Experimental Study of Hydrogen/crystalline Defect

**Experimental study of hydrogen/crystalline defect interactions in martensitic steels and impact on the embrittlement mechanisms**:

- Réf **ABG-124088**
- Sujet de Thèse- 23/05/2024- Contrat doctoral- Groupe de Physique des Matériaux- Lieu de travail- Rouen - Normandie - France- Intitulé du sujet- Experimental study of hydrogen/crystalline defect interactions in martensitic steels and impact on the embrittlement mechanisms- Champs scientifiques- Matériaux
- Energie
- Physique
- Mots clés- Martensitic steels, Hydrogen, Crystalline defects, Segregation, Electron microscopy, Atome probe tomography, Structure/property relationships**Description du sujet**:
**Context**

Metallic alloys are essential materials at all levels for the production, storage or transport of hydrogen. The aim of this project is to deepen fundamental knowledge of the interactions at atomic scales between hydrogen and crystalline defects or carbides in steels. This is an important issue, since it is linked to hydrogen embrittlement, a phenomenon with major industrial consequences. Several phenomenological models already exist which are based on hypothesis related to these hydrogen/defect interactions. There is however a lack of knowledge especially in complex or dynamic configurations when other solutes are present (such as carbon in solid solution) or when dislocations interact with carbides that have potentially trapped H atoms.

**Objectives**

In this PhD project, we propose an original approach based on model microstructures obtained by heat treatment of steels to obtain different configurations (martensite, tempered martensite, ferrite with nanoscaled carbides). These materials will be electrolytically charged with hydrogen, and the trapping sites identified by TDS and atom probe tomography. Particular attention will be paid to the competition between carbon and hydrogen atoms for segregation on dislocations and grain boundaries. This information will be correlated with simulation undertaken by the other partners of the “Hystyle ANR Project”. To study dynamic effects, microstructures will be aged in-situ by transmission electron microscopy under hydrogen atmosphere. Finally, correlation with embrittlement mechanisms will be undertaken via micromechanical tests (in-situ compression or bending of micro-samples) enabling individual structural entities (grain boundaries, for example).

**Prise de fonction**:

- 16/09/2024**Nature du financement**:

- Contrat doctoral**Précisions sur le financement**:

- Fiancement acquis - sur un projet PRC ANR**Présentation établissement et labo d'accueil**:

- Groupe de Physique des MatériauxLes activités scientifiques du GPM trouvent leurs racines dans l’histoire du laboratoire dont les prémices remontent à la fin des années 60. L’instrumentation scientifique y a toujours joué un rôle central, et les techniques de microscopie et d’analyse des matériaux un rôle fédérateur. Des évolutions progressives ont forgé le GPM d’aujourd’hui, qui possède une plateforme instrumentale de premier rang mondial et des activités dans de nombreux champs thématiques. Celles-ci sont distribuées dans cinq départements thématiques : Instrumentation Scientifique / Métallurgie, Microstructures, Mécanique / Matériaux Fonctionnels et nanostructures / Systèmes désordonnés et Polymères / Ouvertures thématiques et Innovation

**Site web**:
**Intitulé du doctorat**:

- Physique des Matériaux**Pays d'obtention du doctorat**:

- France**Etablissement délivrant le doctorat**:

- UNIVERSITE DE ROUEN**Ecole doctorale**:

- Physique, Sciences de l'Ingénieur, Matériaux, Energie (PSIME)Engineering degree and/or a Master degree. Strong motivation for experimental research on advanced techniques. Excellent background in materials science and physical metallurgy (phase transformations, crystalline defects and relationships between microstructures and mechanical properties). Prior experience in the field of microstructural characterization, mechanical properties and study of structure/properties relationships in a metallic alloys would be highly appreciated. Good written and oral communication skills, and fluency in English.- 06/07/2024