Abstract
The microstructure evolution of medium manganese steel (Fe-5Mn-2Si-0.1C (wt%)) during thermo-mechanical processing in ferrite + austenite two-phase region was investigated by in situ neutron diffraction analysis and microstructure observations. When the specimens were isothermally held at a temperature of 700 °C, the fraction of reversely transformed austenite increased gradually with an increase in the isothermal holding time. However, it did not reach the equilibrium fraction of austenite even after isothermal holding for 10 ks. On the other hand, the fraction of reversely transformed austenite increased rapidly after the compressive deformation at a strain rate of 1 s−1 at 700 °C and reached the equilibrium state during subsequent isothermal holding for around 3 ks. Moreover, microstructure observations suggested that the austenite, which was reversely transformed during isothermal holding at 700 °C, exhibited film-like shape and existed between pre-existing martensite laths. In contrast, when the compressive deformation was applied during isothermal holding at 700 °C, most of the reversely transformed austenite had globular shapes with grain sizes less than 1 μm.
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References
Lee YK et al (2015) Current opinion in medium manganese steel. Mater Sci Technol 31(7):843–856
Arlazarov A et al (2012) Evolution of microstructure and mechanical properties of medium Mn steels during double annealing. Mater Sci Eng A 542:31–39
Cai ZH et al (2015) Austenite stability and deformation behavior in a cold-rolled transformation-induced plasticity steel with medium manganese content. Acta Mater 84:229–236
Han J et al (2014) The effects of the initial martensite microstructure on the microstructure and tensile properties of intercritically annealed Fe–9Mn–0.05C steel. Acta Mater 78:369–377
Hanamura T et al (2011) Excellent total mechanical-properties-balance of 5% Mn, 30000 MPa% steel. ISIJ Int 51(4):685–687
Shi J et al (2010) Enhanced work-hardening behavior and mechanical properties in ultrafine-grained steels with large-fractioned metastable austenite. Scripta Mater 63(8):815–818
Xu HF et al (2012) Heat treatment effects on the microstructure and mechanical properties of a medium manganese steel (0.2C-5Mn). Mater Sci Eng A 532:435–442
Hu J et al (2015) The determining role of reversed austenite in enhancing toughness of a novel ultra-low carbon medium manganese high strength steel. Scripta Mater 104:87–90
Zhao C et al (2014) Effect of annealing temperature and time on microstructure evolution of 0.2C-5Mn steel during intercritical annealing process. Mater Sci Technol 30(7):791–799
Huang H et al (1994) Retained austenite in low carbon, manganese steel after intercritical heat treatment. Mater Sci Technol 10:621–626
Zhao C et al (2014) Austenite thermal stabilization through the concentration of manganese and carbon in the 0.2C-5Mn steel. ISIJ Int 54(12):2875–2880
Acknowledgements
The neutron experiment at the Materials and Life Science Experimental Facility of the J-PARC was performed under a user program (Proposal No. 2016E0003, 2017E0001, 2017A0129). This study was financially supported by the Elements Strategy Initiative for Structural Materials (ESISM) through the Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan.
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Nakamura, Y. et al. (2018). In Situ Neutron Diffraction Study on Microstructure Evolution During Thermo-Mechanical Processing of Medium Manganese Steel. In: Stebner, A., Olson, G. (eds) Proceedings of the International Conference on Martensitic Transformations: Chicago. The Minerals, Metals & Materials Series. Springer, Cham. https://doi.org/10.1007/978-3-319-76968-4_24
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DOI: https://doi.org/10.1007/978-3-319-76968-4_24
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