TY - JOUR A1 - Ziesche, R. F. A1 - Robinson, J. B. A1 - Markötter, Henning A1 - Bradbury, R. A1 - Tengattini, A. A1 - Lenoir, N. A1 - Helfen, L. A1 - Kockelmann, W. A1 - Kardjilov, N. A1 - Manke, I. A1 - Brett, D. J. L. A1 - Shearing, P. R. T1 - Editors’ Choice—4D Neutron and X-ray Tomography Studies of High Energy Density Primary Batteries: Part II. Multi-Modal Microscopy of LiSOCl2 Cells N2 - The ability to track electrode degradation, both spatially and temporally, is fundamental to understand performance loss during operation of lithium batteries. X-ray computed tomography can be used to follow structural and morphological changes in electrodes; however, the direct detection of electrochemical processes related to metallic lithium is difficult due to the low sensitivity to the element. In this work, 4-dimensional neutron computed tomography, which shows high contrast for lithium, is used to directly quantify the lithium diffusion process in spirally wound Li/SOCl2 primary cells. The neutron dataset enables the quantification of the lithium transport from the anode and the accumulation inside the SOCl2 cathode to be locally resolved. Complementarity between the collected neutron and X-ray computed tomographies is shown and by applying both methods in concert we have observed lithium diffusion blocking by the LiCl protection layer and identified all cell components which are difficult to distinguish using one of the methods alone. KW - Lithium-ion battery KW - Room-temperature KW - Thermal runaway KW - Gas evolution KW - Cells PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-520890 VL - 167 SP - 140509 PB - IOP Science AN - OPUS4-52089 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Oesch, Tyler A1 - Weise, Frank A1 - Bruno, Giovanni T1 - Detection and Quantification of Cracking in Concrete Aggregate through Virtual Data Fusion of X-ray Computed Tomography Images N2 - In this work, which is part of a larger research program, a framework called “virtual data fusion“ was developed to provide an automated and consistent crack detection method that allows for the cross-comparison of results from large quantities of X-ray Computed Tomography (CT) data. A partial implementation of this method in a custom program was developed for use in research focused on crack quantification in Alkali-Silica Reaction (ASR)-sensitive concrete aggregates. During the CT image processing, a series of image analyses tailored for detecting specific, individual crack-like characteristics were completed. The results of these analyses were then “fused” in order to identify crack-like objects within the images with much higher accuracy than that yielded by any individual image analysis procedure. The results of this strategy demonstrated the success of the program in effectively identifying crack-like structures and quantifying characteristics, such as surface area and volume. The results demonstrated that the source of aggregate has a very significant impact on the amount of internal cracking, even when the mineralogical characteristics remain very similar. River gravels, for instance, were found to contain significantly higher levels of internal cracking than quarried stone aggregates of the same mineralogical type. KW - X-ray Computed Tomography (CT) KW - Alkali-Silica Reaction (ASR) KW - Crack Detection KW - Damage Quantification KW - ASR-Sensitive Aggregate PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-512170 VL - 13 IS - 18 SP - Paper 3921 PB - MDPI CY - Basel, Switzerland AN - OPUS4-51217 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas A1 - Trappe, Volker A1 - Müller, Bernd R. A1 - Bruno, Giovanni T1 - Evolution of CFRP stress cracks observed by in situ X-ray refractive imaging N2 - Modern air-liners and rotor blades of wind turbines are basically made of fiber reinforced plastics (FRP). Their failure heavily impairs the serviceability and the operational safety. Consequently, knowledge of the failure behavior under static and cyclic loads is of great interest to estimate the operational strength and to compare the performance of different materials. Ideally, the damage evolution under operational load is determined with in-situ non-destructive testing techniques. Here, we report on in-situ synchrotron X-ray imaging of tensile stress induced cracks in carbon fiber reinforced plastics (CFRP) due to inter fiber failure. An in-house designed compact-tensile testing machine with a load range up to 15 kN was integrated into the beam path. Since conventional radiographs do not reveal sufficient contrast to distinct cracks due to inter fiber failure and micro cracking from fiber bundles, the Diffraction Enhanced Imaging technique (DEI) is applied in order to separate primary and scattered (refracted) radiation by means of an analyzer crystal. In the laboratory, scanning X-ray refraction topography of CFRP has been applied long before but it comes along with several disadvantages: the long total measuring time hampers real time (in-situ) measurements and the required small beam size hinders end-to-end imaging. The introduced technique overcomes both drawbacks. Imaging and tensile test rig are run unsynchronized at the greatest possible frame rate (0.7 s-1 at 28.8 µm pixel size) and smallest possible strain rate (5.5∙10-4 s-1). For 0°/90° non-crimped fabrics (ncf) the first inter fiber cracks occurred at 380 MPa (strain 0.7 %). Prior to failure at about 760 MPa (strain 2.0 %) we observe the evolution of a nearly equidistant 1 mm grid of cracks running across the entire sample in the fully damaged state before total failure. T2 - 41st Risø International Symposium on Materials Science - Materials and Design for Next Generation Wind Turbine Blades CY - Online meeting DA - 07.09.2020 KW - X-ray refraction KW - Diffraction Enhanced Imaging KW - Carbon Fiber Reinforced Plastics KW - In situ tensile test KW - Crack evolution PY - 2020 AN - OPUS4-51223 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mrkwitschka, Paul A1 - Mieller, Björn A1 - Rabe, Torsten A1 - Markötter, Henning T1 - Machine learning assisted characterization of a Low Temperature Co-fired Ceramic (LTCC) module measured by synchrotron computed tomography. N2 - The 5G technology promises real time data transmission for industrial processes, autonomous driving, virtual and augmented reality, E-health applications and many more. The Low Temperature Co-fired Ceramics (LTCC) technology is well suited for the manufacturing of microelectronic components for such applications. Still, improvement of the technology such as further miniaturization is required. This study focuses on the characterization of inner metallization of LTCC multilayer modules, especially on the vertical interconnect access (VIA). Critical considerations for this characterization are delamination, pore clustering in and at the edge of the VIA, deformation, and stacking offset. A LTCC multilayer consisting of a glassy crystalline matrix with silver based VIAs was investigated by synchrotron x-ray tomography (CT). The aim of this study is to propose a multitude of structural characteristic values to maximize the information gained from the available dataset. Data analysis has been done with the open source software ImageJ as well as several additional plugins. The high-resolution CT data was evaluated through 2D slices for accessibility reasons. The segmentation of all 2000 slices to assess the different regions e.g. pores, silver and glass ceramic was done by a supervised machine learning algorithm. A quantitative evaluation of shape, deformation, and porosity of the VIA with respect to its dimensions is presented and the suitability of the characterization approach is assessed. T2 - 54. Metallographie Tagung CY - Online meeting DA - 16.09.2020 KW - Machine Learning KW - LTCC KW - Synchrotron Tomography PY - 2020 AN - OPUS4-51299 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bruno, Giovanni A1 - Mishurova, Tatiana A1 - Serrano Munoz, Itziar A1 - Ulbricht, Alexander A1 - Fritsch, Tobias A1 - Sprengel, Maximilian A1 - Evans, Alexander A1 - Kromm, Arne A1 - Madia, Mauro ED - Bruno, Giovanni T1 - A Critical Discussion on the Diffraction-Based Experimental Determination of Residual Stress in AM Parts N2 - As opposed to reviewing results on experimental determination of residual stress by diffraction, this paper discusses the open issues when dealing with residual stress determination in additive manufactured parts, in particular those manufactured with laser powder bed fusion techniques. Three points are addressed in detail: (a) the proper determination of the strain-free reference d0, (b) the problem of the determination of the principal axes, and (c) the use of the correct diffraction elastic constants. It is shown that all methods to determine the strain-free reference d0 suffer from caveats, and care must be taken in evaluating the most suitable for the problem being tackled. In addition, it is shown that, in some systems, the principal axes do correspond to the geometrical axes of the specimen, but this needs to be systematically checked, especially in the case of uni- or bidirectional hatching strategies. Finally, the need to experimentally determine the proper diffraction elastic constants is underlined, especially in the case of strongly textured specimens, which again depends on the deposition strategy. T2 - ASTM ICAM 2020 – ASTM International Conference on Additive Manufacturing CY - Online meeting DA - 16.11.2020 KW - Additive Manufacturing KW - Diffraction KW - Residual Stress PY - 2020 U6 - https://doi.org/10.1520/STP163120190148 VL - STP1631 SP - 122 EP - 138 PB - ASTM International CY - USA AN - OPUS4-51347 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lorenzoni, R. A1 - Curosu, I. A1 - Léonard, Fabien A1 - Paciornik, S. A1 - Mechtcherine, V. A1 - Silva, F. A. A1 - Bruno, Giovanni T1 - Combined mechanical and 3D-microstructural analysis of strain-hardening cement-based composites (SHCC) by in-situ X-ray microtomography N2 - The paper presents the results of a series of combined mechanical and in-situ morphological investigations on highstrength strain-hardening cement-based Composites (SHCC). Tension and compression experiments were performed in a CT scanner employing a dedicated mechanical testing rig. The in-situ microtomographic scans enabled correlating the measured specimen response with relevant microstructural features and fracture processes. The microstructural segmentation of SHCC was performed in the framework of Deep Learning and it targeted an accurate segmentation of pores, fibers and aggregates. Besides their accurate volumetric representation, these phases were quantified in terms of content, size and orientation. The fracture processes were monitored at different loading stages and Digital Volume Correlation (DVC) was employed to spatially map the strains and cracks in the specimens loaded in compression. The DVC analysis highlighted the effect of loading conditions, specimen geometry and material heterogeneity at the mesolevel on the strain distribution and fracture localization. KW - Digital Volume Correlation KW - High Strength Concrete KW - In-situ Computed Tomography KW - composites PY - 2020 U6 - https://doi.org/10.1016/j.cemconres.2020.106139 VL - 136 SP - 106139 PB - Elsevier Ltd. AN - OPUS4-51054 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fernández, R. A1 - Bokuchava, G. A1 - Toda-Caraballo, I. A1 - Bruno, Giovanni A1 - Turchenko, V. A1 - Gorshkova, Y. A1 - González-Doncel, G. T1 - Analysis of the Combined Strengthening Effect of Solute Atoms and Precipitates on Creep of Aluminum Alloys N2 - The creep strengthening mechanisms in (age-hardenable) aluminum alloys are analyzed on the basis of a new microstructural study of powder samples, an analysis of a comprehensive revision of creep data from the literature, and a new modeling approach. A strategy based on the strength difference (SD) method to separate the contributions of solid solution atoms and precipitates to creep strengthening is proposed. The new methodology considers the combination of the two contributions avoiding the need of a threshold stress term in the creep equation. The contribution of both precipitates and solid solution is taken into account by means of the analysis of the lattice parameter variation with aging time. For this study, powders of two commercial AA2xxx alloys have been analyzed using diffraction methods. The experimental results are modeled using Lubarda’s approach combined with the SD method. KW - Composites KW - Aluminum alloys KW - Creep models KW - Neutron Diffraction KW - Stress exponent PY - 2020 U6 - https://doi.org/10.1002/adem.201901355 VL - 22 IS - 4 SP - 1901355 PB - WILEY-VCH Verlag AN - OPUS4-51055 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Artzt, K. A1 - Mishurova, Tatiana A1 - Bauer, P.-P. A1 - Gussone, J. A1 - Barriobero-Vila, P. A1 - Evsevleev, Sergei A1 - Bruno, Giovanni A1 - Requena, G. A1 - Haubrich, J. T1 - Pandora’s Box–Influence of Contour Parameters on Roughness and Subsurface Residual Stresses in Laser Powder Bed Fusion of Ti-6Al-4V N2 - The contour scan strategies in laser powder bed fusion (LPBF) of Ti-6Al-4V were studied at the coupon level. These scan strategies determined the surface qualities and subsurface residual stresses. The correlations to these properties were identified for an optimization of the LPBF processing. The surface roughness and the residual stresses in build direction were linked: combining high laser power and high scan velocities with at least two contour lines substantially reduced the surface roughness, expressed by the arithmetic mean height, from values as high as 30 μm to 13 μm, while the residual stresses rose from ~340 to about 800 MPa. At this stress level, manufactured rocket fuel injector components evidenced macroscopic cracking. A scan strategy completing the contour region at 100 W and 1050 mm/s is recommended as a compromise between residual stresses (625 MPa) and surface quality (14.2 μm). The LPBF builds were monitored with an in-line twin-photodiode-based melt pool monitoring (MPM) system, which revealed a correlation between the intensity quotient I2/I1, the surface roughness, and the residual stresses. Thus, this MPM system can provide a predictive estimate of the surface quality of the samples and resulting residual stresses in the material generated during LPBF. KW - Additive manufacturing KW - Ti-6Al-4V KW - Contour scan strategy KW - Surface roughness KW - Melt pool monitoring KW - Residual stress KW - Synchrotron X-ray diffraction PY - 2020 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-510585 VL - 13 IS - 15 SP - 3348 AN - OPUS4-51058 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Risse, S. A1 - Juhl, A. A1 - Mascotto, S. A1 - Arlt, T. A1 - Markötter, Henning A1 - Hilger, A. A1 - Manke, I. A1 - Fröba, M. T1 - Detailed and Direct Observation of Sulfur Crystal Evolution During Operando Analysis of a Li-S Cell with Synchrotron Imaging N2 - Herein, we present a detailed investigation of the electrochemically triggered formation and dissolution processes of α- and β-sulfur crystals on a monolithic carbon cathode using operando high-resolution synchrotron radiography (438 nm/pixel). The combination of visual monitoring with the electrical current response during cyclic voltammetry provides valuable insights into the sulfur formation and dissolution mechanism. Our observations show that the crystal growth process is mainly dictated by a rapid equilibrium between long-chain polysulfides on one side and solid sulfur/short-chain polysulfides on the other side, which is consistent with previous studies in this field. The high temporal and spatial resolution of synchrotron imaging enables the observation of different regimes during the sulfur formation and dissolution process. The appearance of short-chain polysulfides after the first anodic CV peak initiates a rapid dissolution process of α-sulfur crystals on the cathode. The increase in the long-chain lithium polysulfide concentration at the cathode surface during charge results in an increased crystal growth rate, which in turn produces imperfections in α- and β-sulfur crystals. There are strong indications that these defects are fluid inclusions, which may trap dissolved polysulfides and therefore reduce the electrochemical cell capacity. KW - LiS battery KW - Radiography KW - Synchrotron Imaging PY - 2020 U6 - https://doi.org/10.1021/acs.jpclett.0c01284 VL - 11 IS - 14 SP - 5674 EP - 5679 AN - OPUS4-51100 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nerger, Deborah A1 - Hille, Falk A1 - Moosavi, Robabeh A1 - Grunwald, Marcel A1 - Redmer, Bernhard A1 - Kühn, T. A1 - Hering, M. A1 - Bracklow, F. T1 - Post-impact evaluation at RC plates with planar tomography and FEM N2 - Due to the wide range of applications, the easy production and the large field of use, reinforced concrete (RC) is a widespread building material. This variety of applications is reflected in a wide range of physical material properties. Not only therefor it still is a technical challenge to provide all necessary test conditions for experimentally reproducing dynamic effects under impact loading of RC structures. In this paper we present investigations on the thicknesses of RC plates under low and medium high velocity impact loading by a flat-tipped impactor. The planar tomography setup at BAM is used to visualize the impact damage and to characterize the damage features such as cracks, scabbing and spalling. Further, the comparison of tomography results with those of an applied numeric simulation analysis is used to verify the numeric models for future damage prognosis under impact loading. Using the results of both, the tomographic as well as the FE analysis, different damage features were investigated and compared regarding their validity. Crack damage plays a leading part and the significance of summarized crack values as well as their distribution is analyzed. The total damage value but also the determined damage distribution both provide an input for describing damage as a function of the impactor velocity and plate thickness. KW - Reinforced concrete structure KW - Post-impact evaluation KW - Damage characterization KW - Ansys Autodyn KW - Drucker-Prager KW - Planar tomography PY - 2020 U6 - https://doi.org/10.1016/j.matpr.2020.05.671 SP - 1 EP - 10 PB - Elsevier AN - OPUS4-51115 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -