The pooling of various skills has enabled this group to strengthen research subjects already recognized at international level and to open new subjects at the border between already existing subjects (hydrogen and additive manufacturing, for example). The scientific activities of this group have thus been grouped around 3 main axes which are: 1) Intermetallics and hydrides 2) Digital metallurgy and 3) Powder and composite metallurgy.
Digital metallurgy is reorganized around the coupling between physics-based modeling, data science and combinatorial experiments by additive manufacturing applied to functional and structural metallic materials. The intermetallic and hydride axis focuses on catalysis and the search for new superconductors. Finally, for the Powder and Composites Metallurgy axis, additive manufacturing of SLM and FDM type is established at the ICMCB in order to develop new processes for the synthesis of metals and composites with inorganic and organic matrix.
Scientific skills and interests
- Powder, Composites and Ceramics Metallurgy
The activity of this axis is centered around powder metallurgy (sintering), as a rational method of producing composite and ceramic materials with functional properties. This is a materials science type approach but with a desire to open up to other disciplines such as physics (thermal conductivity, radioelectric waves), while relying on the historical base of solid chemistry laboratory and existing skills in this area within the group.
On the one hand, we are interested in the study and modeling of sintering (de-densification phenomena, rapid sintering) for applications in the field of nuclear fuels and ceramics for optics. On the other hand, this path has been widely developed both from the point of view of understanding the phenomena of densification and chemical reactivity and for the development of composite materials with a metallic matrix and controlled microstructure (chemical evolutions in Cu/C, role of microstructure on the functional properties of composites).
These various works have given rise to the development of new research activities concerning the development of composite materials by additive manufacturing. This concerns both polymer matrix composites in which sintered inorganic fillers of given sizes and characteristics must be incorporated, as well as the printing of Cu/C type metal matrix composites, by additive manufacturing techniques of SLM type (Selective laser melting).
- Intermétalliques et hydrures
The activity of the “intermetallic and hydrides” axis is in line with a solid chemistry approach. It aims to synthesize new ternary and quaternary phases essentially containing a rare earth (RE), a transition metal and a p metal or magnesium. In addition, we are interested in the insertion, in these phases, of hydrogen but also of other light elements such as carbon, nitrogen or fluorine, for example. The activity around hydrogen is both fundamental and applicative. Indeed, we are studying the modification of physical properties (magnetic, Kondo effect, superconductivity) by hydrogenation, in close collaboration with theorists (DFT calculation), physicists from LOMA (multidisciplinary thesis) and physicists from Institut Néel (ANR project). We are also developing a new activity around the catalytic synthesis of ammonia.
In addition, the other targeted applications are the storage of hydrogen, the lightening of structural materials (phase rich in Mg) and the production of hydrogen by hydrolysis. While the first two applications are fairly standard, the last is much less standart. A prototype for the power supply of a bicycle was thus developed. More recently we are looking to develop a system for generating hydrogen under high pressure (a few hundred bars).
- Digital metallurgy
The activity of the “Digital metallurgy” axis is based on foundations specific to physical metallurgy. It is part of a better understanding of the process/microstructures/properties triptych. More specifically, it is about:
– control the phase transformation processes in the liquid and/or solid state in order to develop metallic materials with unusual structural and/or functional properties. To do this, we are interested in the influence of thermomechanical processes, rapid solidification but also those of additive manufacturing (SLM),
– better understand the link between microstructural parameters and structural properties such as weight reduction in the field of transport and/or functional properties such as energy storage and conversion,
– to develop innovative methods (i) of characterization of transformation interfaces by coupling the 3D tomographic atomic probe and EBSD) (ii) of high throughput characterization in the space of the compositions using the technique of 3D printing known as multi-jet fusion.
Our approach is supported by medium-field physical modeling approaches at the mesoscopic scale. The systems studied are very varied: iron bases, titanium bases, high entropy alloys but also hetero-composite materials based on polymer (s), ceramic (s) and metals.