Song, Sang Yoon Jang, Tae Jin Lee, Chang-Gi Yang, Dae Cheol Sung, Min Young Lee, Gunjick Han, Jung Hun Baek, Ju-Hyun Suh, Jin-Yoo Zargaran, Alireza Saksena, Aparna Gault, Baptiste Ko, Won-Seok Kim, Se-Ho Sohn, Seok Su 2026-02-19T05:00:12Z 2026-02-19T05:00:12Z 2026-02-19 2026-04 1359-6454 https://pubs.kist.re.kr/handle/201004/154283 Achieving ultrahigh strength in advanced structural materials without compromising their resistance to hydrogen embrittlement (HE) remains a critical challenge. Here, we introduce a design strategy that exploits discontinuous L12 precipitation of strengthening particles also boosting HE resistance in a high-entropy alloy. The discontinuous reaction first produces serrated grain boundaries that induce crack deflection at multiple scales, effectively arresting intergranular crack propagation. The precipitates are ordered, coherent L12 nanorods with a high hydrogen trapping capability, as revealed by direct isotopically-labelled atom probe measurements and density functional theory calculations, significantly inhibiting hydrogen diffusion. This unique microstructural combination underpins a tensile strength of ∼1.7 GPa with a 33% superior HE resistance compared to a single-phase face-centered cubic reference alloy. Our strategy not only breaks the conventional trade-off between strength and HE, but also delivers higher gains in both tensile strength and HE resistance than conventional approaches, establishing discontinuous L12 precipitation as a versatile strategy for designing ultrahigh-strength HE-resistant alloys, with potential applications in hydrogen infrastructure and beyond. English Elsevier BV Reconciling ultrahigh strength and hydrogen embrittlement resistance via discontinuous L12 precipitation in a high-entropy alloy Article 10.1016/j.actamat.2026.121972 1 Acta Materialia, v.307 Acta Materialia 307 N scie scopus 001684829100001 2-s2.0-105029190562 Materials Science, Multidisciplinary Metallurgy & Metallurgical Engineering Materials Science Metallurgy & Metallurgical Engineering Article VACANCY FORMATION ENERGIES REDUCING GRAIN-BOUNDARY SOLUTE SEGREGATION DISLOCATION LINE TRAPPING SITES ATOMIC-SCALE CRACK-TIP DIFFUSION METALS FE Density functional theory calculation Hydrogen embrittlement Discontinuous L1 2 precipitation Cryo-atom probe tomography High-entropy alloy