Jeong, Chang-Gon Trang, T. T. T. Kim, Yeon-Seok Jun, Hyun Jo Jin, Hyun-Woo Suh, Jin-Yoo Heo, Yoon-Uk 2026-05-11T10:00:06Z 2026-05-11T10:00:06Z 2026-05-07 2026-05 0921-5093 https://pubs.kist.re.kr/handle/201004/154748 High-Mn steels (HMSs) exhibit excellent mechanical properties, yet their relatively low yield strength (YS) and susceptibility to hydrogen embrittlement (HE) remain critical limitations for structural applications. To address these challenges, grain refinement and precipitation hardening are promising approaches, as they enhance YS and introduce immobile hydrogen trapping sites. In this study, we elucidate the relationship between HE behavior and multiple strengthening mechanisms in micro-alloyed HMS by systematically varying the annealing temperature after cold rolling. Controlled microstructures with varying grain size and precipitate fraction successfully improved YS without loss of ductility under hydrogen-free conditions. However, after hydrogen charging, the susceptibility to HE increased significantly with lower annealing temperatures. High-resolution transmission electron microscope (HR-TEM) and geometric phase analysis (GPA) revealed that annealing conditions influenced hydrogen migration into strain-concentrated regions, leading to different crack initiation sites such as γ-austenite/ε-martensite and mechanical twin/matrix interfaces. These differences originated from variations in γ-austenite phase stability caused by carbide precipitation and hydrogen charging. Furthermore, the higher YS confined the plastic zone in front of the crack, accelerating hydrogen concentration and crack propagation in the plastic zone. Overall, the results show that HE susceptibility in HMSs is governed not only by matrix composition but also by matrix strength, providing important insights for designing high-strength, HE-resistant HMSs. English Elsevier BV Microstructure-strength interplay governing hydrogen embrittlement in micro-alloyed high-Mn steels Article 10.1016/j.msea.2026.150055 1 Materials Science and Engineering: A, v.960 Materials Science and Engineering: A 960 N scie scopus 001727506500001 2-s2.0-105032820504 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Metallurgy & Metallurgical Engineering Science & Technology - Other Topics Materials Science Metallurgy & Metallurgical Engineering Article STACKING-FAULT ENERGY INDUCED PLASTICITY STEELS EPSILON-MARTENSITE DELAYED FRACTURE FLOW-STRESS GRAIN-SIZE TENSILE FE TEMPERATURE MECHANISM High-Mn steels Hydrogen embrittlement Mechanical twinning Deformation-induced martensitic transformation