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IMMC

Olivier Hubert
PhD student
Ir. at UCL in 2014
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Main project: The influence of diffusible hydrogen on the mechanical behavior of third generation steels with a bainitic-martensitic matrix exhibiting a TRIP effect
Funding: FRIA
Supervisor(s): Pascal Jacques

In the automotive sector, the latest developments led to the era of third generation steels, exhibiting levels of strength up to 1200MPa, while keeping an adequate ductility. However, this new generation of steels is potentially sensitive to hydrogen embrittlement. Even though hydrogen embrittlement is studied for over 50 years now, it only starts to become an issue in the case of low alloy steels that start to reach problematic levels of strength.

The purpose of my research work is to investigate the role and the impact of the diffusible hydrogen on the mechanical behavior of third generation steels presenting a martensitic and/or bainitic matrix together with retained austenite exhibiting a Transformation-Induced Plasticity (TRIP) effect. In order to generate such microstructures, a heat treatment called "Quenching and Partitioning (Q&P)" is carried out in hydrogen-rich atmospheres. More specifically, the role of each phase on the hydrogen capture and/or diffusivity, as well as the influence of other microstructural parameters such as grain boundaries is studied.

Single phase martensitic and bainitic microstructures exhibiting different strength levels were processed. The influence of diffusible hydrogen in each microstructure is then studied either after cathodic hydrogen charging or in the case of gaseous hydrogen charging during the annealing process.

What's the influence of the microstructure on the hydrogen capture ?
How does the microstructure affect the notions of solubility and diffusivity of hydrogen ?
How does hydrogen affect the TRIP (TRansformation Induced Plasticity) effect ?

IMMC main research direction(s):
Processing and characterisation of materials

Keywords:
metallic alloys
metallurgy

Research group(s): IMAP
Collaborations: Cédric Georges (CRM Group), CRM Group, Arcelor Mittal

    

Recent publications

See complete list of publications

Dissertations


1. Hubert, Olivier. The influence of diffusible hydrogen on the tensile properties of model high strength steels, prom. : Jacques, Pascal, 30/01/2019. http://hdl.handle.net/2078.1/214126