Sung, Min Young Jang, Tae Jin Lee, Hahun Lee, Gunjick Nam, Seungjin Park, Gyumin Zhang, Siyuan Kim, Se-Ho Sohn, Seok Su 2026-02-19T04:30:07Z 2026-02-19T04:30:07Z 2026-02-19 2026-03 0921-5093 https://pubs.kist.re.kr/handle/201004/154269 Achieving a favorable balance of strength and ductility at cryogenic temperatures requires concurrent control of yield strength and deformation mechanisms. Conventional carbide-based strengthening in Fe-based alloys can improve strength and modify deformation behavior, but often induces strain localization due to the non-shearable nature of carbides. Here, we show that nanoscale Cu precipitation in a designed Fe66Cr14Ni12Mn2Mo1Cu5 alloy simultaneously enhances strength and tailors stacking-fault energy (SFE) to activate multiple deformation modes. The coherent Cu precipitates with an average radius of ∼3 nm and a volume fraction of ∼5% contribute ∼190 MPa to yield strength through a shearing mechanism. The depletion of matrix Cu reduces the SFE from 23.3 mJ m−2 in the solutionized alloy to 15.6 mJ m−2, enabling deformation twinning at ambient temperature and promoting an earlier onset of γ→α′ martensitic transformation at 77 K. Consequently, the present alloy achieves a tensile strength of 1.43 GPa with ∼70% elongation at 77 K, corresponding to a strength–ductility product exceeding 10 GPa%. These findings establish precipitation engineering with shearable Cu precipitates as an effective strategy for simultaneously enhancing strength and controlling deformation pathways in cryogenic structural alloys. English Elsevier BV Strength–ductility synergy at ambient and cryogenic temperatures via Cu-precipitation-tuned stacking fault energy in a Fe–Cr–Ni–Mn–Mo–Cu alloy Article 10.1016/j.msea.2026.149862 1 Materials Science and Engineering: A, v.955 Materials Science and Engineering: A 955 N scie scopus 001685782500001 2-s2.0-105029020181 Nanoscience & Nanotechnology Materials Science, Multidisciplinary Metallurgy & Metallurgical Engineering Science & Technology - Other Topics Materials Science Metallurgy & Metallurgical Engineering Article TENSILE DEFORMATION-BEHAVIOR MECHANICAL-PROPERTIES GRAIN-SIZE MARTENSITIC-TRANSFORMATION MICROSTRUCTURE EVOLUTION IMPACT PROPERTIES STAINLESS-STEEL AUSTENITE CONTRAST COPPER Cu precipitation Stacking fault energy Deformation twinning Martensitic transformation Cryogenic mechanical properties