Helena Van Swygenhoven-Moens, Paul Scherrer Institute and École Polytechnique Fédérale de Lausanne
Synchrotron Light to Investigate Materials In Operando

Synchrotron radiation beams are now sufficiently bright and detectors are sufficiently fast that scattering and x-ray absorption data can be followed in real time for a material under action. Imaging has been the most important use of x-rays since their discovery. With the use of synchrotron radiation, high-resolution computer-aided tomographic microscopy has become possible. One can now look at the formation of pores, micro-cracks or gas bubbles during the interaction of a material with an external environment. For crystalline solids it is clear that diffraction are important techniques to look insight a material. Scientists have developed dedicated devices for performing in situ experiments based on diffraction at synchrotron beamlines. For instance, it is now possible to study the evolution of a structure as it undergoes physical changes or chemical reactions, the transformation from one solid phase to another when a metallic alloy is heat-treated or put under mechanical stresses, or to provide information on the deformation mechanisms, corrosion and oxidation processes.

The in situ nature of the experiments enables an easier interpretation than traditional postmortem studies allowing pinning down the chronological sequence between events of a material in operando and providing accurate input for computational modeling.

This lecture will illustrate how synchrotron-based methods support materials science, covering a variety of materials including polymers, ceramics and metals, addressing manufacturing techniques such as laser-based near-net-shape methods as well as microstructural evolution during service conditions.

About Helena Van Swygenhoven-Moens

Helena Van Swygenhoven-Moens  is a professor at the École Polytechnique Fédérale de Lausanne (EPFL) in the Material Science Institute leading the Neutrons and X-rays for Mechanics of Materials laboratory and heads the Photons for Engineering and Manufacturing research group at the Paul Scherer Institute in Switzerland.          

Helena studied physics at the Free University of Brussels and received her PhD degree in physics from the Central Jury in Belgium. After a professional break for motherhood, she continued her career with a Marie-Heim Vögtlin grant from the Swiss National Science Foundation. Helena is a Fellow of the Materials Research Society, elected member to the Royal Academy of Science of Belgium, and an advanced grant holder from the European Research Council. For many years, she chaired the international board of the International Committee of Strength of Materials, was a member of the scientific advisory committee of European Spallation Source, was on the peer review panel of Diamond, and was on the beamline review panels of ESRF. Helena also serves on the engineering expert panel of the National Science Foundation Flanders and on expert panels of the European Research Council (ERC).

The core of her work is the development and use of in situ experiments at synchrotron and neutron facilities, with the aim to follow a material’s microstructure in operando and to provide synergies between experiments and computational modeling. Helena’s research focuses on the link between synthesis and microstructure, including laser-based additive manufacturing methods and the link between microstructure and mechanical behavior of a variety of materials ranging from nanostructured materials for watch components, super-elastic alloys for medical applications, and advanced steels and lightweight alloys for structural applications. Through her ERC advanced grant (MULTIAX), Helena addresses non-proportional multiaxial straining covering the gap between our current knowledge of mechanical behavior derived from uniaxial deformation tests and the engineering reality of applications and processing routes.