Inhibition of grain growth by pearlite improves hydrogen embrittlement susceptibility of the ultra-low carbon ferritic steel: the influence of H-assisted crack initiation and propagation mechanisms

• DOI: 10.1007/s10853-023-08856-y
• Publication Date: 2023-08-29T15:03:18Z
• Authors: Stefanie Pichler; Artenis Bendo; Gregor Mori; Mahdieh Safyari; Masoud Moshtaghi
• Keywords: Embrittlement

Abstract The influence of grain growth inhibition by pearlite on hydrogen embrittlement (HE) behavior ultra-low carbon ferritic steels was studied. Fe-0.02C alloy has a considerable sensitivity to HE, while the Fe and Fe-0.1C materials have lower HE sensitivity. high fraction high-angle boundaries (HAGB) is responsible for shift peak higher temperature in alloy. trapping HAGBs observed mapping. Higher density contributes trap H diffusion coefficient. coexistence enhanced decohesion (HEDE) hydrogen-enhanced localized plasticity (HELP) mechanisms identified discussed. results indicate that HEDE active initial stage tensile loading during crack initiation HELP rest testing duration controls propagation. Due reduction size caused addition pearlite, normalized content per HAGB length significantly than Fe-0.1C, which means critical amount local required less likely accumulate due weakening cohesive interatomic strength. In alloy, ciritcal built up at HAGBs, resulting activation mechanism initiation. possibility accumulating concentration limited HEDE-based propagation events based mechanism.