Simultaneous X-ray radioscopy/tomography and energy-dispersive diffraction applied to liquid aluminium alloy foams

Jiménez, Catalina; Paeplow, Marlen; Kamm, Paul H.; Neu, Tillmann Robert; Klaus, Manuela; Wagener, Guido; Banhart, John; Genzel, Christoph; García‐Moreno, Francisco

doi:10.1107/s1600577518011657

Cited by 10 publications

(10 citation statements)

References 18 publications

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“…Time-resolved tomography for in situ analyses in materials science has become very popular 35–40 . Systems such as rechargeable batteries 41 , solidifying alloys 15,34,42,43 or evolving metallic foams 35,44–46 are of special interest. Time-resolved radioscopy for very short exposure times (down to 100 ps per image) and 1 Mfps repetition rate is possible 47 , but acquisition is limited to very short periods, thus not allowing to follow longer processes continuously.…”

Section: Methodsmentioning

confidence: 99%

Using X-ray tomoscopy to explore the dynamics of foaming metal

et al. 2019

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The complex flow of liquid metal in evolving metallic foams is still poorly understood due to difficulties in studying hot and opaque systems. We apply X-ray tomoscopy –the continuous acquisition of tomographic (3D) images– to clarify key dynamic phenomena in liquid aluminium foam such as nucleation and growth, bubble rearrangements, liquid retraction, coalescence and the rupture of films. Each phenomenon takes place on a typical timescale which we cover by obtaining 208 full tomograms per second over a period of up to one minute. An additional data processing algorithm provides information on the 1 ms scale. Here we show that bubble coalescence is not only caused by gravity-induced drainage, as experiments under weightlessness show, and by stresses caused by foam growth, but also by local pressure peaks caused by the blowing agent. Moreover, details of foam expansion and phenomena such as rupture cascades and film thinning before rupture are quantified. These findings allow us to propose a way to obtain foams with smaller and more equally sized bubbles.

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Section: Methodsmentioning

confidence: 99%

Using X-ray tomoscopy to explore the dynamics of foaming metal

et al. 2019

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“…A scheme of the setup is shown in Figure 1. A detailed description of the system can be found in the literature [22,23]. Samples of 4 mm × 4 mm × 2 mm size were placed on a steel holder on top of a M-660 rotation stage from Physik Instrumente PI, Karlsruhe, Germany, and heated up to 640 • C at a rate of 3.4 K/s with an infrared (IR) heating lamp of 150 W power.…”

Section: Synchrotron X-ray Radioscopy and Diffractionmentioning

confidence: 99%

The Influence of Alloy Composition and Liquid Phase on Foaming of Al–Si–Mg Alloys

García‐Moreno

Radtke

Neu

et al. 2020

Metals

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The foaming behaviour of aluminium alloys processed by the powder compaction technique depends crucially on the exact alloy composition. The AlSi8Mg4 alloy has been in use for a decade now, and it has been claimed that this composition lies in an “island of good foaming”. We investigated the reasons for this by systematically studying alloys around this composition by varying the Mg and Si content by a few percent. We applied in situ X-ray 2D and 3D imaging experiments combined with a quantitative nucleation number and expansion analysis, X-ray tomography of solid foams to assess the pore structure and pore size distribution, and in situ diffraction experiments to quantify the melt fraction at any moment. We found a correlation between melt fraction and expansion height and verified that the “island of good foaming” actually exists, and foams outside a preferred range for the liquid fraction—just above TS and between 40–60%—show a poorer expansion performance than the reference alloy AlSi8Mg4. A very slight increase of Si and decrease of Mg content might further improve this foam.

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“…The diffraction experiment was performed on the EDDI beamline at the BESSY-II synchrotron, Helmholtz Zentrum, Berlin (Klaus & Garcia-Moreno, 2016;Jime ´nez et al, 2018). The white beam from the beamline's 7 T multipole wiggler was filtered with 10 mm of aluminium to attenuate low-energy photons which could cause sample heating, and to harden the incident X-ray spectrum to higher photon energies.…”

Section: Operando Spatially Resolved Diffractionmentioning

confidence: 99%

An operando spatially resolved study of alkaline battery discharge using a novel hyperspectral detector and X-ray tomography

et al. 2020

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An experimental technique is described for the collection of time-resolved X-ray diffraction information from a complete commercial battery cell during discharging or charging cycles. The technique uses an 80 × 80 pixel 2D energy-discriminating detector in a pinhole camera geometry which can be used with a polychromatic X-ray source. The concept was proved in a synchrotron X-ray study of commercial alkaline Zn–MnO2 AA size cells. Importantly, no modification of the cell was required. The technique enabled spatial and temporal changes to be observed with a time resolution of 20 min (5 min of data collection with a 15 min wait between scans). Chemical changes in the cell determined from diffraction information were correlated with complementary X-ray tomography scans performed on similar cells from the same batch. The clearest results were for the spatial and temporal changes in the Zn anode. Spatially, there was a sequential transformation of Zn to ZnO in the direction from the separator towards the current collector. Temporally, it was possible to track the transformation of Zn to ZnO during the discharge and follow the corresponding changes in the cathode.

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Simultaneous X-ray radioscopy/tomography and energy-dispersive diffraction applied to liquid aluminium alloy foams

Cited by 10 publications

References 18 publications

Using X-ray tomoscopy to explore the dynamics of foaming metal

Using X-ray tomoscopy to explore the dynamics of foaming metal

The Influence of Alloy Composition and Liquid Phase on Foaming of Al–Si–Mg Alloys

An operando spatially resolved study of alkaline battery discharge using a novel hyperspectral detector and X-ray tomography

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