|May 18, 2022, 4:00 p.m. (CEST)
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Place: Pfaffenwaldring 7, V7.01
The vast majority of physical properties of both fabricated and natural materials are a manifest of their internal structure. The latter is usually directly influenced by transient phenomena occurring during formation or production. Likewise, a material's dynamic behaviour under changing conditions is intimately linked to its microstructure and its evolution as a function of time or externally applied conditions. A thorough understanding of these structural changes may thus allow for tailoring the performance of a material for specific purposes or the precise prediction of its failure modes. However, many dynamic processes, such as crack propagation in composites, bubble formation in metal foams, dendrite growth during solidification, particle rearrangements in granular materials, etc., occur within opaque materials usually hosted in complex conditioning environments on microscopic length scales and sub-second time scales, making them elusive to common characterization methods. To overcome these limitations, the latest developments in time-resolved synchrotron microtomography have pushed the routinely achievable time resolution well into the sub-second regime, reaching up to hundreds of tomographies per second for selected material systems, while allowing for ever more complex environments to produce realistic sample conditions. With the development of advanced tomographic reconstruction algorithms, even a live preview of virtual slices through 3D volumes in nearly real time is possible. Combining these advances in X-ray topographic imaging with cutting edge materials testing equipment, such as high-precision rheometers, or novel imaging modalities, like X-ray tensor tomography to reveal anisotropic microstructure orientation over large fields of view, opens up a vast landscape of new opportunities for materials science. I my talk, I will present a selection of recent research examples from the TOMCAT beamline at the Swiss Light source benefitting from these new developments, with use cases ranging from foaming dynamics in metal foams via fluid flow through porous media to rheological investigations of packed granular materials and orientation analysis of fibre suspensions under extensional flow.
Christian Matthias Schlepütz is a beamline scientist at the TOMCAT beamline for tomographic microscopy at the Swiss Light Source. He received his Ph.D. in experimental Physics from the University of Zürich in 2009 for his doctoral thesis on the topic of surface X-ray diffraction performed at the Materials Science Beamline of the Swiss Light Source. After a postdoctoral fellowship at the University of Michigan, Ann Arbor, he became a beamline scientist in 2011 at the Surface Scattering beamline, Sector 33, of Argonne National Laboratory’s Advanced Photon Source near Chicago. In 2015, he returned to Switzerland to join the TOMCAT team and since specializes in high-speed time-resolved tomographic measurements of dynamic systems.