Characterization of the Trace Phosphorus Segregation and Mechanical Properties of Dual-Phase Steels

doi:10.1007/s40195-021-01261-x

Abstract

Abstract:

The segregation behavior of trace amount of phosphorus (P) and the mechanical properties of dual-phase (DP) steels have been systematically studied. The microstructure of DP steels is mainly composed of martensite, ferrite and nanoscale carbides. For the DP steels with different trace amounts of P (≤ 0.015 wt%), P has almost no effect on the mechanical properties. Atom probe technology (APT) analyses confirm that P segregation was only found at the precipitate/matrix interface. Moreover, the precipitates of (Ti, Mo) C are widely distributed in the ferrite, martensite and ferrite/martensite interface regions. The special segregation feature of P would not concentrate at specific regions such as ferrite/martensite interface and/or martensite lath interface, which reveals that trace amounts of P (≤ 0.015wt%) have almost no effect on the mechanical properties of DP steels. It is proved for the first time that the MC-type carbides of (Ti, Mo) C can reduce or eliminate the damage effect of P on the mechanical properties of steels, which provides a new way for the design of alloys to reduce P damage. This work will promote to increase the P content control standard in DP steels from 0.01 to 0.015 wt%, which will not change the mechanical properties, but greatly reduce the scrap rate and increase the energy efficiency of the manufacturing process.

Key words: Phosphorus, Segregation, Carbide, Mechanical properties, Atom probe tomography, Dual-phase steels

Jing Wang, Wei Li, Xiaodong Zhu, Li You, Laiqi Zhang. Characterization of the Trace Phosphorus Segregation and Mechanical Properties of Dual-Phase Steels[J]. Acta Metallurgica Sinica (English Letters), 2022, 35(2): 341-352.

Figures/Tables 14

Table 1 Chemical compositions of DP steels (wt%)

	C	Si	Mn	P	Al	Cr	Mo	Ti
Martensite tip	1.414	0.047	3.009	0.025	0.047	0.719	0.248	0.031
Ferrite tip	0.266	0.405	2.51	0.022	0.035	0.634	0.139	0.026
H-P steel	0.4174	0.4968	2.1348	0.0266	0.0024	0.3617	0.0620	0.0181

Fig. 1 Schematic diagram of specific milling area selection of APT tip containing ferrite/martensite interface and the final tip morphology is the illustration in the upper right corner

Fig. 2 Microstructures of the two DP steels: a-c L-P steel and d-f H-P steel. The phase interface between ferrite and martensite is indicated by the red dotted lines. α: ferrite. α′: martensite

Fig. 3 Topography and HRTEM images of MC-carbide: a morphology and EDX image of MC-carbide; b SAED of MC-carbide; c HRTEM image of MC-carbide; d, e FFT image of MC-carbide and ferrite matrix, respectively

Fig. 4 Tensile properties of the two DP steels stretched along the RD and TD: a YS and UTS of the two DP steels; b UEl and El of the two DP steels

Fig. 5 Fracture morphologies of the middle part of the two DP steels stretched along RD: a, b L-P steel; c, d H-P steels. C: crack, D: dimple

Fig. 6 Charpy impact toughness of L-P and H-P steels at different temperatures

Fig. 7 Morphologies of the central area of the impact fracture of the two DP steels at different temperatures: a-d fracture morphologies of L-P steel specimens at 25 °C, - 40 °C, - 80 °C and - 196 °C, respectively; e-h fracture morphologies of H-P steel specimens at 25 °C, - 40 °C, - 80 °C and - 196 °C, respectively. D: dimple; C: crack; V: void; I: inclusion; Cf: quasi-cleavage fracture

Fig. 8 Fracture morphologies of H-P steel impacted at - 196 °C: a macro-fracture morphology away from the V-notch; b macro-fracture morphology in the middle part; c macro-fracture morphology near the V-notch; d-f corresponding to a-c local area (marked by the blue box) magnification graphs, respectively

Fig. 9 APT results of martensite tip of H-P steel. a Atom maps of Fe, C, Mo, Ti and P. b 1D concentration profiles of C and P. c Reconstruction of precipitate by Mo, Ti and P iso-surfaces. d, e Concentration profiles of different elements of the precipitate calculated in the form of a proximity histogram (0 nm is the interface defined by the iso-surface of C at 20 at.%)

Table 2 Bulk compositions of martensite and ferrite tips by APT, and theoretical average element concentration of the H-P steel by chemistry analysis (at.%)

	C	Si	Mn	P	S	Al	Ti	Cr	Mo
L-P steel	0.09	0.27	2.13	0.008	0.0015	0.0209	0.0178	0.316	0.115
H-P steel	0.09	0.25	2.11	0.015	0.0014	0.0177	0.0156	0.338	0.107

Fig. 10 APT results of the ferrite tip from H-P steel. a Atom maps of Fe, C, Mo and P. b Reconstruction of clusters by iso-surfaces of C at 1.5 at.% and Mo at 0.8 at.%. c, d Concentration profiles of different elements of the cluster marked with a blue box in b calculated in the form of a proximity histogram (0 nm is the interface defined by the iso-surface of C at 1.5 at.%)

Fig. 11 Reconstructed data of F/M tip from H-P steel. a Morphology of MC-carbide located at the F/M interface. b Proximity histogram profile of MC-carbide. The one-dimensional concentration profiles of c C, d P correspond to the positions in (a), respectively. The shaded parts of different colors, respectively, represent the location of the F/M interface in different areas

Fig. 12 Schematic diagram of the effect of (Ti, Mo) C carbides on P segregation. A schematic diagram of P segregation at F/M interfaces a without and b with (Ti, Mo) C carbides

References 46

[1]	M. Calcagnotto, D. Ponge, E. Demir, D. Raabe, Mater. Sci. Eng. A 527, 2738 (2010) DOI URL
[2]	Y.G. Deng, H.S. Di, J.C. Zhang, Acta Metall. Sin. -Engl. Lett. 28, 114 (2015)
[3]	N. Fonstein, 7 - Dual-phase steels, in Automotive steels. ed. by R. Rana, S.B. Singh (Elsevier, 2017), pp. 169-216
[4]	M. Calcagnotto, Y. Adachi, D. Ponge, D. Raabe, Acta Mater. 59, 658 (2011) DOI URL
[5]	J. Kadkhodapour, A. Butz, S. Ziaei Rad, Acta. Mater. 59, 2575 (2011) DOI URL
[6]	M. Adhikary, A. Chakraborty, A. Das, Mater. Sci. Eng. A 736, 209 (2018) DOI URL
[7]	S.P. Tsai, T.C. Su, J.R. Yang, C.Y. Chen, Y.T. Wang, C.Y. Huang, Mater. Des. 119, 319 (2017) DOI URL
[8]	J.T. Liang, Z.Z. Zhao, B.Q. Guo, B.H. Sun, D. Tang, Mater. Res. Expr. 6, 026502 (2019)
[9]	Z.W. Wang, G.M. Xie, D. Wang, H. Zhang, D.R. Ni, P. Xue, B.L. Xiao, Z.Y. Ma, Acta Metall. Sin. -Engl. Lett. 33, 58 (2020)
[10]	B. Gao, R. Hu, Z. Pan, X. Chen, Y. Liu, L. Xiao, Y. Cao, Y. Li, Q. Lai, H. Zhou, J. Mater. Sci. Technol. 65, 29 (2021) DOI
[11]	H. Ashrafi, M. Shamanian, R. Emadi, E. Ghassemali, Acta Metall. Sin. -Engl. Lett. 33, 299 (2020)
[12]	D. Mclean, Grain Boundaries in Metals (Oxford University Press, 1957)
[13]	T.D. Xu, J. Mater. Sci. 22, 337 (1987) DOI URL
[14]	T. Xu, L. Zheng, K. Wang, R.D.K. Misra, Int. Mater. Rev. 58, 263 (2013) DOI URL
[15]	Y. Zhao, S.H. Song, Steel Res. Int. 89, 6 (2018)
[16]	J.R. Cowan, H.E. Evans, R.B. Jones, P. Bowen, Acta Mater. 46, 6565 (1998) DOI URL
[17]	S.H. Song, Y. Zhao, H. Si, Mater. Lett. 140, 20 (2015) DOI URL
[18]	K. Wang, H. Si, C. Yang, T. Xu, C. Shao, X. Chen, Mater. Lett. 65, 1639 (2011) DOI URL
[19]	K. Wang, M. Wang, H. Si, T. Xu, Mater. Sci. Eng. A 485, 347 (2008) DOI URL
[20]	M. Mackenbrock, H.J. Grabke, J. Mater. Sci. Technol. 8, 541 (1992) DOI URL
[21]	Y. Nishiyama, K. Onizawa, M. Suzuki, J.W. Anderegg, Y. Nagai, T. Toyama, M. Hasegawa, Acta Mater. 56, 4510 (2008) DOI URL
[22]	S.H. Song, J. Wu, L.Q. Weng, T.H. Xi, Mater. Sci. Eng. A 520, 97 (2009) DOI URL
[23]	X. Min, Y. Kimura, T. Kimura, K. Tsuzaki, Mater. Sci. Eng. A 649, 135 (2016) DOI URL
[24]	J.C. Han, J.B. Seol, M. Jafari, J.E. Kim, S.J. Seo, C.G. Park, Mater. Charact. 145, 454 (2018) DOI URL
[25]	F. Christien, R. Le. Gall, G. Saindrenan, Scr. Mater. 48, 11 (2003) DOI URL
[26]	T. Sharma, S.K. Bonagani, N.N. Kumar, I. Samajdar, V. Kain, Mater. Sci. Eng. A 725, 88 (2018) DOI URL
[27]	A. Zhang, S. Zhang, F. Liu, F. Qi, X. Yao, Y. Tan, D. Jia, W. Sun, J. Mater. Sci. Technol. 35, 1485 (2019) DOI
[28]	M.K. Miller, J. Mater. Sci. 41, 7808 (2006) DOI URL
[29]	K. Thompson, D. Lawrence, D.J. Larson, J.D. Olson, T.F. Kelly, B. Gorman, Ultramicroscopy 107, 131 (2007) PMID
[30]	Y. Sun, X.F. Li, X.Y. Yu, D.L. Ge, J. Chen, J.S. Chen, Acta Metall. Sin. -Engl. Lett. 27, 101 (2014)
[31]	A.P. Pierman, O. Bouaziz, T. Pardoen, P.J. Jacques, L. Brassart, Acta Mater. 73, 298 (2014) DOI URL
[32]	J. Samei, L. Zhou, J. Kang, D.S. Wilkinson, Int. J. Plast. 117, 58 (2019) DOI URL
[33]	T. Matsuno, T. Yoshioka, I. Watanabe, L. Alves, Int J Mech Sci 163, 105133 (2019) DOI URL
[34]	M. Calcagnotto, D. Ponge, D. Raabe, Mater. Sci. Eng. A 527, 2738 (2010) DOI URL
[35]	D. Liu, M. Luo, B. Cheng, R. Cao, J. Chen, Metall. Mater. Trans. A 49, 4918 (2018) DOI URL
[36]	Y. Zhao, X. Tong, X.H. Wei, S.S. Xu, S. Lan, X.L. Wang, Z.W. Zhang, Int. J. Plast. 116, 203 (2019) DOI URL
[37]	R. Song, D. Ponge, D. Raabe, Acta Mater. 53, 4881 (2005) DOI URL
[38]	H.F. Lan, X.H. Liu, L.X. Du, Acta Metall. Sin. -Engl. Lett. 25, 443 (2012)
[39]	G.L. Krasko, G.B. Olson, Solid State Commun. 76, 247 (1990) DOI URL
[40]	X. Li, J. Zhao, J. Wang, X. Wang, S. Liu, C. Shang, Mater. Lett. 259, 126841 (2020) DOI URL
[41]	B.L. Bramfitt, Metall. Trans. , 1, 1987 (1970) DOI URL
[42]	H.W. Yen, P.Y. Chen, C.Y. Huang, J.R. Yang, Acta Mater. 59, 6264 (2011) DOI URL
[43]	R.A. Mulford, C.J. McMahon Jr., D.P. Pope, H.C. Feng, Metall. Trans. 7, 1183 (1976) DOI URL
[44]	J. Wang, W. Li, H. Zhu, X. Zhu, L. Zhang, Mater Lett 283, 128820 (2021) DOI URL
[45]	T.D. Xu, B.Y. Cheng, Prog. Mater. Sci. 49, 109 (2004) DOI URL
[46]	S.H. Song, L.Q. Weng, Mater. Sci. Technol. 21, 305 (2005) DOI URL