TY - CHAP A1 - Browne, D. A1 - García-Moreno, F. A1 - Nguyen-Thi, H. A1 - Zimmermann, G. A1 - Kargl, F. A1 - Mathiesen, R. H. A1 - Griesche, Axel A1 - Minster, O. ED - Solanki, K. N. ED - Orlov, D. ED - Singh, A. ED - Neelameggham, N. R. T1 - Overview of In situ X-ray studies of light alloy solidification in microgravity T2 - Magnesium Technology 2017 N2 - Gravity has significant effects on alloy solidification, primarily due to thermosolutal convection and solid phase buoyancy. Since 2004, the European Space Agency has been supporting investigation of these effects by promoting in situ X-ray monitoring of the solidification of aluminium alloys on microgravity platforms, on earth, and in periodically varying g conditions. The first microgravity experiment-investigating foaming of liquid metals - was performed on board a sounding rocket, in 2008. In 2012 the first ever X-ray-monitored solidification of a fully dense metallic alloy in space was achieved: the focus was columnar solidification of an Al-Cu alloy. This was followed in 2015 by a similar experiment, investigating equiaxed solidification. Ground reference experiments were completed in all cases. In addition, experiments have been performed on board parabolic flights-where the effects of varying gravity have been studied. We review here the technical and scientific progress to date, and outline future perspectives. KW - Dendritic growth KW - Materials in space KW - Columnar and equiaxed structures PY - 2017 SN - 978-3-319-52392-7 SN - 978-3-319-52391-0 DO - https://doi.org/10.1007/978-3-319-52392-7_80 SN - 2367-1181 SP - 581 EP - 590 PB - Springer CY - Berlin, Heidelberg AN - OPUS4-39442 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 JF - Review of scientific instruments 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 - TY - CONF A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Lück, S. A1 - Schmidt, V. A1 - Hilger, A. A1 - Garcia-Moreno, F. A1 - Manke, I. T1 - Reconstruction of limited view tomography data by DIRECTT T2 - 18th WCNDT - World conference on nondestructive testing (Proceedings) N2 - Incomplete tomographic data sets such as limited view (missing wedge) data represent a well-known challenge for reconstruction algorithms, since they unavoidably lead to substantial image artefacts. Such data sets may occur in industrial computed tomography of limited access (e.g. extended components, fixed objects), directional opacity, limited sample life time or laminographic set-up. We present strategies to effectively suppress the typical elongation artefacts (e.g. lemon-like deformed pores) by our iterative algorithm DIRECTT which offers the opportunity to vary the versatile reconstruction parameters within each cycle. Those strategies are applied to experimental data obtained from metallic foams as well as model simulations. Comparison is drawn to state-ofthe- art techniques (filtered backprojection and algebraic techniques). Further reference is made to reconstructions of complete data sets serving as gold standards. For quantitative assessment of the reconstruction quality adapted techniques based on spatial statistics are introduced. T2 - 18th WCNDT - World conference on nondestructive testing CY - Durban, South Africa DA - 2012-04-16 KW - Computed tomography KW - Limited tomographic data KW - Iterative reconstruction KW - DIRECTT KW - Limited view KW - Missing wedge KW - Spatial statistics PY - 2012 UR - http://www.ndt.net/article/wcndt2012/papers/208_wcndtfinal00208.pdf SN - 978-0-620-52872-6 SP - 1 EP - 9(?) AN - OPUS4-25834 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zabler, S. A1 - Rueda, A. A1 - Rack, A. A1 - Riesemeier, Heinrich A1 - Zaslansky, P. A1 - Manke, I. A1 - Garcia-Moreno, F. A1 - Banhart, J. T1 - Coarsening of grain-refined semi-solid Al-Ge32 alloy: X-ray microtomography and in situ radiography JF - Acta materialia KW - Microtomography KW - Radiography KW - 2D/3D imageanalysis KW - Technical binary alloys KW - LSW PY - 2007 DO - https://doi.org/10.1016/j.actamat.2007.05.028 SN - 1359-6454 SN - 1873-2453 VL - 55 IS - 15 SP - 5045 EP - 5055 PB - Elsevier Science CY - Kidlington AN - OPUS4-20583 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -