Effects of carbon content on the microstructure and tensile properties of a low-density steel

Abstract

Carbon can change the phase components of low-density steels and influence the mechanical properties. In this study, a new method to control the carbon content and avoid the formation of δ-ferrite by decarburization treatment was proposed. The microstructural changes and mechanical characteristics with carbon content induced by decarburization were systematically examined. Crussard–Jaoul (C–J) analysis was employed to examine the work hardening characteristics during the tensile test. During decarburization by heat treatments, the carbon content within the austenite phase decreased, while Mn and Al were almost unchanged; this made the steel with full austenite transform into the austenite and ferrite dual phase. Meanwhile, (Ti,V)C carbides existed in both matrix phase and the mole fraction almost the same. In addition, the formation of other carbides restrained. Carbon loss induced a decrease in strength due to the weakening of the carbon solid solution. For the steel with the single austinite, the deformation mode of austenite was the dislocation planar glide, resulting in the formation of microbands. For the dual-phase steel, the deformation occurred by the dislocation planar glide of austenite first, with the increase in strain, the cross slip of ferrite took place, forming dislocation cells in ferrite. At the late stage of deformation, the work hardening of austinite increased rapidly, while that of ferrite increased slightly.

Keywords

low-density steels / carbon content / decarburization / strengthening mechanisms / work hardening behavior

References

[1] Chen SP, Rana R, Haldar A, Ray RK. Current state of Fe–Mn–Al–C low density steels. Prog. Mater. Sci.. 2017, 89: 345

[2] Gutierrez-Urrutia I, Raabe D. Influence of Al content and precipitation state on the mechanical behavior of austenitic high-Mn low-density steels. Scripta Mater.. 2013, 68(6): 343

[3] Kuziak R, Kawalla R, Waengler S. Advanced high strength steels for automotive industry. Arch. Civ. Mech. Eng.. 2008, 8(2): 103

[4] Gao YL, Zhang M, Wang R, Zhang XX, Tan ZL, Chong XY. Effect of temperature and time on the precipitation of κ-carbides in Fe–28Mn–10Al–0.8C low-density steels: Aging mechanism and its impact on material properties. Int. J. Miner. Metall. Mater.. 2024, 31(10): 2189

[5] Hu B, Sui H, Wen QH, Wang Z, Gramlich A, Luo HW. Review on the plastic instability of medium-Mn steels for identifying the formation mechanisms of Lüders and Portevin–Le Chatelier bands. Int. J. Miner. Metall. Mater.. 2024, 31(6): 1285

[6] Li SS, Luo HW. Medium-Mn steels for hot forming application in the automotive industry. Int. J. Miner. Metall. Mater.. 2021, 28(5): 741

[7] Wang YJ, Zhao S, Song RB, Hu B. Hot ductility behavior of a Fe–0.3C–9Mn–2Al medium Mn steel. Int. J. Miner. Metall. Mater.. 2021, 28(3): 422

[8] Wu ZQ, Ding H, Li HY, Huang ML, Cao FR. Microstructural evolution and strain hardening behavior during plastic deformation of Fe–12Mn–8Al–0.8C steel. Mater. Sci. Eng. A. 2013, 584: 150

[9] Hwang SW, Ji JH, Lee EG, Park KT. Tensile deformation of a duplex Fe–20Mn–9Al–0.6C steel having the reduced specific weight. Mater. Sci. Eng. A. 2011, 528(15): 5196

[10] Zhao C, Song RB, Zhang LF, Yang FQ, Kang T. Effect of annealing temperature on the microstructure and tensile properties of Fe–10Mn–10Al–0.7C low-density steel. Mater. Des.. 2016, 91: 348

[11] Yoo JD, Hwang SW, Park KT. Origin of extended tensile ductility of a Fe–28Mn–10Al–1C steel. Metall. Mater. Trans. A. 2009, 40(7): 1520

[12] Zhang LF, Song RB, Zhao C, Yang FQ, Xu Y, Peng SG. Evolution of the microstructure and mechanical properties of an austenite–ferrite Fe–Mn–Al–C steel. Mater. Sci. Eng. A. 2015, 643: 183

[13] Lin CL, Chao CG, Juang JY, Yang JM, Liu TF. Deformation mechanisms in ultrahigh-strength and high-ductility nanostructured FeMnAlC alloy. J. Alloys Compd.. 2014, 586: 616

[14] Etienne A, Massardier-Jourdan V, Cazottes S, et al. . Ferrite effects in Fe–Mn–Al–C triplex steels. Metall. Mater. Trans. A. 2014, 45(1): 324

[15] Choi K, Seo CH, Lee H, et al. . Effect of aging on the microstructure and deformation behavior of austenite base light-weight Fe–28Mn–9Al–0.8C steel. Scripta Mater.. 2010, 63(10): 1028

[16] Frommeyer G, Brüx U. Microstructures and mechanical properties of high-strength Fe–Mn–Al–C light-weight TRIPLEX steels. Steel Res. Int.. 2006, 77(9–10): 627

[17] Yoo JD, Park KT. Microband-induced plasticity in a high Mn–Al–C light steel. Mater. Sci. Eng. A. 2008, 496(1–2): 417

[18] Welsch E, Ponge D, Hafez Haghighat SM, et al. . Strain hardening by dynamic slip band refinement in a high-Mn lightweight steel. Acta Mater.. 2016, 116: 188

[19] Ding H, Han D, Zhang J, Cai ZH, Wu ZQ, Cai MH. Tensile deformation behavior analysis of low density Fe–18Mn–10Al–xC steels. Mater. Sci. Eng. A. 2016, 652: 69

[20] Zhang LF, Song RB, Zhao C, Yang FQ. Work hardening behavior involving the substructural evolution of an austenite–ferrite Fe–Mn–Al–C steel. Mater. Sci. Eng. A. 2015, 640: 225

[21] D. Han, H. Ding, D.G. Liu, B. Rolfe, and H. Beladi, Influence of C content and annealing temperature on the microstructures and tensile properties of Fe–13Mn–8Al–(0.7, 1.2)C steels, Mater. Sci. Eng. A, 785(2020), art. No. 139286.

[22] Zambrano OA. A general perspective of Fe–Mn–Al–C steels. J. Mater. Sci.. 2018, 53(20): 14003

[23] Kadoi K, Ueno S, Inoue H. Effects of ferrite content and concentrations of carbon and silicon on weld solidification cracking susceptibility of stainless steels. J. Mater. Res. Technol. 2023, 25: 1314

[24] Yi HL. Review on δ-transformation-induced plasticity (TRIP) steels with low density: The concept and current progress. JOM. 2014, 66(9): 1759

[25] T.H. Man, W.J. Wang, Y.H. Zhou, et al., Effect of cooling rate on the precipitation behavior of κ-carbide in Fe–32Mn–11Al–0.9C low density steel, Mater. Lett., 314(2022), art. No. 131778.

[26] Liu LB, Li CM, Yang Y, Luo ZP, Song CJ, Zhai QJ. A simple method to produce austenite-based low-density Fe–20Mn–9Al–0.75C steel by a near-rapid solidification process. Mater. Sci. Eng. A. 2017, 679: 282

[27] D.W. Kim, J. Yoo, S.S. Sohn, and S. Lee, Austenite reversion through subzero transformation and tempering of a boron-doped strong and ductile medium-Mn lightweight steel, Mater. Sci. Eng. A, 802(2021), art. No. 140619.

[28] J.L. Zhang, C.H. Hu, Y.H. Zhang, J.H. Li, C.J. Song, and Q.J. Zhai, Microstructures, mechanical properties and deformation of near-rapidly solidified low-density Fe–20Mn–9Al–1.2C–xCr steels, Mater. Des., 186(2020), art. No. 108307.

[29] A. Rosenauer, D. Brandl, G. Ressel, et al., Influence of delta ferrite on the impact toughness of a PH 13–8 Mo maraging steel, Mater. Sci. Eng. A, 856(2022), art. No. 144024.

[30] Hwang JH, Trang TTT, Lee O, Park G, Zargaran A, Kim NJ. Improvement of strength–ductility balance of B2-strengthened lightweight steel. Acta Mater.. 2020, 191: 1

[31] Ishida K, Ohtani H, Satoh N, Kainuma R, Nishizawa T. Phase equilibria in Fe–Mn–Al–C alloys. ISIJ Int.. 1990, 30(8): 680

[32] Xiong Y, Luan ZW, Zha XQ, et al. . Achieving superior strength and ductility combination in Fe–28Mn–8Al–1C low density steel by orthogonal rolling. J. Mater. Res. Technol.. 2023, 25: 6123

[33] Z. Li, Y.C. Wang, X.W. Cheng, Z.Y. Li, J.K. Du, and S.K. Li, The effect of Ti–Mo–Nb on the microstructures and tensile properties of a Fe–Mn–Al–C austenitic steel, Mater. Sci. Eng. A, 780(2020), art. No. 139220.

[34] H. Kim, D.W. Suh, and N.J. Kim, Fe–Al–Mn–C lightweight structural alloys: A review on the microstructures and mechanical properties, Sci. Technol. Adv. Mater., 14(2013), No. 1, art. No. 014205.

[35] Babu SS, Specht ED, David SA, et al. . In-situ observations of lattice parameter fluctuations in austenite and transformation to bainite. Metall. Mater. Trans. A. 2005, 36(12): 3281

[36] Y.R. Wen, L.N. Liang, F.K. Chiang, et al., Influences of manganese content and heat treatment on mechanical properties of precipitation-strengthened steels, Mater. Sci. Eng. A, 837(2022), art. No. 142724.

[37] Choi WS, Sandlöbes S, Malyar NV, et al. . Dislocation interaction and twinning-induced plasticity in face-centered cubic Fe–Mn–C micro-pillars. Acta Mater.. 2017, 132: 162

[38] Park G, Nam CH, Zargaran A, Kim NJ. Effect of B2 morphology on the mechanical properties of B2-strengthened lightweight steels. Scripta Mater.. 2019, 165: 68

[39] Sohn SS, Song H, Suh BC, et al. . Novel ultra-high-strength (ferrite+austenite) duplex lightweight steels achieved by fine dislocation substructures (Taylor lattices), grain refinement, and partial recrystallization. Acta Mater.. 2015, 96: 301

[40] Z. Li, Y.C. Wang, X.W. Cheng, J.X. Liang, and S.K. Li, Compressive behavior of a Fe–Mn–Al–C lightweight steel at different strain rates, Mater. Sci. Eng. A, 772(2020), art. No. 138700.

[41] Dumay A, Chateau JP, Allain S, Migot S, Bouaziz O. Influence of addition elements on the stacking-fault energy and mechanical properties of an austenitic Fe–Mn–C steel. Mater. Sci. Eng. A. 2008, 483–484: 184

[42] Kocks UF, Mecking H. Physics and phenomenology of strain hardening: The FCC case. Prog. Mater. Sci.. 2003, 48(3): 171

[43] L.L. Wei, G.H. Gao, J. Kim, R.D.K. Misra, C.G. Yang, and X.J. Jin, Ultrahigh strength-high ductility 1 GPa low density austenitic steel with ordered precipitation strengthening phase and dynamic slip band refinement, Mater. Sci. Eng. A, 838(2022), art. No. 142829.

[44] B. Mishra, R. Sarkar, V. Singh, et al., Microstructure and deformation behaviour of austenitic low-density steels: The defining role of B2 intermetallic phase, Materialia, 20(2021), art. No. 101198.

RIGHTS & PERMISSIONS

University of Science and Technology Beijing