X-ray Laboratory
X-ray radiography is a useful tool for a non-invasive, in situ visualisation and characterization of optically opaque liquid metals and systems. The MHD department has developed two X-ray experimental setups for the visualisation of various phenomena in optically opaque systems. In particular, our X-ray laboratory allows the in situ study of liquid metal batteries, flowing foams, solidification processes and two-phase flows in liquid alloys.
Microfocus X-ray source
Microfocus X-ray tube XWT-225-CT (X-RAY WorX);max. 225 kV, max. 3 mA, max. 350 W
Before May 2024 (the old setup):Phoenix X-ray XS225D-OEM; max. 225 kV, max. 3 mA, max. 320 W
The experiments were monitored by an X-ray radiographic setup delivering images with a spatial resolution of a few microns. A microfocus X-ray tube equipped with a tungsten target has been utilized. After passing the solidification cell the attenuated X-ray beam impinges an X-ray image intensifier (Thales TH9438HX 9”), where the X-rays are converted into a two-dimensional visible light distribution which is recorded by a CCD camera (Kappa CF8/1 BV-3) with a scan rate of 50 half frames per second.
A more detailed analysis of the specific phenomena such as the dendrite sidearm development or fragmentation requires X-ray techniques with a much better spatial resolution (below 1 μm). Synchrotron visualization experiments were performed at the beamline ID19 of the ESRF in Grenoble (France) and the beamline I12 of the Diamond Light Source in Harwell Campus (Didcot, UK).
ISOVOLT X-ray source
Industrial X-ray tube ISOVOLT 450M1/25-55 (GE Sensing & Inspection Technologies); max. 320 kV, max. 10 mA, max. 3200 W
The high power ISOVOLT X-ray source operating with a maximum voltage of 320 kV and a current of 14 mA generates a divergent polychromatic X-ray beam. A scintillation screen (SecureX HB from Applied Scintillation Technologies) is attached to the surface of the container. The non-absorbed part of the X-ray beam comes upon to this scintillation screen where its intensity is converted into visible light. The further imaging is completed with a lens system (Thalheim – Spezial - Optik) and a high-speed video camera (Pco.edge from PCO) equipped with a sCMOS-sensor.
Experiments in the X-ray Laboratory
- In-situ X-ray observations of dendritic solidification
- Controlling Solute Channel Formation using Magnetic Fields
- Liquid metal multiphase flows
- Radiography of liquid metal batteries
Selected publications:
- Timmel, K.; Shevchenko, N.; Fujita, K.; Tsukaguchi, Y.; Eckert, S., X-ray imaging of two-phase flow regimes in a liquid metal swirling downward flow with side wall gas injection, Metallurgical and Materials Transactions B 55(2024), 550-564
- X. Fan et al., Controlling solute channel formation using magnetic fields, Acta Mater, vol. 256, p. 119107, Sep. 2023
- Birjukovs, M., Shevchenko, N. & Eckert, S., An image processing pipeline for in situ dynamic x-ray imaging of directional solidification of metal alloys in thin cells, Exp Fluids 64, 131 (2023).
- N. Shevchenko, J. Grenzer, O. Keplinger, A. Rack, and S. Eckert, Observation of side arm splitting studied by high resolution X-ray radiography, International Journal of Materials Research, vol. 111, no. 1, 2020, pp. 11-16.
- H. Neumann-Heyme et al., Coarsening evolution of dendritic sidearms: From synchrotron experiments to quantitative modeling, Acta Mater, vol. 146, 2018
- N. Shevchenko, O. Roshchupkina, O. Sokolova, and S. Eckert, The effect of natural and forced melt convection on dendritic solidification in Ga-In alloys, J Cryst Growth, vol. 417, 2015
- S. Karagadde, L. Yuan, N. Shevchenko, S. Eckert, and P. D. Lee, 3-D microstructural model of freckle formation validated using in situ experiments, Acta Mater, vol. 79, 2014
- N. Shevchenko et al., Investigations of fluid flow effects on dendritic solidification: Consequences on fragmentation, macrosegregation and the influence of electromagnetic stirring, in IOP Conference Series: Materials Science and Engineering, 2017
- Keplinger, O.; Shevchenko, N.; Eckert, S., Validation of X-ray radiography for characterization of gas bubbles in liquid metals, IOP Conference Series: Materials Science and Engineering 228(2017), 012009
- Timmel, K.; Shevchenko, N.; Röder, M.; Anderhuber, M.; Gardin, P.; Eckert, S.; Gerbeth, G., Visualization of liquid metal two-phase flows in a physical model of the continuous casting process of steel, Metallurgical and Materials Transactions B 46(2015)2, 700-710
- Shevchenko, N.; Boden, S.; Eckert, S.; Borin, D.; Heinze, M.; Odenbach, S.: Application of X-ray radioscopic methods for characterisation of two-phase phenomena and solidfication processes in metallic melts, Eur. Phys. J. Special Topics 220 (2013) 63-77
- S. Boden, S. Eckert, B. Willers, G. Gerbeth; X-ray radioscopic visualization of the solutal convection during solidification of a Ga- 30 wt pct In alloy, Met. Mater Trans A. 39A (2008) 613–623