Mechanism of Dynamic Strain-Induced Ferrite Transformation in a 3Mn-0.2C Medium Mn Steel
Received date: 2021-05-07
Revised date: 2021-06-30
Online published: 2021-07-20
Supported by
National Natural Science Foundation of China(52071322);National Natural Science Foundation of China(51771192);National Natural Science Foundation of China(U1708252)
Medium Mn steels (MMSs) have Mn contents of 3%-12% (mass fraction), and have been energetically investigated as the most promising candidates of the third-generation advanced high-strength steel. Their phase transformations and microstructures during various heat treatments and thermomechanical processes have received wide attention with the purpose to achieve an optimal balance of cost-efficient alloying compositions and mechanical properties. The aim of this work is to investigate the microstructural behavior of deformation-induced ferrite transformation (DIFT), starting from austenite, which occurs in MMS. Then, improved understandings of the formation of ultrafine ferrite via the DIFT and conservation of this microstructure during the post-deformation period can be obtained. For this purpose, a 3Mn-0.2C MMS with lower contents of alloying elements was selected. Microstructures and alloying element distributions of the thermomechanically processed samples were analyzed via EBSD and EPMA. The results showed that the DIFT occurred in the thermomechanically processed 3Mn-0.2C MMS in the α + γ region. Characteristic multiphase microstructures consisting isolated martensite and fine-grained equiaxed ferrite concomitant with fine islands of retained austenite dispersed between ferrite grains can be obtained. During the DIFT, the enhanced nucleation of ferrite at α/γ interfaces can not only increase the ferrite nucleation density but also facilitate extensive impingement among the neighboring grains. Formation of ultrafine ferrite via the DIFT in MMS can be interpreted in terms of unsaturated nucleation and limited growth. In addition, partitioning of Mn between the ultrafine ferrite and austenite is accelerated during the DIFT such that a large number of Mn-enriched fine islands of austenite are left untransformed at the α/α grain boundaries or at triple junctions. These islands of austenite are considered to play critical roles not only for obtaining retained austenite at room temperature but also for conserving the ultrafine microstructure of the DIFT during the post-deformation processing.
Yi SUN , Qinyuan ZHENG , Baojia HU , Ping WANG , Chengwu ZHENG , Dianzhong LI . Mechanism of Dynamic Strain-Induced Ferrite Transformation in a 3Mn-0.2C Medium Mn Steel[J]. Acta Metall Sin, 2022 , 58(5) : 649 -659 . DOI: 10.11900/0412.1961.2021.00192
| 1 | Wei Y J, Li Y Q, Zhu L C, et al. Evading the strength-ductility trade-off dilemma in steel through gradient hierarchical nanotwins [J]. Nat. Commun., 2014, 5: 3580 |
| 2 | Bouaziz O, Zurob H, Huang M X. Driving force and logic of development of advanced high strength steels for automotive applications [J]. Steel Res Int., 2013, 84: 937 |
| 3 | Tang D, Zhao Z Z, Mi Z L, et al. Advanced High Strength Strip Steel for Automobile [M]. Beijing: Metallurgical Industry Press, 2016: 1 |
| 3 | 唐 荻, 赵征志, 米振莉 等. 汽车用先进高强板带钢 [M]. 北京: 冶金工业出版社, 2016: 1 |
| 4 | Raabe D, Sun B H, Silva A K D, et al. Current challenges and opportunities in microstructure-related properties of advanced high-strength steels [J]. Metall. Mater. Trans., 2020, 51A: 5517 |
| 5 | Fonstein N. Advanced High Strength Sheet Steels: Physical Metallurgy, Design, Processing, and Properties [M]. New York: Springer, 2015: 1 |
| 6 | Wang C Y, Chang Y, Zhou F L, et al. M3 microstructure control theory and technology of the third-generation automotive steels with high strength and high ductility [J]. Acta Metall. Sin., 2020, 56: 400 |
| 6 | 王存宇, 常 颖, 周峰峦 等. 高强度高塑性第三代汽车钢的M3组织调控理论与技术 [J]. 金属学报, 2020, 56: 400 |
| 7 | Zhao Z Z, Chen W J, Gao P F, et al. Progress and perspective of advanced high strength automotive steel [J]. J. Iron Steel Res., 2020, 32: 1059 |
| 7 | 赵征志, 陈伟健, 高鹏飞 等. 先进高强度汽车用钢研究进展及展望 [J]. 钢铁研究学报, 2020, 32: 1059 |
| 8 | Lee Y K, Han J. Current opinion in medium manganese steel [J]. Mater. Sci. Technol., 2015, 31: 843 |
| 9 | Suh D W, Kim S J. Medium Mn transformation-induced plasticity steels: Recent progress and challenges [J]. Scr. Mater., 2017, 126: 63 |
| 10 | Ma Y. Medium-manganese steels processed by austenite-reverted-transformation annealing for automotive applications [J]. Mater. Sci. Technol., 2017, 33: 1713 |
| 11 | Liu L, He B B, Huang M X. The role of transformation-induced plasticity in the development of advanced high strength steels [J]. Adv. Eng. Mater., 2018, 20: 1701083 |
| 12 | Jacques P J. Transformation-induced plasticity for high strength formable steels [J]. Curr. Opin. Solid State Mater. Sci., 2004, 8: 259 |
| 13 | Lee S, Lee S J, De Cooman B C. Austenite stability of ultrafine-grained transformation-induced plasticity steel with Mn partitioning [J]. Scr. Mater., 2011, 65: 225 |
| 14 | Cai Z H, Ding H, Misra R D K, et al. Austenite stability and deformation behavior in a cold-rolled transformation-induced plasticity steel with medium manganese content [J]. Acta Mater., 2015, 84: 229 |
| 15 | Miller R L. Ultrafine-grained microstructures and mechanical properties of alloy steels [J]. Metall. Mater. Trans., 1972, 3B: 905 |
| 16 | Zhang X L, Hou H F, Liu T, et al. Microstructure and mechanical properties of a novel heterogeneous cold-rolled medium Mn steel with high product of strength and ductility [J]. Chin. J. Mater. Res., 2019, 33: 927 |
| 16 | 张喜亮, 侯华峰, 刘 涛 等. 一种新型高强塑积异质冷轧中锰钢的力学性能 [J]. 材料研究学报, 2019, 33: 927 |
| 17 | Li Y, Li W, Min N, et al. Mechanical response of a medium manganese steel with encapsulated austenite [J]. Scr. Mater., 2020, 178: 211 |
| 18 | Ding R, Yao Y J, Sun B H, et al. Chemical boundary engineering: A new route toward lean, ultrastrong yet ductile steels [J]. Sci. Adv., 2020, 6: eaay1430 |
| 19 | He B B, Hu B, Yen H W, et al. High dislocation density-induced large ductility in deformed and partitioned steels [J]. Science, 2017, 357: 1029 |
| 20 | Hu B, Luo H W, Yang F, et al. Recent progress in medium Mn steels made with new designing strategies, a review [J]. J. Mater. Sci. Technol., 2017, 33: 1457 |
| 21 | Suh D W, Park S J, Lee T H, et al. Influence of Al on the microstructural evolution and mechanical behavior of low-carbon, manganese transformation-induced-plasticity steel [J]. Metall. Mater. Trans., 2010, 41A: 397 |
| 22 | Cai M H, Li Z, Chao Q, et al. A novel Mo and Nb microalloyed medium Mn TRIP Steel with maximal ultimate strength and moderate ductility [J]. Metall. Mater. Trans., 2014, 45A: 5624 |
| 23 | Shao C W, Hui W J, Zhang Y J, et al. Microstructure and mechanical properties of a novel cold rolled medium-Mn steel with superior strength and ductility [J]. Acta Metall. Sin., 2019, 55: 191 |
| 23 | 邵成伟, 惠卫军, 张永健 等. 一种新型高强度高塑性冷轧中锰钢的组织和力学性能 [J]. 金属学报, 2019, 55: 191 |
| 24 | Li S S, Wen P Y, Li S L, et al. A novel medium-Mn steel with superior mechanical properties and marginal oxidization after press hardening [J]. Acta Mater., 2021, 205: 116567 |
| 25 | Liu D G, Cai M H, Ding H, et al. Control of inter/intra-granular κ-carbides and its influence on overall mechanical properties of a Fe-11Mn-10Al-1.25C low density steel [J]. Mater. Sci. Eng., 2018, A715: 25 |
| 26 | Zhao J W, Jiang Z Y. Thermomechanical processing of advanced high strength steels [J]. Prog. Mater. Sci., 2018, 94: 174 |
| 27 | Essadiqi E, Jonas J J. Effect of deformation on the austenite-to-ferrite transformation in a plain carbon and two microalloyed steels [J]. Metall. Trans., 1988, 19A: 417 |
| 28 | Dong H, Sun X J. Deformation induced ferrite transformation in low carbon steels [J]. Curr. Opin. Solid State Mater. Sci., 2005, 9: 269 |
| 29 | Hurley P J, Hodgson P D. Formation of ultra-fine ferrite in hot rolled strip: Potential mechanisms for grain refinement [J]. Mater. Sci. Eng., 2001, A302: 206 |
| 30 | Wen Y Q. Ultra-Fine Grained Steels [M]. Beijing: Metallurgical Industry Press, 2003: 1 |
| 30 | 翁宇庆. 超细晶钢 [M]. 北京: 冶金工业出版社, 2003: 1 |
| 31 | Chen M M, Wu R M, Liu H P, et al. An ultrahigh strength steel produced through deformation-induced ferrite transformation and Q&P process [J]. Sci. China Technol. Sci., 2012, 55: 1827 |
| 32 | Ito A, Matsui Y, Bai Y, et al. Ferrite transformation and mechanical properties of medium manganese steel [A]. Proceedings of 1st International Conference on Automobile Steel and 3rd International Conference on High Manganese Steels [C]. Beijing: Metallurgical Industry Press, 2016: 123 |
| 33 | Hou F F, Bai Y, Shibata A, et al. Microstructure evolution during thermomechanical processing in 3Mn-0.1C medium-Mn steel [J]. Mater. Sci. Technol., 2019, 35: 2101 |
| 34 | Beladi H, Kelly G L, Hodgson P D. Ultrafine grained structure formation in steels using dynamic strain induced transformation processing [J]. Int. Mater. Rev., 2007, 52: 14 |
| 35 | Ghosh C, Aranas C, Jonas J J. Dynamic transformation of deformed austenite at temperatures above the Ae3 [J]. Prog. Mater. Sci., 2016, 82: 151 |
| 36 | Nakada N, Mizutani K, Tsuchiyama T, et al. Difference in transformation behavior between ferrite and austenite formations in medium manganese steel [J]. Acta Mater., 2014, 65: 251 |
| 37 | Shibata A, Takeda Y, Park N, et al. Nature of dynamic ferrite transformation revealed by in-situ neutron diffraction analysis during thermomechanical processing [J]. Scr. Mater., 2019, 165: 44 |
| 38 | Zheng C W, Xiao N M, Hao L H, et al. Numerical simulation of dynamic strain-induced austenite-ferrite transformation in a low carbon steel [J]. Acta Mater., 2009, 57: 2956 |
| 39 | Zheng C W, Li D Z, Lu S P, et al. On the ferrite refinement during the dynamic strain-induced transformation: A cellular automaton modeling [J]. Scr. Mater., 2008, 58: 838 |
/
| 〈 |
|
〉 |
