Tomoscopy

time-resolved tomography

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Tomoscopy - fast operando tomography for materials science and engineering

Capturing X-ray tomographic views of objects used to consume a lot of time since samples have to be rotated around their axis, during which hundreds of radiographic projection images are collected. With the developments of the past years real-time 3D movies of solidifying microstructures, expanding metal foams and of materials during processing can be obtained, currently at the rate of more than 200 per second.

Starting in 2019, the German DFG is funding the further development of the tomoscopy technique and its applications with a "Reinhart Koselleck Project" at the TU Berlin.

Experimental setup:

Tomography experiment at TOMCAT beamline of the Paul-Scherrer-Institute. The crucible is rotating at 10 revolutions per second, yielding 20 tomograms per second (20 tps) as each tomogram requires a 180° rotation. Two 150 W infrared lamps allow for heating the crucible up to 700 °C.


Pore nucleation in metal foam:

Foaming process of AlMg17.5 alloy in an early stage. 5 Tomograms are obtained per second (5 tps) and the period of observation is 10 s. Spatial resolution is 3 µm. Bubbles have been segmented and colour-coded to follow them individually.


The power of image analysis:

Foaming of AlSi8Mg4 alloy containing 0.25 wt.% TiH2 observed for 40 s. Tomograms have been obtained at 1 tps. Spatial resolution is 3 µm. One individual Al50Mg50 particle in the sample has been extracted (grey). This particle melts first due to the low melting point of 450 °C, after which pores are formed within as shown in the tomography sequence.


Entire foaming process:

Foaming of AlSi8Mg4 alloy containing 0.25 TiH2 has been investigated in high time resolution. 20 Tomographies per second (20 tps) were acquired. A slice through the centre of the foam is shown. White spots are TiH2 blowing agent particles, pores are black. Total duration of experiment is 150 s, 80 s are shown.