Researchers/Teaching researchers
David Tingaud (resp.)
Guy Dirras
Jia Li
Dominique Vrel

Students/Post-docs
Juliette Gandolfi
Mohamed Amine Hattal
Dame Assane Kane
Adrien Mourgout

Background and scientific challenge: The design of metal alloys combining increased mechanical strength and ductility is the holy grail of traditional metallurgy. Powder metallurgy is a versatile solution that makes it possible to combine these two opposing properties. The structure consists of a perfectly controlled mixture of Ni powder and nano W sintered by SPS.

Results obtained: Optimum composition achieved, combining mechanical strength and ductility. The brittleness of the W phase is offset by the ductility of the Ni(W) solid solution.

Scientific area and applications: Structural materials (transport, etc.), hard coatings, etc

Publications : T. Sadat et al, Materials & Design. Doi: https://doi.org/10.1016/j.matdes.2015.10.083

(C) EBSD mapping of grain size distribution for TA6V with “harmonic” structure

Background and scientific challenge: The design of metal alloys combining increased mechanical strength and ductility is the holy grail of traditional metallurgy. The concept of “harmonic structure” enables these two antagonistic properties to coexist. The structure consists of an ultra-fine-grained skeleton surrounding a coarse-grained core and is applicable to a wide range of materials.

Results: high mechanical strength with no loss of tensile ductility compared with a conventional microstructure. Modification of plasticity mechanisms (Inhibition of adiabatic shear bands in high-speed direct impact in Ti [1,2]; Inhibition of mechanical maclage in Ti-Nb-Zr [3] in QS stresses. Collaboration is underway with the CMA – Conception de matériaux architecturés research operation on this theme with a view to numerically simulating the mechanical behaviour of this type of alloy.

Scientific area and applications: Structural materials; aeronautical and biomedical applications

Academic and industrial partners: Ritsumeikan University, Japan, CEMES, Pprime, IJL, Nexter

Publications : [1] Dirras et al, Matériaux & Techniques, 103(3), 311. doi : doi:10.1051/mattech/2015031; [2] Ameyama et al, Materials Letters, 2022. doi: https://doi.org/10.1080/21663831.2022.2057203; [3] Dirras et al. Scripta Materialia 138 (2017) 44-47 https://doi.org/10.1016/j.scriptamat.2017.05.033.

Context and scientific challenge: As the population of modern societies ages and the risk of bone diseases or accidents has increased, the need for a new generation of materials with superior biocompatibility and adequate mechanical properties is a challenge. Two innovative metallurgical concepts (additive manufacturing and high-entropy alloys) need to be mastered to meet this essential public health challenge.

Results obtained: Various optimised and optimisable compositions. Young’s modulus 50% lower than Ti-6Al-4V. Mechanical strength of the order of GPa (maximum stress in compression: around 2 GPa)

Scientific field and application: Structural materials (biomedical, defence)

Academic and industrial partners: Thiot Ingénierie; Nexter Munitions; Z3DLab; ICMPE

Publications: in progress (A. Mourgout thesis, J. Gandolfi thesis)