Strengthening of Ultrafine Lamellar-Structured Martensite Steel via Tempering-Induced Nanoprecipitation

doi:10.1007/s40195-022-01420-8

Abstract

Abstract:

An ultrafine lamellar-structured martensite steel fabricated by heavy warm rolling (HWR) has shown an excellent combination of strength and ductility. By appending tempering at 400 °C to HWR, we show that the comprehensive mechanical property of a lamellar-structured low-carbon martensite steel can be further improved to reach a yield strength of ~ 1.8 GPa, an ultimate tensile strength of ~ 2.0 GPa and a total elongation of ~ 9.3%. This is achieved by tempering the HWR steel from 300 to 750 °C, and the optimum tempering temperature is thus obtained. We find that the tempered ultrafine lamellar martensite contains high-density nanoprecipitates dispersed within the aligned martensite laths with reduced crystallographic variations. The ultrahigh strength of the steel is rationalized as mainly the result of grain boundary strengthening and precipitation strengthening, which contribute to yield stress by 610 MPa and 440 MPa, respectively. The good ductility is believed to be closely related to the capacity of the tempered grains to accommodate dense dislocations upon plastic deformation. The present thermomechanical processing provides a feasible routine for producing steels with ultrahigh-strength and good-ductility.

Key words: Low-carbon steel, Heavy warm-rolling, Ultrafine lamellar-structured martensite, Precipitation strengthening, Mechanical property

Xinbo Ji, Liming Fu, Han Zheng, Jian Wang, Hengchang Lu, Wei Wang, Mao Wen, Han Dong, Aidang Shan. Strengthening of Ultrafine Lamellar-Structured Martensite Steel via Tempering-Induced Nanoprecipitation[J]. Acta Metallurgica Sinica (English Letters), 2022, 35(11): 1812-1824.

Figures/Tables 13

Table 1 Chemical composition of the martensite steel in this research (wt%)

C	Si	Mn	Cr	W	V	Nb	Co	Ta	Nd	Fe
0.08	0.23	0.25	11.5	3.15	0.24	0.08	2.96	0.08	0.04	Bal.

Fig. 1 a CCT diagram of the low-carbon steel calculated by JmatPro-7.0, b schematic diagram of thermomechanical processes. DQ direct quenching, HWR heavy warm rolling, WQ water quenching

Fig. 2 a XRD profiles of DQ, HWR and PT samples tempered at 300-750 °C, b the magnified (211) profiles in a

Fig. 3 SEM images of DQ, HWR and PT samples: a DQ, b HWR, c PT-300, d PT-400, e PT-700, and f PT-750. g Number density and area fraction of nanoprecipitates as a function of tempering temperature. h EDS analysis of spherical nanoprecipitates at grain boundaries. Abbreviation: PAGB-PA grain boundary, as indicated by white arrows. α′—martensite, red arrows and blue arrows indicate nanoprecipitates distributed in ultra-fine α′ martensite lath and at grain boundaries. White arrows indicate the PAGBs

Table 2 Width of ULS martensite and the evolution of nanoprecipitates via different temperature tempering

Samples	Effective grain size (μm)	Precipitates
Samples	Effective grain size (μm)	Size (nm)	Number density (μm^-2)	Area fraction (%)
DQ	26.5	12.2 ± 5	0.09	0.05
HWR	0.53	10.2 ± 6	0.13	0.07
PT-300	0.92	12.1 ± 8	1.21	1.69
PT-400	1.27	18.9 ± 14	1.74	4.72
PT-500	1.48	53.4 ± 26	2.37	4.57
PT-600	1.64	119 ± 46	3.92	6.17
PT-700	2.13	153 ± 56	4.44	9.77
PT-750	2.21	193 ± 59	6.68	10.7

Fig. 4 BF TEM micrographs showing a the ultra-fine α′ martensite lath after HWR, b ultra-fine α′ martensite laths parallel to RD, with insets showing a magnified ultra-fine α′ martensite lath and corresponding SAED pattern. Abbreviation: PAGB-PA grain boundary, as indicated by white arrows. α′—martensite

Fig. 5 Microstructures of PT-400. a BF TEM micrograph. b BF TEM images of magnified ultra-fine α′ martensite lath displaying the spherical and needle-like nanoprecipitates around dislocations. Orange dotted lines outline the PAGBs. c Magnified ultra-fine α′ martensite lath displaying tons of nanoprecipitates dispersed in ultra-fine α′ martensite laths and EDS images showing Cr distribution in (c) and Fe, W, Ta and C distributions in the region outlined by the red dotted square. Abbreviation: PAGB-PA grain boundary, as indicated by white arrows. α′—martensite

Fig. 6 a HRTEM image taken from Fig. 5b displaying numerous nanoprecipitates formed in a ultra-fine α′ martensite lath, whose size is less than 10 nm. b-d FFT patterns of nanoprecipitates taken from the ultra-fine α′ martensite lath in (a)

Table 3 Integrated intensity ratio and FWHM of diffraction peaks of samples with different temperature tempering

Processing state	Integrated intensity				FWHM		Lattice Strain \(\left\langle {e^{2} } \right\rangle\) (%)	Dislocation density (10¹⁵ m^-2)	Lattice parameter (Å)
Processing state	(110)	(200)	(211)	(220)	(211)	(110)		Dislocation density (10¹⁵ m^-2)	Lattice parameter (Å)
Standard PDF card 04-	100	20.0	30.0	10.0
DQ	100	17.6	33.8	8.1	0.706	0.399	3.64	0.986	2.8782
HWR	100	9.0	24.8	9.9	0.504	0.287	5.31	3.316	2.8679
PT-300	100	2.6	12.3	8.4	0.865	0.429	3.76	1.873	2.8664
PT-400	100	4.6	15.8	16.9	0.794	0.436	3.28	1.116	2.8656
PT-500	100	4.5	17.8	12.8	0.772	0.405	3.46	0.927	2.8634
PT-600	100	2.9	13.0	8.8	0.728	0.375	2.39	0.689	2.8621
PT-700	100	8.4	28.2	14.1	0.640	0.314	1.72	0.585	2.8579
PT-750	100	6.0	24.8	9.7	0.529	0.301	0.61	0.429	2.8568

Table 4 Calculated contributions of each strengthening mechanism in HWR and PT samples and the experimental yield stress

Samples	Calculated strengthening contribution				σ_cal	σ_exp
Samples	σ_gr	σ_p	σ_ds	σ₀	σ_cal	σ_exp
HWR	~ 650	-	~ 718	~ 54	~ 1422	1343
PT-400	~ 610	~ 443	~ 417	~ 38	~ 1508	1805
PT-700	~ 580	~ 124	~ 301	~ 19	~ 1024	1060

Fig. 7 Phase images of the HWR and PT-400 and PT-700 samples in a, b, c, respectively. KAM images of the HWR and PT-400 and PT-700 samples in d, e, f, respectively. HAGB high-angle grain boundary

Fig. 8 a Typical tensile engineering stress-strain and b true stress-strain curves of the DQ, HWR and PT samples tempered at 300-750 °C for 1 h and tested at a strain rate of 10-4 s-1 at room temperature. c σts, σy and ε of the HWR and PT samples as a function of tempering temperature. d Microhardness of the DQ, HWR and PT samples as a function of tempering temperature

Fig. 9 Tensile fracture morphologies of a DQ, b HWR, c PT-400, d PT-700 samples

References 53

[1]	X.B. Ji, L.M. Fu, H. Zheng, J. Peng, W. Wang, A.D. Shan, Mater. Sci. Eng. A 826, 141977 (2021) DOI URL
[2]	H. Beladi, I.B. Timokhina, S. Mukherjee, P.D. Hodgson, J. Iron Steel Res. Int. 59, 218 (2011)
[3]	M.H. Cai, S.S. Dhinwal, Q.H. Han, Q. Chao, P.H. Hodgson, Mater. Sci. Eng. A 583, 205 (2013) DOI URL
[4]	R. Song, D. Ponge, D. Raabe, J.G. Speer, D.K. Matlock, Mater. Sci. Eng. A 441, 1 (2006) DOI URL
[5]	R.Z. Valiev, Y.V. Lvanisenko, E.F. Rauch, B. Baudelet, Acta Mater. 44, 4705 (1996) DOI URL
[6]	H.S. Dong, I. Kim, J. Kim, K.T. Park, Acta Mater. 49, 1285 (2001) DOI URL
[7]	D.H. Shin, B.C. Kim, K.T. Park, W.Y. Chaoo, Acta Mater. 48, 3245 (2000) DOI URL
[8]	B.B. He, B. Hu, H.W. Yen, G.J. Cheng, Z.K. Wang, H.W. Luo, M.X. Huang, Science 357,1029 (2017) DOI PMID
[9]	Z. Han, L.M. Fu, Z.Y. Li, X.B. Ji, Q.J. Wang, W. Wang, A.D. Shan, Mater. Today Commun. 21, 100646 (2019)
[10]	N. Tsuchida, H. Nakano, T. Okamoto, T. Inoue, Mater. Sci. Eng. A 626, 441 (2015) DOI URL
[11]	X.M. Guo, S.C. Liu, J.J. Xu, S. Wang, L.M. Fu, Z. Chai, H. Lu, Mater. Sci. Eng. A 824, 141827 (2021) DOI URL
[12]	A.G. Kalashami, A. Kermanpur, A. Najafizadeh, Y. Mazaheri, Mater. Sci. Eng. A 658, 355 (2016) DOI URL
[13]	H.W. Luo, X.H. Wang, Z.B. Liu, Z.Y. Yang, J. Mater. Sci. Technol. 51, 130 (2020) DOI URL
[14]	M.X. Yang, Y. Pan, F.P. Yuan, Y.T. Zhu, X.L. Wu, Mater. Res. Lett. 4, 145 (2016) DOI URL
[15]	H. Kitahara, R. Ueji, M. Ueda, N. Tsuji, Y. Minamino, Mater. Charact. 54, 378 (2005) DOI URL
[16]	Z.Y. Li, L.M. Fu, J. Peng, H. Zheng, X.B. Ji, Y.L. Sun, S. Ma, A.D. Shan, Mater. Charact. 159, 109989 (2020) DOI URL
[17]	S.H. Jiang, H. Wang, Y. Wu, X.J. Liu, H.H. Chen, M.J. Yao, B. Gault, D. Ponge, D. Raabe, A. Hirata, M.W. Chen, Y.D. Wang, Z.P. Lu, Nature 544,460 (2017) DOI URL
[18]	Z. Shang, J. Ding, C. Fan, M. Song, J. Li, Q. Li, S. Xue, K.T. Hurtwig, X. Zhang, Acta Mater. 169, 209 (2019) DOI
[19]	A.R. Cox, P. Jones, J. Mater. Sci. 4, 890 (1969) DOI URL
[20]	M. Calcagnotto, D. Ponge, D. Raabe, ISIJ Int. 48, 1069 (2008)
[21]	M. Calcagnotto, Y. Adachi, D. Ponge, D. Raabe, Acta Mater. 59, 658 (2011) DOI URL
[22]	L.F. Lv, L.M. Fu, S. Ahmad, A.D. Shan, Mater. Sci. Eng. A 704, 469 (2017) DOI URL
[23]	H.L. Zhang, M.Y. Sun, Y.X. Liu, D.P. Ma, B. Xu, M.X. Huang, D.Z. Li, Y.Y. Li, Acta Mater. 211, 116878 (2021) DOI URL
[24]	Z.W. Wang, W.J. Lu, H. Zhao, C.H. Liebscher, J.Y. He, D. Ponge, D. Raabe, Z.M. Li, Sci. Adv. 6, 9543 (2020)
[25]	M.C. Niu, L.C. Yin, K. Yang, J.H. Luan, W. Wang, Z.B. Jiao, Acta Mater. 209, 116788 (2021) DOI URL
[26]	B.B. Zhang, F.K. Yan, M.J. Zhao, N.R. Tao, K. Lu, Acta Mater. 151, 310 (2018) DOI URL
[27]	S.S. Xu, Y. Zhao, D. Chen, L.W. Sun, Z.W. Zhang, Int. J. Plast. 113, 99 (2018) DOI URL
[28]	H. Beladi, L.B. Timokhina, S. Mukherjee, P.D. Hodgson, Acta Mater. 59, 4186 (2011) DOI URL
[29]	Y. Adachi, M. Wakita, H. Beladi, P.D. Hodgsom, Acta Mater. 55, 4925 (2007) DOI URL
[30]	H. Gleiter, Acta Mater. 48, 1 (2000) DOI URL
[31]	M.M. Wang, C.C. Tasan, D. Ponge, A. Kostka, D. Raabe, Acta Mater. 79, 268 (2014) DOI URL
[32]	R. Song, D. Ponge, D. Raabe, R. Kaspar, Acta Mater. 53, 845 (2005) DOI URL
[33]	H. Zheng, L.M. Fu, X.B. Ji, Z.Y. Li, Y.L. Sun, S.X. Zhao, W. Wang, A.D. Shan, Acta Merall. Sin. Engl. Lett. 33, 1645 (2020)
[34]	S.Z. Li, Z. Eliniyaz, L.T. Zhang, F. Sun, Y.Z. Shen, A.D. Shan, Mater. Charact. 73, 144 (2012) DOI URL
[35]	L. Alexander, Elbert, X-Ray Spectrometry, 2nd edn. (Springer, New York, 1974), p. 960
[36]	Y.H. Zhao, H.W. Sheng, K. Lui, Acta Mater. 49, 365 (2001) DOI URL
[37]	D. Raynor, J.M. Silcock, Met. Sci. J. 4, 121 (1970) DOI URL
[38]	M. Calcagnotto, D. Ponge, E. Demir, D. Raabe, Mater. Sci. Eng. A 527, 2738 (2010) DOI URL
[39]	J. Sun, Y.T. Zhang, P. Wang, Z.F. Ye, D.Z. Li, Acta Metall. Sin. Engl. Lett. 27, 573 (2014)
[40]	E. Abbasi, Q. Luo, D. Owens, Acta Metall. Sin. Engl. Lett. 32, 74 (2019)
[41]	Y. Wang, J. Sun, T. Jiang, Y. Sun, S. Guo, Y. Liu, Acta Mater. 158, 247 (2018) DOI URL
[42]	J.J. Sun, Y.N. Liu, Y.T. Zhu, F.L. Lian, H.J. Liu, T. Jiang, S.W. Guo, W.Q. Liu, X.B. Ren, Sci. Rep. 7, 6956 (2017) DOI URL
[43]	J. Hu, L.X. Du, H. Xie, P. Yu, R.D.K. Misra, Mater. Sci. Eng. A 605, 186 (2014) DOI URL
[44]	F. Abe, Struct. Alloys Power Plants 9, 250 (2014)
[45]	K. Maruyama, K. Sawada, J.I. Koike, ISIJ Int. 41, 641 (2001) DOI URL
[46]	L. Zhang, W. Wang, M.B. Shahzad, Y.Y. Shan, K. Yang, Acta Metall. Sin. Engl. Lett. 32, 1161 (2019)
[47]	T. Gladman, Met. Sci. J. 15, 30 (1999)
[48]	M.A. Meyers, K.K. Chawla, Mater. Today 8, 83 (2005)
[49]	D.N. Seidman, E.A. Marquis, D.C. Dunand, Acta Mater. 50, 4021 (2002) DOI URL
[50]	H. Ashrafi, M. Shamanian, R. Emadi, E. Ghassemali, Acta Metall. Sin. Engl. Lett. 33, 299 (2020)
[51]	Y.G. Deng, H.S. Di, J.C. Zhang, Acta Metall. Sin. Engl. Lett. 28, 1141 (2015)
[52]	P.F. Gao, W.J. Chen, F. Li, B.J. Ning, Z.Z. Zhao, Acta Metall. Sin. Engl. Lett. 33, 1657 (2020)
[53]	G. Krauss, Mater. Sci. Eng. A 273, 40 (1999)