Imaging Fast Processes in Liquid Metal Foams and Semi-Solid Alloys Using Synchrotron Radioscopy with Spatio-Temporal Micro-Resolution
New X-ray sources of unmatched brilliance, like the superconducting undulator device at ESRF high-energy beamline ID15A, allow for micro-radioscopic investigations with time-resolution up to the micro-second range. Here we present first results of two recent in situ experiments: the visualization of semi-solid metal flow at an acquisition speed 500 frames/s (fps) and the collapse of pore walls in liquid metallic foams investigated at 40,000 fps. Both applications reveal important qualitative and quantitative facts about the dynamic processes in liquid and/or semi-solid metals which were inaccessible until now because of either the limited spatial and/or the limited time-resolution of conventional X-ray devices. Thus, semi-solid slurry is observed to break into small particle clusters when injected at high speed. The event of cell wall collapse in metal foams is found to take ~1–2 ms time, indicating that the dynamics of this system is inertia controlled.
KeywordsBoron Nitride Metal Foam CMOS Camera European Synchrotron Radiation Facility Liquid Volume Fraction
We thank T. Martin, C. Jarnias, M. Peele, M. Di Michiel, V. Honkimäki, T. Weitkamp (ESRF), A. Dieterich, L. Körner (Universität Tübingen), D. Haas, A. Cecilia, T. Rack, H. Schade, A. Volker (ANKA), N. Kardjilov, A. Hilger and G. Choinka (Helmholtz-Zentrum Berlin) for support and fruitful discussions. H. Kropf and C. Förster for the metallographic work. W. Tutsch (PCO AG, Germany) and A. Bridges (Photron Inc., USA) enlightened us about CMOS cameras. Our gratitude further goes to M. Klinger, H. Heimbach and H. Riesemeier from the Federal Institute for Material Testing Berlin (BAM, Germany) for constructing and building the semi-solid experimental setup.
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