Influence of Microstructural Evolution on the Hot Deformation Behavior of an Fe-Mn-Al Duplex Lightweight Steel

doi:10.1007/s40195-017-0655-7

Abstract

Abstract:

The hot deformation behavior of Fe-26Mn-6.2Al-0.05C steel was studied by experimental hot compression tests in the temperature range of 800-1050 °C and strain rate range of 0.01-30 s^-1 on a Gleeble-3500 thermal simulation machine. The microstructural evolution during the corresponding thermal process was observed in situ by confocal laser scanning microscopy. Electron backscattered diffraction and transmission electron microscopy analyses were carried out to observe the microstructural morphology before and after the hot deformation. Furthermore, interrupted compression tests were conducted to correlate the microstructural characteristics and softening mechanisms at different deformation stages. The results showed that hot compression tests of this steel were all carried out on a duplex matrix composed of austenite and δ-ferrite. As the deformation temperature increased from 800 to 1050 °C, the volume fraction of austenite decreased from 70.9% to 44.0%, while that of δ-ferrite increased from 29.1% to 56.0%. Due to the different stress exponents (n) and apparent activation energies (Q), the generated strain was mostly accommodated by δ-ferrite at the commencement of deformation, and then both dynamic recovery and dynamic recrystallization occurred earlier in δ-ferrite than in austenite. This interaction of strain partitioning and unsynchronized softening behavior caused an abnormal hot deformation behavior profile in the Fe-Mn-Al duplex steel, such as yield-like behavior, peculiar work-hardening behavior, and dynamic softening behavior, which are influenced by not only temperature and strain rate but also by microstructural evolution.

Key words: Microstructural evolution, Dual-phase steel, Lightweight component, Hot deformation, Dynamic recrystallization

Li-Xiong Xu, Hui-Bin Wu, Xin-Tian Wang. Influence of Microstructural Evolution on the Hot Deformation Behavior of an Fe-Mn-Al Duplex Lightweight Steel[J]. Acta Metallurgica Sinica (English Letters), 2018, 31(4): 389-400.

Figures/Tables 12

Fig. 1 True stress-strain curves at different deformation temperatures and strain rates: a 0.01 s-1, b 0.1 s-1, c 1 s-1, d 10 s-1, e 30 s-1

Fig. 2 Dependence of characteristic stresses on: a deformation temperatures at a strain rate of 1 s-1, b strain rates at a deformation temperature of 1000 °C

Fig. 3 Dependence of the peak stress on: a strain rates, b deformation temperatures, c the Zener-Hollomon parameters

Fig. 4 Initial microstructure of the specimen before hot compression: a SEM image, b combined image of grain boundary map and color code phase map measured by the EBSD, with the austenite (fcc) shown in blue and δ-ferrite (bcc) in red

Fig. 5 CSLM in situ observations of the tested steel at a 0.03 s and 24.2 °C, b 441.5 s and 1107.1 °C, c 545.5 s and 1099 °C, d 618.7 s and 1050.1 °C, e 679.9 s and 1000.0 °C, f 739.5 s and 950.0 °C, g 797.7 s and 900.0 °C, h 858.6 s and 850.2 °C, i 917.6 s and 800.3 °C

Fig. 6 Dependence of the volume fractions of austenite and δ-ferrite on the temperature during the cooling process in CSLM testing

Fig. 7 EBSD analysis (showing austenite in blue, δ-ferrite in red, HABs in black solid lines, and MTs in yellow solid lines) of the duplex microstructure of the specimens deformed at: a 0.01 s-1 and 850 °C, b 0.01 s-1 and 950 °C, c 0.01 s-1 and 1050 °C, d 10 s-1 and 850 °C, e 10 s-1 and 950 °C, f 30 s-1 and 1050 °C

Fig. 8 True stress-strain curves of specimens interruptedly compressed at 900 °C and 1 s-1 at interrupted strains of 0.025, 0.112, 0.3, and 0.6

Fig. 9 a EBSD analysis (showing austenite in blue, δ-ferrite in red, and LABs in white solid lines). b TEM image of the microstructure of the specimen after the compression was interrupted at a strain of 0.025

Fig. 10 EBSD analysis (showing austenite in blue, δ-ferrite in red, LABs in white solid lines, and HABs in black solid lines) and TEM image of the microstructure after the compression was interrupted at strains of a, b 0.112, c, d 0.3

Fig. 11 Dependence of a work-hardening degree, b dynamic softening degree on the deformation temperatures and strain rates

Fig. 12 a EBSD analysis (showing austenite in blue, δ-ferrite in red, and HABs in black solid lines). b TEM image of the microstructure of the specimen after the compression was interrupted at a strain of 0.6

References

[1]	W. Yu, L.X. Xu, Y. Zhang, B. Wang, C.Y. He, E.T. Dong, Trans. Mater. Heat Treat. 36(10), 261(2015)
[2]	L.J. Wang, W. Yu, H.B. Wu, Q.W. Cai, Q.G. Qi, Heat Treat. Met. 35(7), 5(2010)
[3]	C.H. Seo, K.H. Kwon, K. Choi, K.H. Kim, J.H. Kwak, S. Lee, N.J. Kim, Scr. Mater. 66(8), 519(2012)
[4]	Q. Yang, J.F. Wang, Y. Cong, L. Wang, Baosteel Technol. 3, 1(2015)
[5]	Q. Yang, J.F. Wang, Y. Cong, L. Wang, Baosteel Technol. 4, 1(2015)
[6]	Y.H. Yang, B. Yan, Mater. Sci. Eng. A 579, 194 (2013)
[7]	L. Duprez, B.C. De Cooman, N. Akdut, Metall. Mater. Trans. A 33(7), 1931 (2002)
[8]	G.W. Fan, J. Liu, P.D. Han, G.J. Qiao, Mater. Sci. Eng. A 515(1), 108 (2009)
[9]	O. Balancin, W.A.M. Hoffmann, J.J. Jonas, Metall. Mater. Trans. A 31(5), 1353 (2000)
[10]	D.J. Seol, Y.M. Won, T. Yeo, K.H. Oh, J.K. Park, C.H. Yim, ISIJ Int. 39(1), 91(1999)
[11]	A.S. Hamada, L.P. Karjalainen, M.C. Somani, R.M. Ramadan, Mater. Sci. Forum 550, 217 (2007)
[12]	F.Q. Yang, R.B. Song, L.F. Zhang, C. Zhao, Proc. Eng. 81, 456(2014)
[13]	X.F. Zhang, H. Yang, D.P. Leng, L. Zhang, Z.Y. Huang, G. Chen, J. Iron. Steel Res. Int. 23(9), 963(2016)
[14]	Z.J. Miao, A.D. Shan, W. Wei, L.U. Jun, W.L. Xu, H.W. Song, Trans. Nonferrous Met. Soc. China 21(2), 236 (2011)
[15]	A. Pinol-Juez, A. Iza-Mendia, I. Gutierrez, Metall. Mater. Trans. A 31(6), 1671 (2000)
[16]	B.S. Xie, Q.W. Cai, W. Yu, L.X. Xu, Z. Ning, Acta Metall. Sin . (Engl. Lett.) 30(3), 250(2017)
[17]	J. Chen, H.T. Li, J.P. Hu, W.H. Yu, Hot Working Technol. 43(9), 64(2014)
[18]	T. Yan, E.L. Yu, Y.Q. Zhao, Iron Steel 48(9), 58 (2013)
[19]	L. Chen, L.M. Wang, X.J. Du, X. Liu, Acta Metall. Sin. 46, 52(2010) (in Chinese)
[20]	B.J. Yu, X.J. Guan, L.J. Wang, Q.K. Zeng, Q.Q. Liu, Y. Cao, Acta Metall. Sin . (Engl. Lett.) 24(4), 287(2014)
[21]	B.S. Xie, Q.W. Cai, W. Yu, L.X. Xu, Z. Ning, J. Mater. Eng. Perform. 25(12), 5127(2016)
[22]	D. Samantaray, S. Mandal, C. Phaniraj, A.K. Bhaduri, Mater. Sci. Eng. A 528(29), 8565 (2011)
[23]	Z. Fei, S. Jian, X.D. Yan, J.L. Sun, J. Na, Z. Hua, Acta Metall. Sin. 50(6), 691(2014) (in Chinese)
[24]	C.L. Zhu, J.B. Zhang, C.Q. Cheng, J. Zhao, Acta Metall. Sin. 49(10), 1275(2013) (in Chinese)
[25]	C.J. Wang, K.K. Deng, S.S. Zhou, W. Liang, Acta Metall. Sin . (Engl. Lett.) 29(6), 527(2016)
[26]	G.Y. Lin, Z.F. Zhang, H. Zhang, D.S. Peng, J. Zhou, Acta Metall. Sin . (Engl. Lett.) 21(2), 109(2008)
[27]	A. Momeni, K. Dehghani, Mater. Sci. Eng. A 528(3), 1448 (2011)
[28]	Y.P. Li, R.B. Song, E.D. Wen, F.Q. Yang, Acta Metall. Sin . (Engl. Lett.) 29(5), 441(2016)
[29]	S. Kingklang, V. Uthaisangsuk, Metall. Mater. Trans. A 48(1), 95 (2017)
[30]	X. Ma, C.W. Zheng, X.G. Zhang, D.Z. Li, Acta Metall. Sin . (Engl. Lett.) 29(12), 1127(2016)
[31]	H. Farnoush, A. Momeni, K. Dehghani, J. Aghazadeh Mohandesi, H. Keshmiri, Mater. Des. 31(1), 220(2010)
[32]	J.R. Li, G. Chen, C. Lie, H. Zuo, Y.Z. Liu, Acta Metall. Sin. 50(9), 1063(2014) (in Chinese)
[33]	J. Johansson, M. Odén, Metall. Mater. Trans. A 31(6), 1557 (2000)
[34]	P. Cizek, B.P. Wynne, W.M. Rainforth, J. Phys. Conf. Ser. 26(1), 331(2006)
[35]	Y.Q. Ning, T. Wang, M.W. Fu, M.Z. Li, L. Wang, C.D. Zhao, Mater. Sci. Eng. A 642, 187 (2015)
[36]	I.S. Nikulin, N.V. Kamyshanchenko, T.B. Nikulicheva, M.V. Mishunin, K.A. Vokhmyanina, Mater. Lett. 182, 253(2016)
[37]	Z.Y. Liu, T.T. Huang, W.J. Liu, S.B. Kang, Trans. Nonferrous Met. Soc. China 26(2), 378 (2016)
[38]	D.J. Li, Y.R. Feng, S.Y. Song, Q. Liu, Q. Bai, F.Z. Ren, F.S. Shangguan, J. Alloys Compd. 618, 768(2015)
[39]	M. Ma, H. Ding, Z.Y. Tang, J.W. Zhao, Z.H. Jiang, G.W. Fan, J. Iron. Steel Res. Int. 23(3), 244(2016)
[40]	I. Alvarez-Armas, M.C. Marinelli, S. Here?ú, S. Degallaix, A.F. Armas, Acta Mater. 54(19), 5041(2006)
[41]	Y. Liu, H. Yan, X. Wang, M. Yan, Mater. Sci. Eng. A 575, 41 (2013)
[42]	A. Mohamadizadeh, A. Zarei-Hanzaki, H.R. Abedi, S. Mehtonen, D. Porter, Mater. Charact. 107, 293(2015)
[43]	D. Samantaray, S. Mandal, M. Jayalakshmi, C.N. Athreya, A.K. Bhaduri, V. Subramanya Sarma, Mater. Sci. Eng. A 598, 368 (2014)