Berlin 2024 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 19: Topical Session: Hydrogen in Materials: from Storage to Embrittlement II
MM 19.1: Topical Talk
Dienstag, 19. März 2024, 10:15–10:45, C 130
Hydrogen-Induced Fracture Behavior in Cr-Mo Low Alloy Steel: In-situ ETEM Insights on Crack Propagation — •Lin Tian1, Masanobu Kubota2, Petros Sofronis2,3, Reiner Kirchheim1,2,4, and Cynthia A. Volkert1,2,5 — 1Institute of Materials Physics, University of Göttingen, Göttingen, Germany — 2International Institute for Carbon Neutral Energy Research, Kyushu University, Fukuoka Japan — 3Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, USA — 4Max-Planck-Institute for Iron Research, Duesseldorf, Germany — 5The International Center for Advanced Studies of Energy Conversion (ICASEC), University of Göttingen, Göttingen, Germany
Taking advantage of an in-situ fracture test method inside an environmental transmission electron microscope (ETEM), the fracture behavior of a Cr-Mo low alloy steel is examined. Through controlled gas environments, we compared the fracture behavior of samples in vacuum and in hydrogen gas. In vacuum, the sample fractures by void nucleation and coalescence showing typical ductile fracture behavior. It is found that the ferrite matrix is the major void initiation site due to the low stress triaxiality in the thin sample. However, in the presence of hydrogen gas in the TEM chamber, clear evidence of hydrogen embrittlement is observed. The crack tip in hydrogen gas remains sharp and propagates by the formation and linking up of staircase-shape micro-cracks, without much associated plasticity. We will discuss possible contributions to embrittlement from the effect of hydrogen on (i) dislocation formation and mobility, and (ii) lattice decohesion.
Keywords: Hydrogen embrittlement; Steel; Dislocations; Environmental Transmission Electron Microscopy