Influence of Mn on nanobainite formation kinetics and austenite retention in Al-added medium-Mn steels subjected to hybrid isothermal annealing
This study investigates the bainite transformation kinetics, microstructural evolution, and mechanical properties of Al-alloyed 3MnNb and 4MnNb multiphase steels subjected to a novel hybrid heat treatment. Dilatometric analysis revealed that bainite formation in the 3MnNb steel initiates more rapidl...
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Elsevier
2025-07-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785425014127 |
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| author | Mateusz Morawiec Jarosław Opara Adam Skowronek Alireza Kalhor Aleksandra Kozłowska Anna Wojtacha Adam Grajcar |
| author_facet | Mateusz Morawiec Jarosław Opara Adam Skowronek Alireza Kalhor Aleksandra Kozłowska Anna Wojtacha Adam Grajcar |
| author_sort | Mateusz Morawiec |
| collection | DOAJ |
| description | This study investigates the bainite transformation kinetics, microstructural evolution, and mechanical properties of Al-alloyed 3MnNb and 4MnNb multiphase steels subjected to a novel hybrid heat treatment. Dilatometric analysis revealed that bainite formation in the 3MnNb steel initiates more rapidly during isothermal holding, while the 4MnNb steel exhibits accelerated transformation kinetics in later stages, resulting in distinct final bainite fractions. Thermodynamic calculations, including T0 curves, underscore the roles of Mn and Al in modifying the Gibbs free energy landscape and influencing the potential for nanobainite formation. Microstructural characterization identified a lath-type ferritic matrix comprising bainite, retained austenite (RA), and, in some cases, fresh martensite. Lower intercritical annealing temperatures (IATs) favored the formation of coarse ferrite laths and residual martensite, whereas higher IATs promoted microstructural refinement. Although 3MnNb achieved 10–15 % nanobainite, further transformation was limited by the stability of RA and sluggish carbon diffusion at 200 °C. In contrast, the 4MnNb steel displayed enhanced grain refinement, increased hardness, and a higher fraction of stabilized RA, which impeded the progression of nanobainite formation. |
| format | Article |
| id | doaj-art-82da2e5da5c241a6bcf2865a8dfa77af |
| institution | OA Journals |
| issn | 2238-7854 |
| language | English |
| publishDate | 2025-07-01 |
| publisher | Elsevier |
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| series | Journal of Materials Research and Technology |
| spelling | doaj-art-82da2e5da5c241a6bcf2865a8dfa77af2025-08-20T02:09:07ZengElsevierJournal of Materials Research and Technology2238-78542025-07-013754956210.1016/j.jmrt.2025.05.256Influence of Mn on nanobainite formation kinetics and austenite retention in Al-added medium-Mn steels subjected to hybrid isothermal annealingMateusz Morawiec0Jarosław Opara1Adam Skowronek2Alireza Kalhor3Aleksandra Kozłowska4Anna Wojtacha5Adam Grajcar6Silesian University of Technology, Faculty of Mechanical Engineering, Materials Research Laboratory, Konarskiego 18a St., Gliwice, 44-100, Poland; Corresponding author.Łukasiewicz Research Network–Upper Silesian Institute of Technology, 12-14 K. Miarki Street, Gliwice, 44-100, PolandSilesian University of Technology, Faculty of Mechanical Engineering, Materials Research Laboratory, Konarskiego 18a St., Gliwice, 44-100, PolandSilesian University of Technology, Faculty of Materials Engineering, Krasińskiego 8, Katowice, 40-019, PolandSilesian University of Technology, Faculty of Mechanical Engineering, Department of Engineering Materials and Biomaterials, Konarskiego 18a St., Gliwice, 44-100, PolandSilesian University of Technology, Faculty of Mechanical Engineering, Department of Engineering Materials and Biomaterials, Konarskiego 18a St., Gliwice, 44-100, PolandSilesian University of Technology, Faculty of Mechanical Engineering, Department of Engineering Materials and Biomaterials, Konarskiego 18a St., Gliwice, 44-100, PolandThis study investigates the bainite transformation kinetics, microstructural evolution, and mechanical properties of Al-alloyed 3MnNb and 4MnNb multiphase steels subjected to a novel hybrid heat treatment. Dilatometric analysis revealed that bainite formation in the 3MnNb steel initiates more rapidly during isothermal holding, while the 4MnNb steel exhibits accelerated transformation kinetics in later stages, resulting in distinct final bainite fractions. Thermodynamic calculations, including T0 curves, underscore the roles of Mn and Al in modifying the Gibbs free energy landscape and influencing the potential for nanobainite formation. Microstructural characterization identified a lath-type ferritic matrix comprising bainite, retained austenite (RA), and, in some cases, fresh martensite. Lower intercritical annealing temperatures (IATs) favored the formation of coarse ferrite laths and residual martensite, whereas higher IATs promoted microstructural refinement. Although 3MnNb achieved 10–15 % nanobainite, further transformation was limited by the stability of RA and sluggish carbon diffusion at 200 °C. In contrast, the 4MnNb steel displayed enhanced grain refinement, increased hardness, and a higher fraction of stabilized RA, which impeded the progression of nanobainite formation.http://www.sciencedirect.com/science/article/pii/S2238785425014127Advanced high-strength steelMedium-Mn steelNanobainitic steelRetained austeniteIntercritical annealingAustempering |
| spellingShingle | Mateusz Morawiec Jarosław Opara Adam Skowronek Alireza Kalhor Aleksandra Kozłowska Anna Wojtacha Adam Grajcar Influence of Mn on nanobainite formation kinetics and austenite retention in Al-added medium-Mn steels subjected to hybrid isothermal annealing Journal of Materials Research and Technology Advanced high-strength steel Medium-Mn steel Nanobainitic steel Retained austenite Intercritical annealing Austempering |
| title | Influence of Mn on nanobainite formation kinetics and austenite retention in Al-added medium-Mn steels subjected to hybrid isothermal annealing |
| title_full | Influence of Mn on nanobainite formation kinetics and austenite retention in Al-added medium-Mn steels subjected to hybrid isothermal annealing |
| title_fullStr | Influence of Mn on nanobainite formation kinetics and austenite retention in Al-added medium-Mn steels subjected to hybrid isothermal annealing |
| title_full_unstemmed | Influence of Mn on nanobainite formation kinetics and austenite retention in Al-added medium-Mn steels subjected to hybrid isothermal annealing |
| title_short | Influence of Mn on nanobainite formation kinetics and austenite retention in Al-added medium-Mn steels subjected to hybrid isothermal annealing |
| title_sort | influence of mn on nanobainite formation kinetics and austenite retention in al added medium mn steels subjected to hybrid isothermal annealing |
| topic | Advanced high-strength steel Medium-Mn steel Nanobainitic steel Retained austenite Intercritical annealing Austempering |
| url | http://www.sciencedirect.com/science/article/pii/S2238785425014127 |
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