New insights into the hardening and pitting corrosion mechanisms of thermally aged duplex stainless steel at 475 °C: A comparative study between 2205 and 2101 steels

doi:10.1016/j.jmst.2021.04.046

Abstract

Abstract:

In this study, the relationship between spinodal decomposition and the formation of Ni-rich clusters and G-phase in the ferrite on hardening and pitting corrosion of two thermally aged duplex stainless steels (DSSs) at 475 °C was investigated. Results indicate that, for 2205 DSS, pitting corrosion behavior is influenced by the presence and size of G-phase precipitates for longer aging times, but this contribution is masked by the advanced stage of spinodal decomposition in the ferritic structure. On the other hand, for 2101 DSS, the formation of Cr-richer nitrides impairs pitting corrosion resistance more than spinodal decomposition.

Key words: Duplex stainless steel, Spinodal decomposition, G-phase precipitation, Pitting corrosion, Hardening

R. Silva, S. Vacchi G., L. Kugelmeier C., G.R. Santos I., A. Mendes Filho A., C.C. Magalhães D., R.M. Afonso C., L. Sordi V., A.D. Rovere C.. New insights into the hardening and pitting corrosion mechanisms of thermally aged duplex stainless steel at 475 °C: A comparative study between 2205 and 2101 steels[J]. J. Mater. Sci. Technol., 2022, 98: 123-135.

Figures/Tables 18

Table 1 Chemical compositions of LDSS 2101 and DSS 2205 (wt.%).

Material	C	S	N	Cr	Ni	Mn	Mo	Si	Cu	P
LDSS 2101	0.030	0.005	0.23	21.49	1.60	4.41	0.25	0.64	0.37	0.020
DSS 2205	0.025	0.005	0.19	22.61	5.83	1.51	3.26	0.44	0.20	0.022

Fig. 1. Mean values of ferrite hardness of samples thermally aged for up to 2000 h and annealed samples.

Fig. 2. BF-TEM representative images of the ferritic matrix of LDSS 2101 thermally aged for 2000 h (a) and annealed after aging for 2000 h (b). DSS 2205 thermally aged for 2000 h representative BF-TEM observations in (c) and annealed after aging for 2000 h in (d). Their corresponding selected area diffraction patterns (SADP) are next to each image.

Table 2 EDS chemical compositions of alloying elements in the ferrite and austenite phases of solution treated samples.

Compositions (wt.%)
Element	LDSS 2101		DSS 2205
	Ferrite	Austenite	Ferrite	Austenite
Fe	68.14	69.19	64.83	64.83
Cr	21.77	19.91	23.40	20.80
Ni	1.30	1.92	4.43	6.57
Mo	0.14	0.17	3.63	2.52
Mn	4.56	5.01	1.60	1.81
Si	0.77	0.71	0.44	0.39

Fig. 3. DL-EPR curves of solution treated and annealed samples after aging at 475 °C for 2000 h: (a) LDSS 2101 and (c) DSS 2205; and their respective degrees of Cr depletion with aging time in (b) and (d).

Fig. 4. BSE-SEM micrographs of corrosion attack aspect for different thermal aging times for LDSS 2101, after DL-EPR tests.

Table 3 Chemical equilibrium composition and volumetric fraction of Cr carbides and nitrides predicted to form in the microstructure of LDSS 2101 and DSS 2205 during exposure at 475 °C and 550 °C, calculated by Thermo-Calc with TCFE7 database.

Material	Temperature	Intermetallic	Volumetric fraction (%)	Chemical composition (wt.%)
				Cr	Mo	C	N
LDSS 2101	475 °C	Carbide	0.58	70.09	18.63	5.17	—
	550 °C		0.57	68.88	17.01	5.20	—
LDSS 2101	475 °C	Nitride	2.66	78.36	5.11	—	11.32
	550 °C		2.68	80.85	3.99	—	11.38
DSS 2205	475 °C	Carbide	0.50	69.68	20.28	5.14	—
	550 °C		0.49	67.87	20.01	5.13	—
DSS 2205	475 °C	Nitride	2.23	68.93	20.07	—	10.65
	550 °C		2.23	71.92	16.86	—	10.77

Fig. 5. SE-SEM micrographs of 2000 h aged sample of LDSS 2101 after etching with 10% oxalic acid solution, detailing the specific location from which the TEM foil was taken out (a). BF-TEM foil observation of the ferrite/austenite interface and HAADF-TEM image (b) and corresponding elemental mapping of the ferrite/austenite interface (c).

Fig. 6. BSE-SEM micrographs of samples after DL-EPR tests: (a) LDSS 2101 - thermally aged sample at 475 °C for 2000 h; (b) LDSS 2101 - annealed sample after aging at 475 °C for 2000 h; (c) DSS 2205 - thermally aged sample at 475 °C for 2000 h; (d) DSS 2205 - annealed sample after aging at 475 °C for 2000 h.

Fig. 7. Anodic polarization curves for solution treated and thermally aged samples at 475 °C for 2000 h of: (a) LDSS 2101 and (b) DSS 2205.

Fig. 8. Epit mean values obtained from anodic polarization curves of LDSS 2101 and DSS 2205 after aging at 475 °C.

Fig. 9. BSE-SEM images of the surface aspect of solution treated (a, c) and aged samples at 475 °C for 2000 h (b, d) after anodic polarization tests of LDSS 2101 and DSS 2205, respectively.

Table 4 PRE-values calculated from ferrite and austenite phases of solution treated samples of LDSS 2101 and DSS 2205.

Material	PREα	PREγ
LDSS 2101	19.17	20.86
DSS 2205	36.18	31.36
DSS 2205*	35.28	31.51

Fig. 10. Anodic polarization curves of solution treated and annealed samples after thermal aging at 475 °C for up to 2000 h of: (a) LDSS 2101 and (b) DSS 2205.

Fig. 11. Epit mean values obtained from anodic polarization curves of aged and annealed post-aging samples: (a) LDSS 2101 and (b) DSS 2205.

Fig. 12. BF-TEM images detailing spinodal decomposition and corresponding elemental mappings after aging at 475 °C for 2000 h: (a) LDSS 2101 and (b) DSS 2205.

Fig. 13. BSE-SEM images of the surface aspect of annealed samples post-aging for 2000 h after anodic polarization tests: (a) LDSS 2101 and (b) DSS 2205.

Fig. 14. Schematic representation of microstructure evolution illustrating the influence of cathode/anode ratio as a function of G-phase size.

References 63

[1]	J. Olsson, M. Snis, Desalination 205 (2007) 104-113, doi: 10.1016/j.desal.2006.02.051. DOI URL
[2]	K. Chandra, R. Singhal, V. Kain, V.S. Raja, Mater. Sci. Eng. A. 527 (2010) 3904-3912, doi: 10.1016/j.msea.2010.02.069. DOI URL
[3]	B. Deng, Z. Wang, Y. Jiang, T. Sun, J. Xu, J. Li, Corros. Sci. 51 (2009) 2969-2975, doi: 10.1016/j.corsci.2009.08.015. DOI URL
[4]	L. Zhang, Y. Jiang, B. Deng, W. Zhang, J. Xu, J. Li, Mater. Charact. 60 (2009) 1522-1528, doi: 10.1016/j.matchar.2009.08.009. DOI URL
[5]	Z. Zhang, H. Zhao, H. Zhang, Z. Yu, J. Hu, L. He, J. Li, Corros. Sci. 93 (2015) 120-125, doi: 10.1016/j.corsci.2015.01.014. DOI URL
[6]	C.A. DellaRovere, F.S. Santos, R. Silva, C.A.C. Souza, S.E. Kuri, Corros. Sci. 68 (2013) 84-90, doi: 10.1016/j.corsci.2012.10.038. DOI URL
[7]	R. Silva, L.F.S. Baroni, C.L. Kugelmeier, M. B. R.Silva, S.E. Kuri, C.A.D. Rovere, Cor-ros. Sci. 116 (2017) 66-73, doi: 10.1016/j.corsci.2016.12.014.
[8]	R.N. Gunn, Duplex Stainless Steels: Microstructure, Properties and Applications, 1st Ed., Woodhead Publishing, Cambridge, UK, 1997.
[9]	J.D. Tucker, M.K. Miller, G.A. Young, Acta Mater. 87 (2015) 15-24, doi: 10.1016/j.actamat.2014.12.012. DOI URL
[10]	W. Guo, D.A. Garfinkel, J.D. Tucker, D. Haley, G.A. Young, J.D. Poplawsky, Nan-otechnology 27 (2016) 254004, doi: 10.1088/0957-4484/27/25/254004.
[11]	T.G. Lach, W.E. Frazier, J. Wang, A. Devaraj, T.S. Byun, Acta Mater. (2020), doi: 10.1016/j.actamat.2020.05.017.
[12]	K.L. Weng, H.R. Chen, J.R. Yang, Mater. Sci. Eng. A. 379 (2004) 119-132, doi: 10.1016/j.msea.2003.12.051. DOI URL
[13]	C. Pareige, J. Emo, S. Saillet, C. Domain, P. Pareige. J. Nucl. Mater. 465 (2015) 383-389, doi: 10.1016/j.jnucmat.2015.06.017. DOI URL
[14]	X. Liu, W. Lu, X. Zhang, Acta Mater 183 (2020) 51-63, doi: 10.1016/j.actamat.2019.11.008. DOI URL
[15]	S. Mburu, R.P. Kolli, D.E. Perea, S.C. Schwarm, A. Eaton, J. Liu, S. Patel, J. Bar-trand, S. Ankem, Mater. Sci. Eng. A. 690 (2017) 365-377, doi: 10.1016/j.msea.2017.03.011. DOI URL
[16]	J.D. Tucker, G.A. YoungJr., D.R. Eno, Solid State Phenom. 172-174 (2011) 331-337. doi: 10.4028/www.scientific.net/SSP.172-174.331. DOI URL
[17]	R. Silva, L.F.S. Baroni, M.B.R. Silva, C.R.M. Afonso, S.E. Kuri, C.A. Della Rovere, Mater. Charact. (2016), doi: 10.1016/j.matchar.2016.03.002.
[18]	J.J. Shiao, C.H. Tsai, J.J. Kai, J.H. Huang. J. Nucl. Mater. 217 (1994) 269-278, doi: 10.1016/0022-3115(94)90376-X. DOI URL
[19]	F. Danoix, B. Deconihout, A. Bostel, P. Auger, Surf. Sci. 266 (1992) 409-415, doi: 10.1016/0039-6028(92)91054-F. DOI URL
[20]	J.E. Brown, G.D.W. Smith, Surf. Sci. 246 (1991) 285-291, doi: 10.1016/0039-6028(91)90428-U. DOI URL
[21]	F. Danoix, P. Auger, Mater. Charact. 44 (2000) 177-201, doi: 10.1016/S1044-5803(99)00048-0. DOI URL
[22]	M.K. Miller, I.M. Anderson, J. Bentley, K.F. Russell, Appl. Surf. Sci. 94-95 (1996) 391-397, doi: 10.1016/0169-4332(95)00402-5. DOI URL
[23]	K.H. Lo, C.H. Shek, J.K.L. Lai, Mater. Sci. Eng. R Reports. 65 (2009) 39-104, doi: 10.1016/j.mser.2009.03.001. DOI URL
[24]	Y. Chen, X. Dai, X. Chen, B. Yang, Mater. Charact. 149 (2019) 74-81, doi: 10.1016/j.matchar.2019.01.012. DOI URL
[25]	F. Danoix, P. Auger, D. Blavette, Surf. Sci. 266 (1992) 364-369, doi: 10.1016/ 0039-6028(92)91047-F. DOI URL
[26]	S.L. Li, H.L. Zhang, Y.L. Wang, S.X. Li, K. Zheng, F. Xue, X.T. Wang, Mater. Sci. Eng. A. 564 (2013) 85-91, doi: 10.1016/j.msea.2012.11.046. DOI URL
[27]	H.M. Chung, T.R. Leax, Mater. Sci. Technol. 6 (1990) 249-262, doi: 10.1179/026708390790191170. DOI URL
[28]	R. Badyka, G. Monnet, S. Saillet, C. Domain, C. Pareige. J. Nucl. Mater. 514 (2019) 266-275, doi: 10.1016/j.jnucmat.2018.12.002. DOI URL
[29]	Y. Chen, B. Chen, F. Dong, B. Yang, S. Li, X. Yu, Eng. Fail. Anal. 83 (2018) 1-8, doi: 10.1016/j.engfailanal.2017.09.005. DOI URL
[30]	Y. Chen, B. Yang, Y. Zhou, Y. Wu, H. Zhu, Acta Mater 197 (2020) 172-183, doi: 10.1016/j.actamat.2020.07.046. DOI URL
[31]	C.-.J. Park, H.S. Kwon, Corros. Sci. 44 (2002) 2817-2830, doi: 10.1016/S0010-938X(02)00079-3. DOI URL
[32]	C.-.J. Park, H.-.S. Kwon, M.M. Lohrengel, Mater. Sci. Eng. A. 372 (2004) 180-185, doi: 10.1016/j.msea.2003.12.013. DOI URL
[33]	F. Zanotto, V. Grassi, A. Balbo, C. Monticelli, C. Melandri, F. Zucchi, Corros. Sci. 130 (2018) 22-30, doi: 10.1016/j.corsci.2017.10.024. DOI URL
[34]	F. Zanotto, V. Grassi, M. Merlin, A. Balbo, F. Zucchi, Corros. Sci. 94 (2015) 38-47, doi: 10.1016/j.corsci.2015.01.035. DOI URL
[35]	J.-.Y. Maetz, S. Cazottes, C. Verdu, F. Danoix, X. Kléber, Microsc. Microanal. 22 (2016) 463-473, doi: 10.1017/S1431927616000167. DOI URL
[36]	J.-.O. Andersson, E. Alfonsson, C. Canderyd, H.L. Groth, Proc Stainl. Steel World Conf. (2010) 1-23.
[37]	S. Cazottes, V. Massardier, R. Danoix, D. Rolland, S. Cissé, F. Danoix, Materialia,(2020) 100854, doi: 10.1016/j.mtla.2020.100854.
[38]	F. Danoix, P. Bas, J.P. Massoud, M. Guttmann, P. Auger, Appl. Surf. Sci. 67 (1993) 348-355, doi: 10.1016/0169-4332(93)90337-B. DOI URL
[39]	F. Iacoviello, F. Casari, S. Gialanella, Corros. Sci. 47 (2005) 909-922, doi: 10. 1016/j.corsci.2004.06.012. DOI URL
[40]	A.P. Majidi, M.A. Streicher, Corrosion 40 (1984) 584-593, doi: 10.5006/1.3581921. DOI URL
[41]	V. Shamanth, K.S. Ravishankar, Results Phys 5 (2015) 297-303, doi: 10.1016/j.rinp.2015.10.004. DOI URL
[42]	A. Mateo, J.L. Palomino, N. Salan, L. Llanes, M. Anglada, ECF 11 -Mech. Mech. Damage Fail 1 (1996).
[43]	Standard ASTM, ASTM, International, West Conshohocken (2018) G61-G86, doi: 10.1520/G0061-86R18.2.
[44]	R. Badyka, S. Saillet, C. Domain, C. Pareige. J. Nucl. Mater. 542 (2020) 152530, doi: 10.1016/j.jnucmat.2020.152530. DOI URL
[45]	J.W. Gahn, Acta Metall 11 (1963) 1275-1282, doi: 10.1016/0001-6160(63)90022-1. DOI URL
[46]	G.E. Dieter, New York, 1986.
[47]	S.C. Schwarm, S. Mburu, R.P. Kolli, D.E. Perea, S. Ankem, Mater. Sci. Eng. A. 720 (2018) 130-139, doi: 10.1016/j.msea.2018.02.058. DOI URL
[48]	E.B. Melo, R. Magnabosco,. (2015) 1701. doi: 10.5006/1701.
[49]	A. Pardo, M.C. Merino, A.E. Coy, F. Viejo, M. Carboneras, R. Arrabal, Acta Mater 55 (2007) 2239-2251, doi: 10.1016/j.actamat.2006.11.021. DOI URL
[50]	T. Steiner, E.J. Mittemeijer. J. Mater. Eng. Perform. 25 (2016) 2091-2102, doi: 10.1007/s11665-016-2048-x. DOI URL
[51]	F.G. Wasserman, S.S.M. Tavares, J.M. Pardal, F.B. Mainier, R.A. Faria, C.S. Nunes, REM 66 (2) (2013) 193-200.
[52]	G.S. Frankel. J. Electrochem. Soc. 145 (1998) 2186, doi: 10.1149/1.1838615. DOI URL
[53]	K. Chan, S. Tjong, Materials (Basel) 7 (2014) 5268-5304, doi: 10.3390/ma7075268. DOI URL
[54]	Z. Wei, J. Laizhu, H. Jincheng, S. Hongmei, Mater. Charact. 60 (2009) 50-55, doi: 10.1016/j.matchar.2008.07.002. DOI URL
[55]	L. Zhang, W. Zhang, Y. Jiang, B. Deng, D. Sun, J. Li, Electrochim. Acta. 54 (2009) 5387-5392, doi: 10.1016/j.electacta.2009.04.023. DOI URL
[56]	A.U. Malik, N.A. Siddiqi, S. Ahmad, I.N. Andijani, Corros. Sci. 37 (1995) 1521-1535, doi: 10.1016/0010-938X(95)00043-J.
[57]	Y. Jiang, T. Sun, J. Li, J. Xu. J. Mater. Sci. Technol. 30 (2014) 179-183, doi: 10.1016/j.jmst.2013.12.018. DOI URL
[58]	Y. Guo, T. Sun, J. Hu, Y. Jiang, L. Jiang, J. Li. J. Alloys Compd. 658 (2016) 1031-1040, doi: 10.1016/j.jallcom.2015.10.218. DOI URL
[59]	Z. Zhang, H. Zhang, H. Zhao, J. Li, Corros. Sci. 103 (2016) 189-195, doi: 10.1016/j.corsci.2015.11.018. DOI URL
[60]	D.-.W. Jiang, C.-.S. Ge, X.-.J. Zhao, J. Li, L.-.L. Shi, X.-.S. Xiao, J. Iron Steel Res. Int. 19 (2012) 50-56, doi: 10.1016/S1006-706X(12)60059-4.
[61]	H. Tian, X. Cheng, Y. Wang, C. Dong, X. Li, Electrochim. Acta. 267 (2018) 255-268, doi: 10.1016/j.electacta.2018.02.082. DOI URL
[62]	X.G. Zhang, in: Uhlig’s Corros, Handb. Third Ed, 2011, pp. 123-143, doi: 10.1002/9780470872864.ch10.
[63]	C. Örnek, D.L. Engelberg, Corros. Sci. 99 (2015) 164-171, doi: 10.1016/j.corsci.2015.06.035. DOI URL