The TTcH platform at the MSMP laboratory on the Aix-en-Provence campus is celebrating its 10th anniversary!

An exact reproduction of an industrial process, it served as a reference for the Nit++ project (Guillaume Fallot's CIFRE thesis defended in 2015), in partnership with Eurocopter (now Airbus Helicopters).

This platform stands out in particular thanks to its Setaram Setsys EVO 16/18 thermobalance, which allows heat treatments of up to 1400°C in a reactive atmosphere (NH3, H2, O2, CO, CO2) while monitoring changes in the mass of the samples treated with a sensitivity of 30 nanograms (equivalent to around 30 cells).

This co-financing, amounting to €150k for equipment and the same amount for infrastructure (room, gas system and equipment, safety, etc.), shared between Arts et Métiers Airbus Helicopters, has enabled, among other things, the development of the "deep" industrial nitriding range for the new generation of helicopter power transmissions produced in Marignane.

Steel nitriding, a subject that has been central to the laboratory's work for 30 years

Historically, the nitriding of steels has been a key topic in the research area of "Microstructure/property/process relationships" in materials with property gradients, which has been pursued by the MSMP laboratory for over 30 years!

Prof. Laurent BARRALLIER, director of the MMS team at the MSMP laboratory, supervised the first thesis in 1992 on the genesis of residual stresses in nitrided layers of structural steels in partnership with Airbus Helicopters. This was followed by the development of these activities through four theses:

• 1998, CIFRE thesis by Jean-Noël LOCQUET on the characterization of the microstructure of nitrided layers, in partnership with Airbus Helicopters;
• 2000, thesis by Michel CHAUSSUMIER on the modeling of multiaxial fatigue in nitrided steel parts;
• 2006, Vincent GORET's CIFRE thesis on modeling the nitriding treatment of construction steels with complex geometries, in partnership with Airbus Helicopters;
• 2009, CIFRE thesis by Sébastien JÉGOU on the role of alloying elements and carbon in the formation of residual stresses in nitrided steels, in partnership with Aubert & Duval and Safran.

Industrial partnerships
 

Since 2011, the MSMP laboratory has strengthened its position (recruiting Sébastien JÉGOU as Associate Professor) and developed its R&D partnerships in the field of gas nitriding treatment of structural steels through five theses:

• 2015, Guillaume FALLOT's CIFRE thesis on the optimization of deep gas nitriding of structural steels, in partnership with Airbus Helicopters;
• 2016, Benjamin GUILLOT's FUI thesis on pre-nitriding surface preparations for structural steels, in partnership with Airbus Helicopters, Bodycote, Renault Sport F1 (now Alpine), and Transvalor;
• 2017, Hadrien WEIL's CIFRE thesis on modeling the functional requirements of nitrided structural steels (fatigue resistance) in partnership with Safran Transmission Systems;
• 2018, CIFRE thesis by François GODET on the relationship between the microstructures of nitrided layers and the optimization of fatigue properties in treated surfaces, in partnership with IRT M2P, Safran Tech, NTN-SNR, Airbus Helicopters, and Naval Group;
• 2022, Lisa GERMAIN's APCD thesis on the relationship between interstitial diffusion phenomena and deformation and stress gradients applied to the nitriding of steels.

And today

With over 30 years of knowledge and expertise, the MSMP laboratory now applies its cross-disciplinary R&D approaches to new grades of steel (tool steel, electrical steel, hybrid steel, etc.) and to modeling for Industry 4.0 thermochemical surface treatments, thanks to three theses:

• 2023, CIFRE thesis by Yanxue ZHANG on optimizing nitriding conditions for tool steels, in partnership with Lisi Automotive;
• 2024, AMVALOR thesis by Flavien DELARBRE on optimizing the kinetics of oxidation/decarburization and nitriding of electrical steels, in partnership with thyssenkrupp Electrical Steel;
• 2025, CIFRE thesis by Patricia RAZAFIMAHEFA on 4.0 modeling of gas nitriding treatment for structural steels, in partnership with IRT M2P and Safran Transmission Systems.

Research related to teaching

The past 10 years have also been an opportunity to consolidate academic partnerships with manufacturers through numerous end-of-study internships and expertise projects (e.g., validation of TRL5 and 6 for the new range of construction steel nitriding from Safran Transmission Systems).

The year 2023 will mark the launch of two end-of-studies internships in collaboration with Safran Transmission Systems. Their objective will be to continue developing the TTcH platform's activities with research into new generations of more environmentally responsible DUPLEX surface treatments. They will be the starting point for a new three-year collaborative project between the MSMP laboratory and Safran Transmission Systems focusing on thermochemical surface treatments.

Teaching is not left behind, with a pedagogical approach based on these examples of R&D applications, but also on the technical resources of this platform, particularly through teaching units (MATA = Advanced Materials and COPA-REPA = Designing and Manufacturing Advanced Products) and second-year projects (PJT). This teaching approach is also developing in line with the rise of Industry 4.0 in order to offer solutions for predicting properties suited to this type of processing.

The TTcH platform team: Prof. Laurent BARRALLIER (University Professor), Dr. Sébastien JÉGOU (Senior Lecturer), Dr. Fabrice GUITTONNEAU (Research Engineer), Jean-François MATHIEU (Design Engineer), and Jean-Philippe MARTIN (Technician).

Pfeiffer Vacuum OMNIstar GSD 320 mass spectrometer, and (right) Setaram Setsys EVO 16/18 thermobalance