https://doi.org/10.1140/epjs/s11734-026-02174-5
Regular Article
High-temperature deformation and creep performance of a novel nitrogen-enhanced duplex stainless steel: systematic grain-size effects and implications for petrochemical applications
Department of Physics, National Defence Academy, Khadakwasla, 411 023, Pune, Maharashtra, India
a
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Received:
25
October
2025
Accepted:
27
January
2026
Published online:
26
February
2026
Abstract
Duplex stainless steels (DSS) are valued for their balance of strength and corrosion resistance, yet their high-temperature reliability remains constrained by limited creep data and unclear grain-size effects, particularly in nitrogen-alloyed variants. This study investigates a novel DSS composition (Fe–24Cr–6Ni–3Mo–0.27N bal.) with balanced austenite (51.79%) and ferrite (44.8%) phases, systematically varying grain sizes from 10 to 100 μm and testing deformation and creep behavior up to 1400 °C. Flow stress curves reveal temperature-dependent softening, with fine grains enhancing proof stress by 20–30% at 1000 °C, while coarse grains promote superplasticity at 1400 °C, reducing forging loads by nearly 50%. Creep rupture tests at 720 °C establish a safe operating window below ~ 350 MPa, where rupture lives exceed 105 h, ~ 25% longer than commercial 2205 DSS, confirming nitrogen’s role in retarding dislocation climb. Activation energies of ~ 375 kJ/mol for deformation and ~ 450 kJ/mol for creep highlight solute-drag-controlled climb as the governing mechanism. The novelty of this work lies in the first systematic quantification of grain-size effects on high-temperature proof stress, strain-rate sensitivity, and creep rupture in nitrogen-enhanced DSS, bridging a critical gap in the literature. These findings demonstrate that microstructural optimization enables both strength at moderate service temperatures and ductility at extreme processing conditions, positioning this alloy as a promising candidate for petrochemical reformers and heat exchangers operating at 700–800 °C with reliable long-term performance.
Supplementary Information The online version contains supplementary material available at https://doi.org/10.1140/epjs/s11734-026-02174-5.
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© The Author(s), under exclusive licence to EDP Sciences, Springer-Verlag GmbH Germany, part of Springer Nature 2026
Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
