Prof. Dr. Helena Moens-Van Swygenhoven

Helena van Swygenhoven

Group Leader

Paul Scherrer Institute
Forschungsstrasse 111
5232 Villigen PSI
Switzerland


Biography

Helena Van Swygenhoven-Moens is Full Professor at the École Polytechnique Fédérale de Lausanne (EPFL) in the Material Science Institute leading the laboratory Neutrons and Xrays for Mechanics of Materials (NXMM). At PSI she heads the research group Photons for Engineering and Manufacturing (PEM).

She studied physics at the Free University of Brussels (VUB, Belgium) and received in 1983 her PhD degree in physics from the Central Jury in Belgium on radiation damage in crystalline and amorphous metals. After a professional break for motherhood, she started her career again with a Marie-Heim Vögtlin grant of the Swiss National Science Foundation in 1991 and joined the Fusion Technology Division at the Paul Scherrer Institute. She moved to the Neutron Spallation Source department in 1996 and was responsible for the Prompt Gamma Activation neutron beamline PGAA. Since 2005 she has been leading the group Material Science and Simulations (MSS) in the NUM department, which moved in 2015 to the PSD department and became the  PEM group.

She frequently advises private and public entities worldwide that are engaged in funding and evaluation of science and technology. Helena Van Swygenhoven chaired during many years the international board of ICSMA (International Committee of Strength of Materials). She served in several scientific advisory boards such as the European Spallation Source, the Doctoral Training Centre (DTC) of Imperial College, the computational Centre for Advanced Materials Modelling (ICAMS, Ruhr University Germany), the board “Information” of the Karlsruhe Institute of Technology and the ERC starting grant review panel. She is a fellow of the American MRS society and has been elected to the Belgian National Academy of Science. She is an ERC advanced grant holder.

Institutional Responsibilities

Helena Van Swygenhoven is responsible for the experimental and computational research program of PEM, and guides several PhD students and postdocs. She has directed numerous PhD research theses, all her students are enrolled in the doctoral Program Materials Science and Engineering (EDMX) of EPFL. She is also responsible for obtaining the necessary external finances for developing the research programs, requiring support from funding agencies or through direct collaboration with industry.

Scientific Research

The core of her work is the development and use of insitu and operando experiments at synchrotron and neutron facilities with the aim to follow a material’s microstructure during operation. Such experiments provide synergies between experiments and computational modelling, and therefore several of her research programs include computational simulations such as molecular dynamics, crystal plasticity and finite element based models.

Her research focusses 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, superelastic alloys for medical applications to advanced steels and lightweight alloys for structural applications. With her ERC advanced grant MULTIAX she addressed non-proportional multiaxial straining covering the gap between our current knowledge on mechanical behavior derived from uniaxial deformation tests and the engineering reality of applications and processing routes. Within MULTIAX several biaxial devices have been developed that can be installed in a synchrotron or neutron beamline as well as in a scanning electron microscope for HRDIC. Within the Strategic Focus Area research programs, an operando miniaturized SLM device has been developed for usage at SLS beamlines. All devices are available for external users.

Selected Publications

For an extensive overview we kindly refer you to our publication repository DORA.

Operando X-ray diffraction during laser 3D printing, Hocine S, Van Swygenhoven H, Van Petegem S, Chang C, Maimaitiyili T, Tinti G, Ferreira Sanchez D, Grolimund D, Casati N, Materials Today, 2019, 34, 30, DOI: 10.1016/j.mattod.2019.10.001
Ultra-fast operando X-ray diffraction experiments reveal the temporal evolution of low and high temperature phases and the formation of residual stresses during laser 3D printing of a Ti-6Al-4V alloy. The profound influence of the length of the laser-scanning vector on the evolving microstructure is revealed and elucidated.

Deformation and degradation of superelastic NiTi under multiaxial loading, Hsu W-N, Polatidis E, Šmíd M, Van Petegem S, Casati N, Van Swygenhoven H, Acta Materialia. 2019; 167, 149, DOI: 10.1016/j.actamat.2019.01.047
The degradation of the superelastic properties of a commercial NiTi alloy is studied during uniaxial, biaxial and load-path-change cycling performed in-situ with synchrotron X-ray diffraction. Degradation is found to depend strongly on the loading and unloading path followed. Cycling biaxially leads to faster degradation than uniaxially due to a larger accumulation of dislocations. If the deformation cycle contains a load path change, dislocation accumulation increases further and more martensite is retained.

In situ characterization of a high work hardening Ti-6Al-4V prepared by electron beam melting, Sofinowski K, Šmíd M, Kuběna I, Vivès S, Casati N, Godet S, Van Swygenhoven H., Acta Materialia, 2019, 179, 224. DOI: 10.1016/j.actamat.2019.08.037
In situ x-ray diffraction and high resolution digital image correlation are used to examine the strain partitioning between the phases in a multi-phase Ti–6Al–4V prepared by electron beam melting during tensile loading. It is shown that the work hardening is the result of composite load-sharing behavior between three mechanically distinct microstructures: large α lamellae and a martensitic region of fine acicular α' and a third phase not previously reported in this alloy.

Microstructure evolution of stainless steel subjected to biaxial load path changes: in-situ neutron diffraction and multi-scale modeling, Upadhyay MV, Capek J, Panzner T, Van Swygenhoven H, International Journal of Plasticity, 2019, 122, 49. DOI: 10.1016/j.ijplas.2019.06.006
The lattice strain and intensity evolution obtained from in-situ neutron diffraction experiments of 316L cruciform samples subjected to 45° and 90° load path changes are presented and predicted using a multi-scale modeling approach that we developed.
At the macroscale, the multi-scale approach uses the implementation of the viscoplastic self-consistent polycrystalline model as a user-material into ABAQUS finite element framework to predict the non-linearly coupled gauge stresses of the cruciform geometry. The predicted gauge stresses are then used to drive the elasto-viscoplastic fast Fourier transform polycrystalline model to predict the lattice strain and intensity evolutions. Both models use the same dislocation density based hardening law suitable for load path changes. The predicted lattice strain and intensity evolutions match well with the experimental measurements performed during insitu neutron diffraction.

Books

N/A