Post-Doc In-situ characterization of hydrogen embrittlement of fretted surfaces

The expansion of gaseous hydrogen as an energy vector for transport and industry requires the development of robust pressurized components (tanks, valves, pumps). However, hydrogen is known to embrittle materials and hinder surface lubrication. While significant research has focused on toughness and fatigue, the field of tribology remains underdeveloped, particularly regarding industrial conditions involving high pressure and large contact areas.

The ANR-funded TrHy project aims to address these challenges by developing more representative experiments and models. This post-doctoral position aims to contribute to the project by characterizing the mechanical properties of fretted surfaces to refine the wear model. Fretting can induce plastic deformations that create a gradient of properties beneath the surface; under certain conditions, a fragile, white, nanocrystalline layer forms at the extreme surface. This surface embrittlement is further exacerbated by the well-known embrittling effect of hydrogen. Since surface wear depends directly on these mechanical properties, accurate characterization is essential for better predicting interface behavior.

To achieve this, nano-indentation and notched micro-cantilever tests, performed on samples machined by FIB, will be used to determine the mechanical properties and fracture toughness of the debris beds and the subsurface microstructure. The goal is to establish a local map of the mechanical properties of the fretted surface and, most innovatively, a map of hydrogen embrittlement beneath the fretted interface.

Profile sought:

PhD in mechanics of materials with experience experimental mechanics, especially in-situ micromechanical testing. Interest in test-calculation dialogue.

Supervisers :

Camille Gandiolle and Louis Cornet