TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Quantitative Microstructural Analysis - VAMAS TWA 37 & Liaison with ISO/TC 202 Microbeam Analysis N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects. The recently started project FIB sample processing for TEM is highlighted. Need of more promotion for the engagement of more participants from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed. Further, a short overview of the VAMAS areas of activities is given where Germany is involved. Planed regional VAMAS Workshops in Germany in 2023 are announced. T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 47th Steering Committee Meeting CY - Torino, Italy DA - 18.10.2022 KW - VAMAS KW - Microbeam analysis KW - FIB KW - TEM KW - Sample preparation KW - EBSD PY - 2022 UR - https://amdgroup.inrim.it/events/vamas-sc-meeting-47 AN - OPUS4-56146 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Quantitative Microstructural Analysis - VAMAS TWA 37 & Liaison with ISO/TC 202 Microbeam Analysis N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the identification and launching corresponding VAMAS projects. The ongoing project "FIB sample processing for TEM" is presented in detail. T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 48th Steering Committee Meeting CY - New Delhi, India DA - 9.10.2023 KW - TEM KW - FIB KW - EBSD KW - Sample preparation KW - VAMAS KW - Standardisation KW - Interlaboratory comparisons PY - 2023 UR - https://www.nplindia.org/index.php/amcsnzt_2023/ AN - OPUS4-58538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Quantitative Microstructural Analaysis under VAMAS/TWA 37 N2 - The progress in activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects. Need of more promotion for the engagement of more participants from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed. T2 - Versailles Project on Advanced Materials and Standards (VAMAS) 45th Steering Committee Meeting CY - Online meeting DA - 30.09.2020 KW - VAMAS KW - Microbeam analysis KW - Inter-laboratory comparison KW - EBSD KW - FIB PY - 2020 UR - http://www.vamas.org/ AN - OPUS4-51360 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Payton, E. J. A1 - Agudo Jácome, Leonardo A1 - Nolze, Gert T1 - Phase Identification by Image Processing of EBSD Patterns N2 - Automated electron backscatter diffraction (EBSD) is generally unable to distinguish between multiple cubic phases in a specimen without additional information, such as that obtained by simultaneous energy dispersive X-ray spectroscopy (EDS). Small particles of phases with relatively similar compositions push the limits of phase identification using simultaneous EBSD and EDS, and a mismatch exists between the spatial resolutions of these two techniques due to them having different electron interaction volumes. In a recent paper, the present authors explored using backscatter detectors mounted on top of the EBSD detector to obtain atomic number (Z) contrast images that could be used for phase segmentation in cases where the results from the EBSD and EDS signals remain ambiguous. In the present work, we show that similar information can be obtained from the raw EBSD patterns themselves at higher spatial resolution than was obtained from the backscatter detectors, with the additional advantage of having no spatial mismatch between the data collection grids. KW - Phase identification KW - Backscattered electrons KW - EBSD KW - SEM PY - 2013 DO - https://doi.org/10.1017/S143192761300620X VL - 19 IS - Suppl. 2 SP - 842 EP - 843 AN - OPUS4-37985 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tielemann, Christopher A1 - Busch, R. A1 - Reinsch, Stefan A1 - Patzig, C. A1 - Höche, T. A1 - Avramov, I. A1 - Müller, Ralf T1 - Oriented surface nucleation in diopside glass N2 - Es wird die Texturbildung in kristallisierendem Diopsidglas im Zusammenhang mit der Oberflächenbeschaffenheit der unbehandelten Probe untersucht. Zudem wird der diskutiert, dass es sich bei der Texturbildung in Gläsern höchstwahrscheinlich um ein Nukleationsphänomen handelt welches auf die richtungsabhängige Grenzflächenenergie der kristallisierenden Phase zurückzuführen ist. N2 - Oriented surface crystallization on polished diopside glass surfaces has been studied with scanning electron microscopy, electron backscatter diffraction, transmission electron microscopy and laser scanning microscopy. An orientation preference of [001] parallel to the glass surface was detected for separately growing diopside crystals even as small as 700 nm in size. This finding shows that crystal orientation occurs in the outermost surface layer without crystal-crystal interaction and indicates that the crystal orientation is a result of oriented nucleation. Depending on surface preparation, monomodal crystal orientation distributions with [100] perpendicular to the surface or bimodal distributions with [100] and [010] perpendicular to the glass Surface were detected. It was also shown that the degree of crystal orientation increases with decreasing Surface roughness. The observed orientation of diopside crystals could be explained in terms of the interfacial energies of different crystal faces. KW - Surface energy KW - Glass ceramic KW - Glass KW - EBSD KW - Diopsid PY - 2021 UR - https://www.sciencedirect.com/science/article/pii/S002230932100020X DO - https://doi.org/10.1016/j.jnoncrysol.2021.120661 SN - 0022-3093 VL - 562 PB - Elsevier B.V. AN - OPUS4-53073 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wisniewski, W. A1 - Thieme, C. A1 - Müller, Ralf A1 - Reinsch, Stefan A1 - Groß-Barsnick, S.-M. A1 - Rüssel, C. T1 - Oriented surface nucleation and crystal growth in a 18BaO·22CaO·60SiO2 mol% glass used for SOFC seals N2 - A glass of the composition 37BaO·16CaO·47SiO2 wt% produced on an industrial scale is crystallized at 970 °C for times ranging from 15 min to 2 h. The crystallization at the immediate surface as well as the crystal growth into the bulk are analyzed using scanning electron microscopy (SEM) including energy dispersive X-ray spectroscopy (EDXS) and electron backscatter diffraction (EBSD) as well as X-ray diffraction in the Θ–2Θ setup (XRD). The immediate surface shows the oriented nucleation of walstromite as well as the formation of wollastonite and an unknown phase of the composition BaCaSi3O8. All three phases also grow into the bulk where walstromite ultimately dominates the kinetic selection and grows throughout the bulk due to a lack of bulk nucleation. Walstromite shows systematic orientation changes as well as twinning during growth. A critical analysis of the XRD-patterns acquired from various crystallized samples indicates that their evaluation is problematic and that phases detected by XRD in this system should be verified by another method such as EDXS. KW - Glass KW - Surface nucleation KW - Orientation KW - EBSD PY - 2018 DO - https://doi.org/10.1039/c7ce02008b VL - 20 IS - 6 SP - 787 EP - 795 PB - Royal Society of Chemistry AN - OPUS4-44405 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded T1 - Observations of the deuterium distribution and the structural changes in standard and lean duplex stainless steels by ToF-SIMS and EBSD N2 - Duplex (DSS) and austenitic stainless steels (ASS) are frequently used in many energy related applications. The duplex grade is considered to have outstanding mechanical properties as well as good corrosion resistance. The austenitic phase combines high ductility, even at low temperatures, with sufficient strength, and therefore such materials are applied in storage and transport of high-pressure hydrogen. During service in acidic environments large amounts of hydrogen can ingress into the microstructure and induce many changes in the mechanical properties of the steel. Embrittlement of steels by hydrogen remains unclear even though this topic has been intensively studied for several decades. The reason for that lies in the inability to validate the proposed theoretical models in the sub-micron scale. Among the very few available methods nowadays, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) enables a highly accurate mapping of hydrogen in the microstructure in a spatial resolution below 100 nm. In the present work ToF-SIMS was used as a main tool in order to investigate the effect of deuterium on a duplex microstructure of lean and standard DSSs during and after the electrochemical charging process. Electrochemical charging simulates the service of a component in acidic environments under conditions of cathodic protection that are commonly applied to prevent corrosion reactions. ToF-SIMS after multivariate data analysis (MVA) was combined with high resolution topographic images and electron back-scattered diffraction (EBSD) data to characterize the structural changes. It was observed that the ferritic phase was affected almost identical in all steels whereas in the austenitic phase significant differences were obtained in the lean duplex in comparison to the standard DSS. The obtained results have been compared to similar investigations on a AISI 304L austenitic stainless steel. The advantage of the combined techniques is reflected by the ability to correlate the hydrogen distribution in the microstructure and the resulted phase transformation. T2 - Third International Conference on Metals & Hydrogen CY - Ghent, Belgien DA - 29.05.2018 KW - Data-fusion KW - ToF-SIMS KW - PCA KW - DSS KW - LDX KW - EBSD PY - 2018 AN - OPUS4-45094 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded A1 - Straub, Franka A1 - Nolze, Gert A1 - Wirth, Thomas A1 - Boellinghaus, Thomas A1 - Unger, Wolfgang T1 - Observations of the deuterium distribution and the structural changes in standard and lean duplex stainless steels by ToF-SIMS and EBSD N2 - The use of duplex stainless steels (DSS) in energy related applications is well known. Nowadays, DSSs become more favorable than austenitic steels due to the outstanding mechanical properties, the good corrosion resistance and the lower nickel content.However, the use of the duplex grade in acidic environments such as seawater can lead to a severe degradation in the structural integrity of the steel by hydrogen-induced/assisted cracking mechanisms, which can eventually result in premature failure. Hydrogen assisted degradation and cracking of steels remains unclear even though this topic is intensively studied for more than a century. The main gap lies in the validation of the proposed theoretical models at the sub-micron scale. Industrial and the research communities define a need for an accurate method by which it is possible to image the distribution of hydrogen in the microstructure. Among the very few available methods nowadays, Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) provides precise mapping of hydrogen in the microstructure. Moreover, the powerful combination of ToF-SIMS with multivariate data analysis (MVA), electron backscattered diffraction (EBSD) for providing a the structural information and the use of data fusion techniques can contribute to a better understanding of the hydrogen induced degradation processes in the material. In the present work two types of duplex grades were chosen as a case study (standard and lean DSS). The duplex class, consist of equivalent amounts of ferrite and austenite, was investigated by ToF-SIMS and EBSD during and after electrochemical deuterium charging in order to simulate the service of a component in acidic environments. Deuterium is known to act on the steel similarly to hydrogen and therefore was used as a tracer for hydrogen. The results show that the ferrite was affected almost identical in both steels whereas in the austenitic phase significant differences were observed in the lean duplex in comparison to the standard duplex. The advantage of the combined techniques is reflected by the ability to correlate the hydrogen distribution in the microstructure to the resulted structural changes. T2 - 21st International Conference on Secondary Ion Mass Spectrometry - SIMS21 CY - Krakow, Poland DA - 10.09.2017 KW - ToF-SIMS KW - Duplex-steel KW - EBSD KW - Data-fusion PY - 2017 UR - http://sims.confer.uj.edu.pl/boa_oral.php?id=23 AN - OPUS4-42864 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sobol, Oded A1 - Nolze, Gert A1 - Saliwan Neumann, Romeo A1 - Eliezer, D. A1 - Böllinghaus, Thomas A1 - Unger, Wolfgang T1 - Novel approach to image hydrogen distribution and related phase transformation in duplex stainless steels at the sub-micron scale N2 - The effect of electrochemical charging of hydrogen on the structure of a lean duplex stainless steel LDX 2101® (EN 1.4162, UNS S32101) was examined by both Time-of-Flight secondary ion mass spectrometry and electron back-scatter diffraction. The goal is to correlate hydrogen concentration and induced structural changes. Chemical and structural characterizations were done for the same region at the sample's surface with sub-micron spatial resolution. Regions of interest were varying in size between 50 × 50 μm and 100 × 100 μm. The results show a phase transformation of austenite to mainly a defect-rich BCC and scarcely a HCP phase. The phase transformation occurred in deuterium rich regions in the austenite. KW - Time-of-flight secondary ion mass spectrometry KW - ToF-SIMS KW - Electron backscatter diffraction KW - EBSD KW - Hydrogen-assisted cracking KW - Data fusion KW - Lean duplex stainless steel PY - 2017 DO - https://doi.org/10.1016/j.ijhydene.2017.08.016 SN - 0360-3199 VL - 42 IS - 39 SP - 25114 EP - 25120 AN - OPUS4-42022 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Suárez Ocano, Patricia A1 - Fries, S. G. A1 - López-Galilea, I. A1 - Ruttert, B. A1 - Theisen, W. A1 - Agudo Jácome, Leonardo T1 - Microstructural characterization of the AlMo 0.5 NbTa 0.5 ZrTi refractory complex concentrated alloy N2 - A set of some unexpected and interesting microstructures has put the so-called complex concentrated alloys (CCAs) in the eye of the scientific community and the AlMo0.5NbTa0.5TiZr refractory (r)CCA, aimed at substituting Ni-base superalloys in gas turbine applications, belongs to this alloy family. The AlMo0.5NbTa0.5TiZr rCCA was studied by SEM, EDX, EBSD and TEM, showing the presence of a nanoscopic basket-wave structure inside the grains, with two BCC phases. Additionally, thermodynamic calculations on the AlMo0.5NbTa0.5TiZr alloy were done with two different proprietary databases that anticipate two BCC-disordered phases with distinct constitutions as well as an HCP phase. T2 - Symposium on Advanced Mechanical and Microstructural Characterization of High-Entropy Alloys CY - Bochum, Germany DA - 03.02.2020 KW - High Entropy Alloy KW - EBSD KW - Microstructure Characterization PY - 2020 AN - OPUS4-50729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cios, G. A1 - Winkelmann, A. A1 - Nolze, Gert A1 - Tokarski, T. A1 - Rychlowski, L. A1 - Dan, L. A1 - Bala, P. T1 - Mapping of lattice distortion in martensitic steel—Comparison of different evaluation methods of EBSD patterns N2 - To visualize the varying tetragonal distortions in high carbon martensitic steels by EBSD, two different approaches have been applied on backscattered Kikuchi diffraction (BKD) patterns. A band-edge refinement technique called Refined Accuracy (RA) (Oxford Instruments) is compared with a technique called Pattern Matching (PM), which optimizes the fit to a simulated BKD signal. RA distinguishes between hypothetical phases of different fixed 𝑐∕𝑎, while PM determines a best fitting continuous 𝑐∕𝑎 by projective transformation of a master pattern. Both techniques require stored BKD patterns. The sensitivity of the 𝑐∕𝑎-determination was tested by investigating the microstructure of a ferritic steel with an expected 𝑐∕𝑎 = 1. The influence of the Kikuchi pattern noise on 𝑐∕𝑎 was compared for a single or 40 averaged frames per measuring point, and turned out to be not significant. The application of RA and PM on the martensitic microstructure delivered qualitatively similar maps of 𝑐∕𝑎. The comparison of RA and PM shows that RA is suitably fast and precise during mapping the martensite 𝑐∕𝑎 ratio in analyses of high carbon martensite, especially for fast initial surveys. As RA leads quantitatively to higher noise in 𝑐∕𝑎, the PM analysis can be used for higher precision results. KW - EBSD KW - Steel KW - Martensite KW - Tetragonality KW - Strain PY - 2023 DO - https://doi.org/10.1016/j.ultramic.2023.113824 VL - 253 SP - 1 EP - 11 AN - OPUS4-58158 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nolze, Gert A1 - Tokarski, T. A1 - Cios, G. A1 - Winkelmann, A. T1 - Manual measurement of angles in backscattered and transmission Kikuchi diffraction patterns N2 - A historical tool for crystallographic analysis is provided by the Hilton net, which can be used for manually surveying the crystal lattice as it is manifested by the Kikuchi bands in a gnomonic projection. For a quantitative analysis using the Hilton net, the projection centre as the relative position of the signal source with respect to the detector plane needs to be known. Interplanar angles are accessible with a precision and accuracy which is estimated to be ≤0.3o. Angles between any directions, e.g. zone axes, are directly readable. Finally, for the rare case of an unknown projection-centre position, its determination is demonstrated by adapting an old approach developed for photogrammetric applications. It requires the indexing of four zone axes [uvw]i in a backscattered Kikuchi diffraction pattern of a known phase collected under comparable geometric conditions. KW - Electron backscatter diffraction KW - EBSD KW - Angle measurement KW - Gnomonic projections KW - Kikuchi patterns PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507625 DO - https://doi.org/10.1107/S1600576720000692 VL - 53 SP - 435 EP - 443 AN - OPUS4-50762 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hodoroaba, Vasile-Dan T1 - Liaison report from VAMAS with ISO/TC 202 Microbeam Analysis N2 - The progress in the activities on Microbeam Analysis under VAMAS/TWA 37 is reviewed. Particularly the liaison with the new projects within the ISO technical committee TC 202 is presented and discussed with respect to the possibility of identifying and launching related VAMAS projects/inter-laboratory comparisons. The recently started project FIB sample processing for TEM is presented. Next projects in the pipeline involving EBSD and TKD are shortly announced. The need of more promotion for the engagement of more experts from industry and academia at national, European and international level is highlighted. Also, the competition with the other technical working areas (on 'nano' or materials-related) is critically discussed. T2 - 29th Annual Meeting of ISO/TC 202 Microbeam Analysis CY - Online meeting DA - 28.11.2022 KW - VAMAS KW - ISO/TC 202 KW - Microbeam Analysis KW - EBSD KW - Electron microscopy KW - Thin films PY - 2022 AN - OPUS4-56424 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nolze, Gert A1 - Tokarski, T. T1 - Lattice parameter determination with EBSD. Is that possible? N2 - CALM is software for determining the Bravais lattice type and the resulting lattice parameters from a single Kikuchi pattern. It requires the definition of 4 bands and a single bandwidth from which all other band positions as well as bandwidths are derived. For band detection, it uses the Funk transform, which allows detection of twice as many bands as usual. CALM works for any symmetry and requires low-noise patterns of at least 320x240 pixels. The resulting errors are <2% even for such small patterns, assuming good quality. The relative errors are <0.5%. However, this requires a projection centre position best derived from a sample of a cubic phase in CALM. However, this must have been recorded under identical conditions. Hundreds of Kikuchi patterns of phases with different symmetries were examined. T2 - Institutskolloquium Kassel CY - Online meeting DA - 30.10.2020 KW - Phasenidentifikation KW - EBSD KW - Gitterkonstanten PY - 2020 AN - OPUS4-51813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Winkelmann, A. A1 - Nolze, Gert A1 - Cios, G. A1 - Tokarski, T. A1 - Bala, P. A1 - Hourahine, B. A1 - Trager-Cowan, C. T1 - Kikuchi pattern simulations of backscattered and transmitted electrons N2 - We discuss a refined simulation approach which treats Kikuchi diffraction patterns in electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD). The model considers the result of two combined mechanisms: (a) the dynamical diffraction of electrons emitted coherently from point sources in a crystal and (b) diffraction effects on incoherent diffuse intensity distributions. Using suitable parameter settings, the refined simulation model allows to reproduce various thickness- and energy-dependent features which are observed in experimental Kikuchi diffraction patterns. Excess-deficiency features are treated by the effect of gradients in the incoherent background intensity. Based on the analytical two-beam approximation to dynamical electron diffraction, a phenomenological model of excess-deficiency features is derived, which can be used for pattern matching applications. The model allows to approximate the effect of the incident beam geometry as a correction signal for template patterns which can be reprojected from pre-calculated reference data. As an application, we find that the accuracy of fitted projection centre coordinates in EBSD and TKDcan be affected by changes in the order of 10−3–10-2 if excess-deficiency features are not considered in the theoreticalmodel underlying a best-fit pattern matching approach. Correspondingly, the absolute accuracy of simulation-based EBSD strain determination can suffer frombiases of a similar order of magnitude if excess-deficiency effects are neglected in the simulation model. KW - Electron diffraction KW - EBSD KW - Kikuchi diffraction KW - Pattern matching PY - 2021 DO - https://doi.org/10.1111/jmi.13051 VL - 284 IS - 2 SP - 157 EP - 184 PB - Wiley Online Library AN - OPUS4-53109 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Winkelmann, A. A1 - Nolze, Gert A1 - Cios, G. A1 - Tokarski, T. A1 - Bala, P. A1 - Hourahine, B. A1 - Trager-Cowan, C. T1 - Kikuchi pattern simulations of backscattered and transmitted electrons N2 - We discuss a refined simulation approach which treats Kikuchi diffraction patterns in electron backscatter diffraction (EBSD) and transmission Kikuchi diffraction (TKD). The model considers the result of two combined mechanisms: (a) the dynamical diffraction of electrons emitted coherently from point sources in a crystal and (b) diffraction effects on incoherent diffuse intensity distributions. Using suitable parameter settings, the refined simulation model allows to reproduce various thickness- and energy-dependent features which are observed in experimental Kikuchi diffraction patterns. Excess-deficiency features are treated by the effect of gradients in the incoherent background intensity. Based on the analytical two-beam approximation to dynamical electron diffraction, a phenomenological model of excess-deficiency features is derived, which can be used for pattern matching applications. The model allows to approximate the effect of the incident beam geometry as a correction signal for template patterns which can be reprojected from pre-calculated reference data. As an application, we find that the accuracy of fitted projection centre coordinates in EBSD and TKDcan be affected by changes in the order of 10−3–10−2 if excess-deficiency features are not considered in the theoreticalmodel underlying a best-fit pattern matching approach. Correspondingly, the absolute accuracy of simulation-based EBSD strain determination can suffer frombiases of a similar order of magnitude if excess-deficiency effects are neglected in the simulation model. KW - Electron diffraction KW - EBSD KW - Kikuchi diffraction KW - Pattern matching PY - 2021 DO - https://doi.org/10.1111/jmi.13051 VL - 284 IS - 2 SP - 157 EP - 184 PB - Wiley Online Library AN - OPUS4-53584 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Röhsler, Andreas A1 - Sobol, Oded A1 - Hänninen, H. A1 - Böllinghaus, Thomas T1 - In-situ ToF-SIMS analyses of deuterium re-distribution in austenitic steel AISI 304L under mechanical load N2 - Hydrocarbons fuel our economy. Furthermore, intermediate goods and consumer products are often hydrocarbon-based. Beside all the progress they made possible, hydrogen-containing substances can have severe detrimental effects on materials exposed to them. Hydrogen-assisted failure of iron alloys has been recognised more than a century ago. The present study aims to providing further insight into the degradation of the austenitic stainless steel AISI 304L (EN 1.4307) exposed to hydrogen. To this end, samples were electrochemically charged with the hydrogen isotope deuterium (2H, D) and analysed by scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). It was found that deuterium caused a phase transformation from the original γ austenite into ε- and α’-martensite. Despite their low solubility for hydrogen, viz. deuterium, the newly formed phases showed high deuterium concentration which was attributed to the increased density of traps. Information about the behaviour of deuterium in the material subjected to external mechanical load was gathered. A four-point-bending device was developed for this purpose. This allowed to analyse in-situ pre-charged samples in the ToF-SIMS during the application of external mechanical load. The results indicate a movement of deuterium towards the regions of highest stress. KW - ToF-SIMS KW - Hydrogen KW - Deuterium KW - AISI 304L KW - EBSD PY - 2020 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505142 DO - https://doi.org/10.1038/s41598-020-60370-2 VL - 10 IS - 1 SP - 3611 PB - Nature AN - OPUS4-50514 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fu, B. A1 - Shen, J. A1 - Suhuddin, U. A1 - Chen, T. A1 - dos Santos, J. A1 - Klusemann, B. A1 - Rethmeier, Michael T1 - Improved mechanical properties of cast Mg alloy welds via texture weakening by differential rotation refill friction stir spot welding N2 - Cast magnesium alloys welds produced by refill friction stir spot welding (refill FSSW) show low lap shear strength (LSS) and constantly fail in stirred zone (SZ) shear mode. The cause is most probably related to the heavily textured microstructure. Here, to re-engineer the resulting microstructure, we pro- pose a novel process variant, the differential rotation refill FSSW (DR-refill FSSW). DR-refill FSSW stim- ulates discontinuous dynamic recrystallization and produces a bimodal microstructure with weakened texture. Therefore, the deformation incompatibility between SZ and thermal-mechanically affected zone is avoided. The welds have 50% higher LSS than that of standard refill FSSW welds, and fail in a different failure mode, i.e., SZ pull-out mode. DR-refill FSSW provides a new and effective strategy for improving the performance of spot welds based on microstructural engineering. KW - Refill friction stir spot welding KW - Magnesium Alloy KW - Texture KW - EBSD KW - Plastic deformation PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536885 DO - https://doi.org/10.1016/j.scriptamat.2021.114113 SN - 1359-6462 VL - 203 SP - 114113 PB - Elsevier Ltd. AN - OPUS4-53688 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded T1 - Hydrogen assisted cracking phenomena in duplex stainless steels elucidated by in- and ex-situ ToF-SIMS experiments N2 - In the presented research, the high potential and abilities of secondary ion mass spectrometry (ToF-SIMS) to detect and locally map the hydrogen distribution in two types of duplex stainless steels are shown. The research validates certain proposed mechanisms by combining ToF-SIMS with high-resolution scanning electron microscopy and electron-backscattered diffraction. The combination of data from several techniques on the same region was conducted in this field for the first time by applying data treatment of the ToF-SIMS raw data and data fusion approach. This powerful combination of methods allows reviewing of the occurring processes related to hydrogen assisted cracking. The step beyond the state of the art in this field was gained here by developing permeation and mechanical loading experiments within the ToF-SIMS during chemometric imaging of the hydrogen distribution in the microstructure. The research presents the necessary correlation between the hydrogen distribution and the resulted structural changes, the diffusion behavior in a duplex microstructure and stress induced diffusion of hydrogen by applying external load at the microscale. T2 - 6th WMRIF Early Career Scientist Summit CY - NPL Teddington UK DA - 18.06.2018 KW - ToF-SIMS KW - Duplex stainless steel KW - LDX KW - EBSD KW - Data-fusion PY - 2018 AN - OPUS4-46865 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sobol, Oded A1 - Boellinghaus, Thomas A1 - Wirth, Thomas A1 - Unger, Wolfgang A1 - Eliezer, D. T1 - High resolution ToF-SIMS imaging of deuterium permeation and cracking in duplex stainless steels N2 - Fundamental understanding and elucidation of hydrogen assisted degradation and trapping mechanisms is dependent on sufficient imaging techniques for respective hydrogen interactions, in particular with multi-phase metallic microstructures. The present work shows the progress in elucidating the deuterium behavior in austenitic-ferritic duplex stainless steels under the consideration that deuterium behaves in many ways similarly to hydrogen. A novel combination of deuterium permeation and in-situ Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) imaging technique is compared with post charging ToF-SIMS imaging experiments. As a step beyond state-of-the-art, integration of chemo-metric and high resolution structural characterization techniques with computational multivariate data analysis (MVA) and data fusion is presented. T2 - 2016 International Hydrogen Conference CY - Grand Teton National Park, Jackson Lake Lodge, Wyoming, USA DA - 11.09.2016 KW - DSS KW - ToF-SIMS KW - Data-fusion KW - EBSD PY - 2017 SN - 978-0-7918-6138-7 SP - 407 EP - 415 PB - ASME Press CY - Two Park Ave. New-York, NY 10016, USA AN - OPUS4-42647 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -