavelength ranges for enhanced feature extraction and analysis. This paper proposes a novel image fusion model by combining thermal and visual images for the detection of surface and sub-surface cracks of turbine blades in energy production. Our study uses 3D scanning of components using a robot-assisted flying laser line, which measures high-resolution thermal data and RGB images using visual cameras simultaneously. Laser thermography induces a localized heating on the sample, creating a thermal response that highlights cracks and defects that are often undetectable using conventional imaging techniques. Multispectral image fusion models are developed based on an unsupervised generative adversarial network (GAN) for precise crack detection. The model validation is done using experimental data, and it demonstrated high crack detection accuracy compared to conventional single-band imaging methods. This research highlights the new potential for advancing NDT technologies by combining thermal inspection techniques with optical imaging to develop a multispectral inspection approach. T2 - SPIE Defense+Commercial Sensing- Thermosense: Thermal Infrared Applications XLVII CY - Orlando, FL, USA DA - 13.04.2025 KW - Non-destructive testing KW - Infrared imaging KW - NDE 4.0 KW - Multispectral imaging KW - Laser PY - 2025 AN - OPUS4-63050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rabe, Torsten T1 - Drucksintern von hochintegrierten LTCC-Schichtverbunden - Möglichkeiten und Grenzen N2 - In der Keramikfertigung werden verschiedene druckunterstützte Sintertechnologien wie heißisostatisches Pressen, Gasdrucksintern und uniaxiales Heißpressen eingesetzt. Eine Variante des uniaxialen Heißpressens stellt das druckunterstützte Sintern von LTCC-Modulen dar. Es wird mit einem gegenüber dem klassischen Heißpressen deutlich reduzierten Druck von nur etwa 1 MPa operiert. Mit der Einführung der Drucksintertechnik wurde es möglich, großflächige, ebene LTCC-Schichtverbunde ohne laterale Schwindung dicht zu sintern und so eine kostengünstige Fertigung im Nutzen zu realisieren. Mit dem Trend zur Miniaturisierung und Funktionserweiterung von Schaltungsträgern sind Applikationskonzepte entwickelt worden, die eine Integration von Mikrowellen-, Kondensator-, Piezo- und Ferritmaterialien durch Co-Sinterung beinhalten. Kavitäten und Kanäle werden benötigt, um LTCC-Schichtverbunde auch in der Sensorik und Mikrofluidik einzusetzen. Die Umsetzung dieser Konzepte erfordert häufig diffizile Sinterprogramme mit temperaturgesteuerter Einstellung von uniaxialem Druck und Sauerstoffpartialdruck. Basierend auf den Ergebnissen zahlreicher F+E-Vorhaben werden Möglichkeiten und Grenzen der Drucksintertechnologie für die Herstellung dieser LTCC-Schichtverbunde illustriert. Vorgestellt wird ein weiterentwickeltes Drucksinteraggregat. Durch Integration von in-situ Schwindungsmessung sowie Mess- und Regeleinrichtungen für den Sauerstoffpartialdruck stehen erweiterte Möglichkeiten für die Optimierung des Drucksinterprozesses von LTCC-Schichtverbunden zur Verfügung. T2 - Symposium: "Keramische Mehrlagentechnik - Herstellverfahren und Anwendungen" CY - Erlangen, Germany DA - 30.11.2016 KW - Heißpressen KW - Sintern KW - Schichtverbunde PY - 2016 AN - OPUS4-38595 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Campos de Oliveira, Paula T1 - Advancing microstructural characterisation of ceramic cores for aerospace: from state-of-the-art to in-situ synchrotron X-ray computed tomography N2 - Ceramic cores are crucial for manufacturing turbine blades in aircraft engines, creating intricate cooling channels that improve engine efficiency and reduce emissions. During high-temperature casting, the cores undergo significant microstructural changes, including phase transitions, particle rearrangements, and porosity transformations, which can affect their properties and must be carefully controlled. State-of-the-art characterisation techniques for ceramic cores mostly rely on 2D methods, such as scanning and transmission electron microscopy. While valuable, these methods are limited in capturing the 3D complexity of the material. Advances in X-ray computed tomography (XCT) offer a more comprehensive perspective on 3D microstructures, but conventional XCT often lacks the resolution and in-situ capabilities to study microstructural evolution under casting conditions. Synchrotron XCT (SXCT) addresses these limitations, offering high spatial and temporal resolution with features down to 1 µm, enabling in-situ investigations. This study highlights the potential of SXCT, revealing previously unseen 3D microstructural features in ceramic cores, such as agglomeration, porosity evolution, surface reactions, microcracking, and particle orientation. These findings provide a more realistic view of dynamic changes during casting, advancing the understanding of core behaviour. Despite its advantages, SXCT is still rarely used in the field due to challenges such as limited access to synchrotron facilities and sample movement artifacts. Future developments, including high-temperature and vacuum compatible CT setups, could enhance this technique, leading to a better optimisation of ceramics performance. T2 - XIXth Conference of the European Ceramic Society (ECERS 2025) CY - Dresden, Germany DA - 31.08.2025 KW - Synchrotron KW - X-ray Computed Tomography KW - Ceramic core KW - Aerospace KW - Microstructure PY - 2025 AN - OPUS4-64050 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Markötter, Henning T1 - Hard X-Ray Imaging Capabilities at BAMline (BESSY II) N2 - The BAMline at the 3rd generation synchrotron X-ray source BESSY II has been supporting researchers in a wide range of research areas for over 20 years. In addition to materials science, these fields also include biology, cultural heritage, and medicine. Being a non-destructive characterization method, synchrotron X-ray imaging, in particular tomography (SXCT), plays a particularly important role in structural characterization. A recent upgrade of key BAMline equipment expands the imaging capabilities: The upgraded dual multilayer monochromator offers flexibility by providing different energy spectra to optimize flux and energy resolution as desired. Different spectra (8 – 60 keV with ΔE/E 0.01%, 1.5%, 4% and pink beam) can be selected. The upgraded detector (in white beam configuration, equipped with an sCMOS camera) allows the higher flux to be exploited with reduced readout times. Shorter tomographic acquisition times in the range of seconds are now possible. Hence, in-situ and operando examinations are routinely available. An integrated slip ring allows continuous rotation of the sample stage for ease of wiring. The pink beam option allows tomographic observation of processes occurring in the time domain of a few seconds with a resolution down to ~ 1 µm. Different scan methods, optimized for quality and speed are available and discussed. Examples of energy related materials from fuel cell and battery research are shown. An optional end station allows refraction enhanced imaging (synchrotron X-Ray refraction radiography (SXRR) and tomography (SXRCT)). That includes an analyzer Si-crystal in Bragg alignment between sample and detector. This technique obtains sensitivity to smaller structures (cracks, pores) down to a few wavelengths, while obtaining field of view sizes in the range of several mm. Besides medicine (e.g., teeth explants), several applications are found in material science, like studies on diesel particulate filters, ceramics, additively manufactured (AM) alloys and metal matrix composites (MMC). The in-situ capabilities include mechanical load (tension and compression) and heating up to 1100°C. A case study, the microstructural evolution during heat treatment of an AM AlSi10Mg, will be shown. T2 - 15th International Conference on X-Ray Microscopy (XRM 2022) CY - Online meeting DA - 19.06.2022 KW - BAMline KW - X-ray imaging KW - Tomography PY - 2022 AN - OPUS4-55691 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Léonard, Fabien T1 - Synchrotron X-ray computed tomography for assessment of shock tube systems N2 - Shock tube systems are non-electric explosive fuses employed in blasting and demolition applications to trigger the detonation of explosive charges. Their working principle is based on the explosive reaction of a fine powder on the tubing´s inner surface, generating a percussive wave travelling at a velocity of 2,100 m/s along the length of the tube, without destroying it. One of the key aspects of the manufacturing process of these shock tubes is the size and morphology of the explosive powder grains and their distribution on the inner wall of the tube, in order to propagate the shockwave efficiently and reliably. For the first time, synchrotron X-ray computed tomography has been used to characterize non-destructively the explosive powder grains, typically Al/HMX between 10 and 20 μm in size, in terms of morphology and 3D distribution but also to characterise the presence and location of defects within the shock tube walls. T2 - 7th Conference on Industrial Computed Tomography CY - Leuven, Belgium DA - 07.02.2017 KW - Explosive KW - Nonel KW - Shock wave KW - Blasting KW - Energetic systems PY - 2017 AN - OPUS4-39168 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Böttcher, Nils T1 - Low Temperature Tomographic In-Situ and Operando Studies in Energy Research N2 - Using low temperatures empowers in-depth investigations of abuse processes in Li-ion cells. A thermal runaway (TR) can be suppressed also on material level at low temperatures.The rethermalization of a critical damaged cell not always leads to a TR. Using the snyergies at BAM enables now In-depth investigation of low temperature inertisation mechanisms in commercial Lithium-Ion-Batteries. In future the synergies will be used for in-depth investigation of other abuse processes in commercial cells e.g., plating or aeging. T2 - HZB Usermeeting CY - Berlin, Germany DA - 11.12.2024 KW - Lithiumbatteries KW - Thermal Runaway KW - Sychrotron computer tomopgrahy KW - Low temperature PY - 2024 AN - OPUS4-62300 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas T1 - Three-dimensional studies on compressed gas diffusion layers and the water distribution in operating fuel cells using synchrotron X-ray imaging T2 - 222nd Electro Chemical Society Meeting CY - Honolulu, HI, USA DA - 2012-10-07 PY - 2012 AN - OPUS4-27026 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni T1 - The uniaxial tensile response of ß-eucryptite with varying levels of microcracking: experiments and modeling T2 - 38th International Conference & Exposition on Advanced Ceramics & Composites CY - Daytona Beach, FL, USA DA - 2014-01-26 PY - 2014 AN - OPUS4-31315 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas T1 - Pore Structure Analysis of Cordierite Diesel Particulate Filter Materials T2 - HZB User Meeting 2013 CY - Berlin, Germany DA - 2013-12-04 PY - 2013 AN - OPUS4-11399 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn T1 - Reduzierung der Entbinderungstemperatur von keramischen Grünfolien T2 - DKG-Jahrestagung 2013 CY - Weimar, Germany DA - 2013-03-18 PY - 2013 N1 - Geburtsname von Mieller, Björn: Brandt, B. - Birth name of Mieller, Björn: Brandt, B. AN - OPUS4-27872 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -