SKM 2023 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 27: Hydrogen in Materials

MM 27.3: Talk

Wednesday, March 29, 2023, 10:45–11:00, SCH A 215

Role of diffusible hydrogen on the mechanical behavior of bcc alloys by in situ micromechanics during hydrogen charging — •Maria Jazmin Duarte Correa, Jing Rao, and Gerhard Dehm — Max-Planck-Institut für Eisenforschung, Düsseldorf, Germany

Hydrogen embrittlement represents a major challenge for the use of hydrogen (H) as energy carrier. Understanding individual hydrogen-microstructure interactions by targeting analyses at the nano-/microscale during H exposure is essential to prevent material degradation. We will present nanoindentation and micropillar compression tests during H charging of Fe-Cr alloys (8-20 wt.%Cr) using our novel "back-side" electrochemical H charging approach for nanoindentation related techniques. An enhanced dislocation nucleation is shown consistent with the defactant theory, and a hardening effect while increasing the Cr content and the H entry. The mechanical data is as well analyzed in terms of the diffusion behavior and used to develop a nanohardness-based H diffusion coefficient approach. On the other hand, our unique method allows differentiating between the effects of trapped and mobile H, and performing well controlled measurements with different H levels monitored over time to consider H absorption, diffusion and release through the metal which will be shown using the example of the model alloys mentioned above.