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Antoine Casadebaigt defended his thesis on Oxidation behaviour of Ti-6Al-4V titanium alloy fabrication by Additive Manufacturing.

This picture was taken in July 2018

Thesis Subject

On the 3rd november 2020, Antoine Casadebaigt defended his thesis. His work was realized at CIRIMAT and IRT Saint Exupéry, under the supervision of Sciences de la Matière doctoral school.
The high quality and the relevance of Antoine‘s thesis contributed to get significant results as a part of AnDDurO project.

About this thesis

By combining additive manufacturing (AM) and titanium alloys, high mass and cost savings in aeronautic and space fields can be achieved. For these applications, titanium alloys can be used at high temperatures, up to 300-600°C depending on the alloy, and this can induce oxygen embrittlement. In this thesis, oxidation behaviour and influence of AM and oxidation on mechanical properties of Ti-6Al-4V titanium alloy fabricated by LBM and EBM were studied. Oxidations were performed from 400 to 600 °C and last between 25 and 10 000 h. Global oxidation kinetics, oxide layer growth rate and oxygen diffusion in the metal were characterized. Four characterizations methods of oxygen diffusion in the metal were compared. It was shown that oxidation of powder particles on the surface of as-built AM samples increases the mass gains. Nevertheless, high roughness of AM parts and HIP treatment, which one highly modified the alloy microstructure, do not influence oxide layer growth rate and diffusion of oxygen in the metal. Using thermogravimetric analysis allowed to obtain oxidation kinetics from 450 to 1 000 °C during a single experiment. With this method, it was shown that oxidation kinetics of LBM and EBM Ti-6Al-4V are close to conventionally processed Ti-6Al-4V and literature data. Higher mass gain of Ti-6Al-4V compared to Ti6242 comes from a thicker oxide layer whereas the oxygen diffusion zone is similar. This oxygen diffusion zone cracks during tensile tests, decreasing the ductility of 1.3 mm thick tensile specimens oxidized for 2000 h at 500 and 538 °C and 500 h at 600 °C. In the oxidation conditions studied, oxidation kinetics of LBM, EBM and conventionally processed Ti-6Al-4V are close to each other and oxidation influences only slightly tensile properties at room temperature.

AnDDurO Project

The AnDDurO project focuses on metal additive manufacturing technologies on powder bed fusion: Laser Beam Melting and Electron Beam Melting.This project provides to Members and Partners and capitalizes basic data on the physical, chemical, and mechanical properties of materials developed by additive manufacturing. This data is required for the design and sizing of structural elements.

A major effort will also be devoted to studying the durability and ageing of materials and structures in complex environments. The aim is to quantify the harmfulness of manufacturing defects. The control aspect of the process will be addressed by the implementation of control and processing means of the generated data, which should allow the detection of defects during the manufacturing process.

 

Three alloys will be studied: Ti64 (titanium base), 718 (nickel base), AS7G06 (aluminum base).

Jury

Daniel MONCEAU Thesis Director Research director / CNRS
Jonathan HUGUES Thesis Co-Director Research Engineer Additive Manufacturing / IRT Saint Exupéry
Florence PETTINARI-STURMEL President Professor / Université Toulouse 3
Sébastien CHEVALIER Rapporter Professor / Université de Bourgogne
Jérôme CREPIN Rapporter Research director / MinesParisTech
Sandy BLANC Examinator Engineer R&D / Safran Additive Manufacturing
Yannick CADORET Examinator Expert / Airbus France
Eric HUG Examinator Professor / Université de Caen

Related Publications

  • Communications
    • JECH 2018 (Journée d’étude sur la cinétique hétérogène), Dijon : présentation
    • Matériaux 2018, Strasbourg : présentation
    • Titanium 2019, Nantes : présentation
    • Gordon Research Conference – High temperature corrosion, San Diego, 2019 : présentation
    • HTCPM 2020 – High temperature Corrosion and Protection of Metarials, 2019 : présentation
  • Publications :
    • Casadebaigt, A., Hugues, J. & Monceau, D. Influence of Microstructure and Surface Roughness on Oxidation Kinetics at 500–600 °C of Ti–6Al–4V Alloy Fabricated by Additive Manufacturing. Oxid Met 90, 633–648 (2018). https://doi.org/10.1007/s11085-018-9859-0
    • Casadebaigt, J. Hugues, D. Monceau, High temperature oxidation and embrittlement at 500–600 °C of Ti-6Al-4V alloy fabricated by laser and electron beam melting, Corros. Sci. (2020), p. 108875, 10.1016/j.corsci.2020.108875