TY - CONF A1 - Griesche, Axel A1 - Altenkirch, J. A1 - Gibmeier, J. A1 - Beyer, Katrin A1 - Kromm, Arne A1 - Kannengießer, Thomas T1 - Welding problems - Investigations with neutrons of residual stress and of hydrogen diffusion in steels T2 - ESS Workshop "Science Vision for the European Spallation Source - German Perspectives" N2 - We report about investigations of typical material problems in steels. First, residual stresses in and around weld seams with low martensite transition temperature filler material were analyzed w/ and w/o additional transverse tensile load. The investigation was accompanied by x-ray diffraction measurements to track stress-induced phase transitions. Martensite formation during welding under external load yield strain gradients near the surface that improve the integrity of the weld. Further, the residual stress distribution close to laser-treated steel surfaces was analyzed. The method could be improved to reduce analysis artifacts. Finally, hydrogen diffusion in different steels was measured using neutron radiography and subsequent image analysis. Diffusion coefficients were derived by analyzing the time-dependent mass flux. In an outlook we describe the optimal ESS instrumentation from a metallurgist’s point of view. T2 - ESS Workshop "Science Vision for the European Spallation Source - German Perspectives" CY - Bad Reichenhall, Germany DA - 2011-10-10 PY - 2011 UR - http://www.fz-juelich.de/cae/servlet/contentblob/1058986/publicationFile/24649/Griesche_pdf.pdf UR - http://www.fz-juelich.de/sid_BD693DF17F42B3018726EE5C2558C56C/jcns/EN/Leistungen/ConferencesAndWorkshops/ESS/_node.html AN - OPUS4-24464 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Horbach, Jürgen A1 - Meyer, Andreas T1 - Thermodynamics and Correlation Effects on Diffusion in Al-Ni Melts T2 - NIST Diffusion Workshop Series: Multicomponen Diffusion Data and Its Impact on the Materials Design Process: Data Needed; Daa Acquisition; and Data Application T2 - NIST Diffusion Workshop Series: Multicomponen Diffusion Data and Its Impact on the Materials Design Process: Data Needed; Daa Acquisition; and Data Application CY - Gaithersburg, MD, USA DA - 2012-05-03 PY - 2012 AN - OPUS4-25895 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel T1 - World Materials Research Institute Forum - An Introduction T2 - NIST Diffusion Workshop Series: Multicomponen Diffusion Data and Its Impact on the Materials Design Process: Data Needed; Data Acquisition; and Data Application T2 - NIST Diffusion Workshop Series: Multicomponen Diffusion Data and Its Impact on the Materials Design Process: Data Needed; Data Acquisition; and Data Application CY - Gaithersburg, MD, USA DA - 2012-05-03 PY - 2012 AN - OPUS4-25896 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Dabah, Eitan A1 - Kannengießer, Thomas A1 - Hilger, A. A1 - Kardjilov, N. A1 - Manke, I. T1 - Imaging of Hydrogen in Steels using Neutrons T2 - Euromat 2013 T2 - Euromat 2013 CY - Seville, Spain DA - 2013-09-09 PY - 2013 AN - OPUS4-29216 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Dabah, Eitan A1 - Kannengießer, Thomas A1 - Hilger, A. A1 - Kardjilov, N. A1 - Manke, I. T1 - NEUTRON IMAGING OF HYDROGEN IN STEELS T2 - MS&T 2013 Symposium: Applied Neutron Scattering in Engineering and Materials Science Research T2 - MS&T 2013 Symposium: Applied Neutron Scattering in Engineering and Materials Science Research CY - Montreal, Canada DA - 2013-10-28 PY - 2013 AN - OPUS4-29503 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Beyer, Katrin A1 - Kannengießer, Thomas A1 - Schillinger, B. T1 - In-situ observation of hydrogen diffusion in iron using neutron radiography T2 - 3rd FRM II User Meeting N2 - Hydrogen assisted cracking of metals limits the durability of welds and constructions. Still the failure mechanisms are not fully understood, for instance the role of hydrogen mass transport during crack initiation. Measuring the hydrogen concentration as a function of time (and space) would allow to determine diffusion coefficients helping to enlighten this lack of understanding. Therefore, neutron radiography is a valuable tool for measuring in situ hydrogen transport in iron and steels [1]. The influence of grain boundaries on the hydrogen diffusion behaviour can be determined by comparing the diffusion behaviour of samples with e.g. different microstructure. In a first study we investigated in situ the simplest case, the hydrogen effusion out of pure iron (ARMCO) using neutron radiography at ANTARES [2]. Samples were charged electrochemically ex situ with a well defined amount of hydrogen, stored in liquid nitrogen and were then heat treated during a neutron radiography measurement whilst the change of neutron transmission was recorded. For analysis the gray values in the pictures were transformed into concentrations with help of an ex post calibration. Therefore, the experimental temperaturetime profile of the heat treatment has been repeated with identical samples in the home lab and the amount of effusing hydrogen was measured by carrier gas hot extraction. In a first approximation the concentration of hydrogen in the sample can be calculated by subtracting the hydrogen concentration in the atmosphere from the initial one in the sample. We were able to measure hydrogen concentrations as low as 65 wt.ppm. Simultaneously monitoring of hydrogenous sample and hydrogen-free reference allowed for in situ measurement of hydrogen effusion. Sample heating was done by infrared radiation. Diffusion coefficients for hydrogen effusion from iron have been calculated. They coincide fairly with literature data. T2 - 3rd FRM II User Meeting CY - Garching, Germany DA - 2010-10-15 PY - 2010 AN - OPUS4-22835 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Lexow, Jürgen T1 - Research on materials simulation and the promotion of global databases - activities within the world materials research institute forum (WMRIF) T2 - MS&T 2013 Symposium: Material Data and Software Tools Needed to Make MGI and ICME a Reality T2 - MS&T 2013 Symposium: Material Data and Software Tools Needed to Make MGI and ICME a Reality CY - Montreal, Canada DA - 2013-10-28 PY - 2013 AN - OPUS4-29459 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Mente, Tobias A1 - Kannengießer, Thomas A1 - Kardjilov, Nikolay T1 - The debye waller factor for temperature distribution determination in NBEI experiments: a case study for GTAW N2 - We could show in GTAW experiments with steel samples that the attenuation of neutron transmission underneath the welding torch due to the Debye-Waller-effect correlates well with sample temperatures obtained by FE numerical simulations. This would allow principally to determine sample temperatures by measuring the neutron beam attenuation. T2 - ITMNR-9 CY - Buenos Aires, Argentina DA - 17.10.2022 KW - Debye waller factor KW - GTAW KW - Temperature distribution determination PY - 2022 AN - OPUS4-56150 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Pfretzschner, Beate A1 - Kannengießer, Thomas T1 - The influence of hydrogen on strain-induced martensite formation and cracking in SMSS investigated simultaneously by ED-XRD and by X-ray radiography N2 - Die Ergebnisse von in-situ Experimenten am Berliner Elektronenspeicherring (BESSY II) werden vorgestellt. Es wurden Zugversuche an wasserstoffbeladenen und wasserstofffreien supermartensitischen Proben durchgeführt und Diffraktionsspektren und radiographische Bilder aufgenommen. Die energiedispersive Röntgendiffraktion ermöglichte dabei in-situ die dehnungsinduzierte Phasenumwandlung von Restaustenit zu Martensit zu beobachten. Die Radiographiebilder der zerreisenden Probe gaben Einblicke in das Bruchverhalten in Abhängigkeit vom Wasserstoffgehalt. T2 - 4th in-situ Workshop 2021 @ 2nd International Conference on Advanced Joining Processes CY - Sintra, Portugal DA - 21.10.2021 KW - Wasserstoffdegradation KW - Snergiedispersive Röntgendiffraktion KW - Zugversuch KW - Röntgenradiographie KW - Supermatensitischer Stahl PY - 2021 AN - OPUS4-53697 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Mente, Tobias A1 - Kannengießer, Thomas A1 - Kardjilov, N. T1 - The Debye-Waller Factor for Temperature Distribution Determination in NBEI Experiments: A Case Study for GTAW N2 - In Neutron-Bragg-Edge Imaging (NBEI) in situ experiments, we studied the phase transitions in martensitic steel sheets during butt-welding. Gas tungsten arc welding was used with a motorized torch allowing automated weldments. The austenitization in the heat affected zone underneath the welding head could be clearly visualized. Also, the retransformation into the martensitic phase upon cooling. However, we observed an unexpected additional change in transmission at λ = 0.44 nm that is at 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. With help of temperature field simulations that were calibrated by the reading of anattached thermo couple during welding, we could show that the Debye-Waller factor can produce an additional image contrast. T2 - SNI 2022 CY - Berlin, Germany DA - 05.09.2022 KW - Welding KW - Debys-Waller-Factor KW - Neutron Imaging PY - 2022 AN - OPUS4-55630 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Dabah, Eitan A1 - Kannengießer, Thomas A1 - Hilger, A. A1 - Kardjilov, N. A1 - Manke, I. A1 - Schillinger, B. T1 - MEASURING HYDROGEN DISTRIBUTIONS IN IRON AND STEEL USING NEUTRONS T2 - 10th World Conference on Neutron Radiography (WCNR-10) T2 - 10th World Conference on Neutron Radiography (WCNR-10) CY - Grindelwald, Switzerland DA - 2014-10-05 PY - 2014 AN - OPUS4-31666 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Horbach, J. A1 - Meyer, A. T1 - Influence of thermodynamic forces on diffusion in melts T2 - TMS 2011 N2 - We report about diffusion measurements and molecular dynamic simulations in Al-Ni and Al-Cu melts. Capillary methods were used to measure Ni and Cu self diffusion and to measure interdiffusion. The combination of the capillary set-up with X-ray radiography allowed in-situ detecting of convective contributions to the interdiffusion transport by tracking the time dependence of diffusion. Thus, the determination of the interdiffusion coefficient can be restricted to convection-free experiment times resulting in an increased accuracy of the measured interdiffusion coefficient. Additionally, quasielastic neutron scattering was used to measure convection-free Ni and Cu self diffusion. Molecular dynamics simulations were used to determine all diffusion coefficients and the thermodynamic factor. The comparison between experiment and simulation shows an excellent agreement of the interdiffusion coefficients as a function of temperature. It was found that interdiffusion is enhanced by thermodynamic forces with a maximum around the stoichiometric composition. T2 - TMS 2011 CY - San Diego, CA, USA DA - 2011-02-27 PY - 2011 AN - OPUS4-23340 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel T1 - Diffusion of hydrogen in steels T2 - DLR-Seminar T2 - DLR-Seminar CY - Cologne, Germany DA - 2011-02-15 PY - 2011 AN - OPUS4-23341 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Beyer, Katrin A1 - Kannengießer, Thomas A1 - Solórzano, E. T1 - In-situ measurement of hydrogen diffusion in steels using neutron radiography T2 - DIMAT 2011, 8th International Conference On Diffusion In Materials T2 - DIMAT 2011, 8th International Conference On Diffusion In Materials CY - Dijon, France DA - 2011-07-03 PY - 2011 AN - OPUS4-24312 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Dabah, Eitan A1 - Pfretzschner, Beate A1 - Schaupp, Thomas A1 - Kannengießer, Thomas A1 - Schulz, M. A1 - Kardjilov, N. T1 - Measurement of hydrogen distributions in metals by neutron radiography and tomography N2 - In recent years, the optimization of the imaging stations at research reactors and especially the further development of the neutron detectors allowed the measurement of hydrogen distributions with increasing spatial and temporal resolution at lower detection limits at the same time. Hydrogen has compared to iron a high total neutron cross section, which allows with basic radiographic methods the visualization of hydrogen in two and three dimensions inside the microstructure of components. This enables the in situ measuring of hydrogen mass flows inside cm thick steel samples with a temporal resolution of 20 s as well as the quantitative measurement of hydrogen accumulations at the crack’s inner surfaces in hydrogen embrittled iron samples. For the first time, we detected directly gaseous hydrogen in the crack cavities and we could measure the gas pressure. This new quality of the information on a micrometer scale allows new insights for the analysis of damage mechanisms, e.g. of hydrogen embrittlement. Further, this method is non-destructive and provides local information in situ and in three dimensions with a spatial resolution of 20-30 µm, which is not accessible with common methods as e.g. thermal desorption spectroscopy. In this contribution, we show examples that demonstrate the spatial and temporal resolution of the neutron radiography and tomography method in order to visualize and quantify hydrogen accumulations at cracks. The measurements were performed at the research reactor BER II of HZB in Berlin and at the FRM II reactor of the neutron source Heinz Maier-Leibnitz in Garching. T2 - 2016 International Hydrogen Conference CY - Moran, Wyoming, USA DA - 11.09.2016 KW - Neutron imaging KW - Hydrogen embrittlement KW - Neutron tomography KW - Neutron radiography PY - 2016 AN - OPUS4-37700 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Boateng, Francis A1 - Kromm, Arne A1 - Kannengießer, Thomas A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Real-time X-ray Radiography for Hot Crack Detection during Welding N2 - Fast digital radiography was used to observe the crack development during single pass bead-on-plate gas tungsten arc welding with a minifocus X-ray source and a digital detector array with 75-micrometer pixel size. The sample material were 5 mm thick AlMgSi plates. An acquisition rate of 12 frames per second and an exposure time of 40 ms per frame were used for real-time observation of the hot crack propagation during welding. The basic spatial resolution of the images is about 80 µm. A 3D laminographic reconstruction of the acquired 2D radiographic images gives access to the volumetric extent of the cracks in the welded sample. The parallel use of a high-speed camera during welding allows the real-time inspection of surface cracks. The development of surface cracks was compared with the crack’s distribution in the sample volume and these results were correlated to the used welding parameters. T2 - MS&T 2016 CY - Salt Lake City, Utah, USA DA - 23.10.2016 KW - X-ray radiography KW - Welding KW - Hot crack KW - X-ray imaging KW - Laminography PY - 2016 AN - OPUS4-38069 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Dabah, Eitan A1 - Pfretzschner, Beate A1 - Schaupp, Thomas A1 - Kannengießer, Thomas T1 - Imaging of Hydrogen in Steels with Neutrons N2 - Cold neutrons are predominantly scattered at hydrogen when penetrating hydrogen-charged samples, resulting in a high image contrast between hydrogen and e.g. iron. The used radiographic set-ups consist of a neutron source, state-of-the-art scintillator screens and digital cameras. This allows monitoring diffusive hydrogen fluxes two-dimensionally with 20s temporal resolution. Such hydrogen fluxes can be quantified by using standards with known hydrogen content and similar sample thickness. Neutron tomography generates three-dimensional models of the hydrogen distribution in steel. Such models gain new insight for damage analysis by showing the hydrogen accumulations around cracks and by enabling the hydrogen gas pressure estimation inside cracks. The capabilities and limitations, as well as perspectives of this method will be discussed and illustrated with help of selected examples. T2 - MS&T 2016 CY - Salt Lake City, Utah, USA DA - 23.10.2016 KW - Hydrogen embrittlement KW - Neutron imaging KW - Neutron radiography KW - Neutron tomography PY - 2016 AN - OPUS4-38066 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Dabah, Eitan A1 - Kannengießer, Thomas A1 - Hilger, A. A1 - Kardjilov, N. A1 - Manke, I. A1 - Schillinger, B. T1 - Imaging of hydrogen in steels using neutrons T2 - Sixth Joint BER II and BESSY II User Meeting T2 - Sixth Joint BER II and BESSY II User Meeting CY - Berlin, Germany DA - 2014-12-03 PY - 2014 AN - OPUS4-32186 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Kannengießer, Thomas A1 - Kardjilov, N. A1 - Manke, I. A1 - Schillinger, B. T1 - Messung von Wasserstoffverteilungen in Eisen und Stahl mittels Neutronenradiographie und -tomographie T2 - DACH Jahrestagung 2015 Zerstörungsfreie Materialprüfung T2 - DACH Jahrestagung 2015 Zerstörungsfreie Materialprüfung CY - Salzburg, Austria DA - 2015-05-11 PY - 2015 UR - http://jahrestagung.dgzfp.de/Portals/jt2015/BB/di1c4.pdf AN - OPUS4-33199 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Griesche, Axel A1 - Kannengießer, Thomas A1 - Hilger, A. A1 - Manke, I. A1 - Kardjilov, N. A1 - Schillinger, B. A1 - Schmidt, M. T1 - MEASURING HYDROGEN DISTRIBUTIONS IN IRON AND STEEL USING NEUTRONS T2 - Institutsseminar, Institut für Angewandte Physik und Messtechnik LRT2, Universität der Bundeswehr München T2 - Institutsseminar, Institut für Angewandte Physik und Messtechnik LRT2, Universität der Bundeswehr München CY - Neubiberg, Germany DA - 2015-01-22 PY - 2015 AN - OPUS4-32755 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -