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 - Materials Science & Technology (MS&T) 2013 CY - Montreal, Quebec, Canada DA - 2013-10-27 KW - ICME KW - WMRIF KW - VAMAS KW - M-ERA.net KW - Materials simulation KW - Global databases PY - 2013 SP - 2551 EP - 2554 PB - Curran CY - Red Hook, NY AN - OPUS4-29718 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Griesche, Axel A1 - Solórzano, E. A1 - Beyer, Katrin A1 - Kannengießer, Thomas T1 - The advantage of using in-situ methods for studying hydrogen mass transport: Neutron radiography vs. carrier gas hot extraction N2 - Neutron radiography (NR) is compared with the commonly used carrier gas hot extraction (CGHE) technique. We performed isothermal hydrogen effusion experiments at 623 K to study the mass transport kinetics. The investigated material was technical iron. The quantification of the hydrogen mass flow is done for NR by using concentration standards. The temporal hydrogen concentration evolution in the sample coincides well for both methods, i.e. NR and CGHE, and is in good agreement with literature. The advantages of the NR method are the non-destructive nature of measuring and the in-situ determination of hydrogen concentrations with high spatial and temporal resolution. Remaining hydrogen inside the sample can be identified directly by the NR method. KW - Hydrogen diffusion KW - In-situ KW - Neutron radiography KW - Carrier gas hot extraction KW - Imaging PY - 2013 DO - https://doi.org/10.1016/j.ijhydene.2013.08.145 SN - 0360-3199 VL - 38 IS - 34 SP - 14725 EP - 14729 PB - Elsevier CY - Oxford AN - OPUS4-29413 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beyer, Katrin A1 - Kannengießer, Thomas A1 - Griesche, Axel A1 - Schillinger, B. T1 - Neutron radiography study of hydrogen desorption in technical iron N2 - The purpose of the present study is to show the feasibility of examining hydrogen desorption in technical iron samples using neutron radiography at the ANTARES facility of the FRM II research reactor, Technische Universität München. It has been shown that this method is appropriate for in situ determination of hydrogen Desorption for concentrations as low as 20 ppmH. Experiments were carried out in the temperature range from room temperature up to 260 °C. Measurement was based on direct comparison between electrochemically hydrogen-loaded iron samples and hydrogen-free reference samples at the same temperature. This enables the determination of hydrogen concentration as a function of time and temperature. Ex situ carrier gas hot extraction experiments using the same temperature–time profiles as the neutron radiography experiments have been used to calibrate the greyscale values of the radiographs to defined hydrogen concentrations. It can be stated that hydrogen desorption correlates with sample temperature. KW - Neutron radiography KW - Hydrogen PY - 2011 DO - https://doi.org/10.1007/s10853-011-5450-7 SN - 0022-2461 SN - 1573-4803 VL - 46 IS - 15 SP - 5171 EP - 5175 PB - Springer Science + Business Media B.V. CY - Norwell, Mass. AN - OPUS4-25150 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heuskin, D. A1 - Kargl, F. A1 - Griesche, Axel A1 - Stenzel, C. A1 - Mitschke, D. A1 - Bräuer, D. A1 - Meyer, A. T1 - MSL compatible isothermal furnace insert for high temperature shear-cell diffusion experiments N2 - For long-time diffusion experiments shear-cell techniques offer more favourable terms than the traditional long capillary techniques. Here, we present a further developed shear-cell that enables the measurement of diffusion coefficients up to temperatures of 1600 °C. Hence, diffusion experiments can be carried out at temperatures not accessible until now by conventional capillary or shear-cell techniques. The modified shear-cell, which can contain up to six samples of a total length of 90mm and a diameter of 1.5 mm, is built of 30 shear discs of 3mm thickness each. It is operated in an isothermal furnace insert which can be accommodated in the Materials Science Laboratory of the International Space Station. This provides the opportunity that the shear-cell can be applied to microgravity and to ground-based experiments, respectively. The heater insert with an overall length of 518mm and a diameter of 210mm consists of four heating zones with a total power of 3.5 kW. Temperature homogeneity along the graphite sample compartment is better than 2K at 1600°C. Details of the new design are discussed and results of first successfully performed heating and shearing cycles are presented. KW - Microgravity KW - Diffusion KW - Shear cell KW - Melt KW - Alloy PY - 2011 DO - https://doi.org/10.1088/1742-6596/327/1/012053 SN - 1742-6588 SN - 1742-6596 VL - 327 IS - 012053 SP - 1 EP - 8 PB - IOP Publ. CY - Bristol, UK AN - OPUS4-24994 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kargl, F. A1 - Engelhardt, M. A1 - Yang, F. A1 - Weis, H. A1 - Schmakat, P. A1 - Schillinger, B. A1 - Griesche, Axel A1 - Meyer, A. T1 - In situ studies of mass transport in liquid alloys by means of neutron radiography N2 - When in situ techniques became available in recent years this led to a breakthrough in accurately determining diffusion coefficients for liquid alloys. Here we discuss how neutron radiography can be used to measure chemical diffusion in a ternary AlCuAg alloy. Neutron radiography hereby gives complementary information to x-ray radiography used for measuring chemical diffusion and to quasielastic neutron scattering used mainly for determining self-diffusion. A novel Al2O3 based furnace that enables one to study diffusion processes by means of neutron radiography is discussed. A chemical diffusion coefficient of Ag against Al around the eutectic composition Al68.6Cu13.8Ag17.6 at.% was obtained. It is demonstrated that the in situ technique of neutron radiography is a powerful means to study mass transport properties in situ in binary and ternary alloys that show poor x-ray contrast. KW - Neutron radiography KW - Diffusion KW - Liquid alloys KW - Shear cell PY - 2011 DO - https://doi.org/10.1088/0953-8984/23/25/254201 SN - 0953-8984 SN - 1361-648X VL - 23 IS - 25 SP - 254201-1 EP - 254201-8 PB - IOP Publ. Ltd. CY - Bristol AN - OPUS4-23854 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Beyer, Katrin A1 - Kannengießer, Thomas A1 - Griesche, Axel A1 - Schillinger, B. T1 - Study of hydrogen effusion in austenitic stainless steel by time-resolved in-situ measurements using neutron radiography N2 - The purpose of the present study was to show the feasibility of measuring hydrogen effusion in austenitic stainless steel (1.4301) using neutron radiography at the facility ANTARES of the research reactor FRM II of the Technische Universität München. This method is appropriate to measure in-situ hydrogen effusion for hydrogen concentrations as small as 20 ppmH. Experiments were carried out in the temperature range from room temperature up to 533 K. The measurement principle is based on the parallel comparison of electrochemically hydrogen charged specimen with hydrogen-free reference specimen at the same temperature. This allows the determination of the hydrogen concentration in the specimens as a function of time and temperature. Separate hot carrier gas extraction experiments using the same temperature–time profiles as the radiography experiments have been used to calibrate the grey values of the neutron transmission images into hydrogen concentrations. It can be stated that the hydrogen effusion correlates with the specimen temperature. KW - Hydrogen effusion KW - Austenitic stainless steels KW - Neutron radiography PY - 2011 DO - https://doi.org/10.1016/j.nima.2011.02.010 SN - 0168-9002 SN - 0167-5087 VL - 651 IS - 1 SP - 211 EP - 215 PB - North-Holland CY - Amsterdam AN - OPUS4-23401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Griesche, Axel A1 - Zhang, B. A1 - Solórzano, E. A1 - Garcia-Moreno, F. T1 - Note: X-ray radiography for measuring chemical diffusion in metallic melts N2 - A x-ray radioscopy technique for measuring in situ chemical diffusion coefficients in metallic melts is presented. The long-capillary diffusion measurement method is combined with imaging techniques using microfocus tubes and flat panel detectors in order to visualize and quantitatively analyze diffusive mixing of two melts of different chemical composition. The interdiffusion coefficient as function of temperature and time is obtained by applying Fick’s diffusion laws. Tracking the time dependence of the mean square penetration depth of the mixing process allows to detect changes in the mass transport caused by convective flow. The possibility to sort out convective mass transport contributions from analysis enhances significantly the accuracy compared to the conventional long-capillary diffusion measurement method with postmortem analysis. The performance of this novel diffusion measurement method with x-ray radiography technique is demonstrated by a diffusion experiment in an Al-Ni melt. KW - Diffusion KW - Metal KW - Aluminium KW - Nickel KW - Melt KW - In-situ KW - Radiography KW - Capillary KW - Aluminium-alloys KW - Chemical analysis KW - Chemical interdiffusion KW - Convection KW - Liquid alloys KW - Mass transfer KW - Nickel alloys KW - X-ray apparatus PY - 2010 DO - https://doi.org/10.1063/1.3427256 SN - 0034-6748 SN - 1089-7623 VL - 81 SP - 056104-1 - 056104-3 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-21333 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -