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Acta Metall Sin  2017, Vol. 53 Issue (8): 983-990    DOI: 10.11900/0412.1961.2016.00545
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Effects of Nitrogen Addition on Microstructure and Grain Boundary Microchemistry of Inconel Alloy 690
Bo CHEN(), Xianchao HAO, Yingche MA, Xiangdong CHA, Kui LIU
Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
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Inconel alloy 690 is an austenitic nickel-based corrosion resistant alloy with about 30%Cr, which is considered as the most ideal steam generator tubing materials in nuclear power plants because of its superior resistance to intergranular attack (IGA). However, the existence of impurities and the addition of minor alloying elements cause significant difference of carbide morphology, microstructure and chromium depletion of Inconel alloy 690. In this work, the microstructure and grain boundary chemistry of Inconel alloy 690 with four different nitrogen contents have been investigated by SEM and TEM. Stacking fault probability (SFP) and IGA with respect to the microstructure was tested and analyzed. The results indicated that thermal treatment at 715 ℃ following solution annealing (SA) at 1080 ℃ caused a wide range of intergranular carbide morphology with the associated chromium depletion in the vicinity of grain boundaries. With the increasing of nitrogen content, the characters of the carbides ranged from thin continuous bands along boundaries to coarse discrete particles. Stacking fault probability was increased with the increasing of nitrogen content, and the value reached the peak at 100×10-6 of nitrogen content, then it dropped. The corrosion tests showed that moderate nitrogen content alloy performed favorable intergranular attack correlated with the presence of semi-continuous grain boundary carbide and chromium depletion was mitigated. The consequent nitrides were appeared in high nitrogen alloy. So, about 100×10-6 contents of nitrogen in alloy 690 is suitable by synthesis considering of carbides, nitrides and chromium depletion.

Key words:  Inconel alloy 690      microstructure      carbide      N     
Received:  05 December 2016     
ZTFLH:  TG132.32  

Cite this article: 

Bo CHEN, Xianchao HAO, Yingche MA, Xiangdong CHA, Kui LIU. Effects of Nitrogen Addition on Microstructure and Grain Boundary Microchemistry of Inconel Alloy 690. Acta Metall Sin, 2017, 53(8): 983-990.

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Alloy N C Cr Fe Ti Al Ni
690-38 0.0038 0.018 29.2 10.5 0.26 0.28 Bal.
690-100 0.0100 0.015 29.8 9.8 0.27 0.29 Bal.
690-220 0.0220 0.018 29.8 10.0 0.27 0.30 Bal.
690-330 0.0330 0.015 29.7 10.0 0.25 0.26 Bal.
Table 1  Chemical compositions of alloy 690(mass fraction / %)
Fig.1  SEM images of carbides precipitated on grain boundaries in alloy 690 with nitrogen contents of 38×10-6 (a), 100×10-6 (b), 220×10-6 (c) and 330×10-6 (d) after 1080 ℃, 10 min solution annealing and 715 ℃, 15 h thermal treatment
Fig.2  TEM images of carbides precipitated on grain boundaries in alloy 690 with nitrogen contents of 38×10-6 (a), 220×10-6 (b) and 330×10-6 (c) after 1080 ℃, 10 min solution annealing and 715 ℃, 15 h thermal treatment
Fig.3  TEM image of twin boundary carbides (a) and corresponding SAED patters of twin (b) and carbide (c) in alloy 690 with 38×10-6 nitrogen content after 1080 ℃, 10 min solution annealing and 715 ℃, 15 h thermal treatment
Fig.4  SEM images of TiN precipitates in alloy 690 with nitrogen contents of 38×10-6 (a), 100×10-6 (b), 220×10-6 (c) and 330×10-6 (d) after 1080 ℃, 10 min solution annealing and 715 ℃, 15 h thermal treatment (Arrows in Figs.4b~d show TiN precipitates)
Fig.5  TEM images showing stacking fault in alloy 690 with nitrogen contents of 38×10-6 (a), 220×10-6 (b) and 330×10-6 (c) after 1080 ℃, 10 min solution annealing and 715 ℃, 15 h thermal treatment
Fig.6  Chromium depletions of grain boundaries in alloy 690 with nitrogen contents of 38×10-6 (a) and 330×10-6 (b) after 1080 ℃, 10 min and different thermal treatment times at 715 ℃
N content / 10-6 Lowest of Cr content / % Width of Cr depletions zone / nm
38 24.6 500
100 26.4 400
220 27.2 300
330 28.6 200
Table 2  Grain boundaries chromium contents and width of Cr depletions in alloy 690 with different nitrogen contents after 1080 ℃, 10 min and 715 ℃, 15 h thermal treatment
[1] Chernoff H, Kenneth C W.Steam generator replacement overview[J]. Power Eng., 1996, 100: 25
[2] Park H B, Kim Y H, Lee B W, et al.Effect of heat treatment on fatigue crack growth rate of Inconel 690 and Inconel 600[J]. J. Nucl. Mater., 1996, 231: 204
[3] Lim M K, Oh S D, Lee Y Z.Friction and wear of Inconel 690 and Inconel 600 for steam generator tube in room temperature water[J]. Nucl. Eng. Des., 2003, 226: 97
[4] Kai J J, Liu M N.The effects of heat treatment on the carbide evolution and the chromium depletion along grain boundary of inconel 690 alloy[J]. Scr. Metall., 1989, 23: 17
[5] Kai J J, Yu G P, Tsai C H, et al.The effects of heat treatment on the chromium depletion, precipitate evolution, and corrosion resistance of INCONEL alloy 690[J]. Metall. Trans., 1989, 20A: 2057
[6] Qiu S Y, Su X W, Wen Y, et al.Effect of heat treatments on corrosion resistance of alloy 690[J]. Nucl. Power Eng., 1995, 16: 336(邱绍宇, 苏兴万, 文燕, 等. 热处理对690合金腐蚀性能影响的实验研究[J]. 核动力工程, 1995, 16: 336)
[7] Stiller K, Nilsson J, Norring K.Structure, chemistry, and stress corrosion cracking of grain boundaries in alloys 600 and 690[J]. Metall. Mater. Trans., 1996, 27A: 327
[8] Thuvander M, Stiller K. Structure and chemistry of grain boundaries in Ni-16Cr-9Fe model materials [J]. Appl. Surf. Sci. 1995; 87-88: 251
[9] Fuchs G E, Hayden S Z.The microstructure and tensile properties of mitrogen containing vacuum atomized alloy 690[J]. Scr. Metall. Mater., 1991; 25: 1483
[10] Li S, Chen B, Ma Y C, et al.Effects of nitrogen content on microstructure and mechanical property of 690[J]. Acta Metall. Sin., 2011, 47: 816(李硕, 陈波, 马颖澈等. N含量对690合金显微组织和室温力学性能的影响[J]. 金属学报, 2011, 47: 816)
[11] Schramm R E, Reed R P.Stacking fault energies of seven commercial austenitic stainless steels[J]. Metall. Trans., 1975, 6A: 1345
[12] Stoltz R E, Sande J B.The effect of nitrogen on stacking fault energy of Fe-Ni-Cr-Mn steels[J]. Metall. Trans., 1980, 11A: 1033
[13] Reed R P.Nitrogen in austenitic stainless steels[J]. JOM, 1989, 41(3): 16
[14] Airey G P.Microstructural aspects of the thermal treatment of Inconel alloy 600[J]. Metallography, 1980, 13: 21
[15] Li H, Xia S, Zhou B X, et al.Evolution of carbide morphology precipitated at grain boundaries in Ni-based alloy 690[J]. Acta Metall. Sin., 2009, 45: 195(李慧, 夏爽, 周邦新等. 镍基690合金时效过程中晶界碳化物的形貌演化[J]. 金属学报, 2009, 45: 195)
[16] Li Q, Zhou B X.A study of microstructure of alloy 690[J]. Acta Metall. Sin., 2001, 37: 8(李强, 周邦新. 690合金的显微组织研究[J]. 金属学报, 2001, 37: 8)
[17] Jiang R.Study on solidification segregation and precipitates in nitrogen-containing Alloy 690 [D]. Shenyang: Institute of Metal Research, Chinese Academy of Sciences, 2011(江荣. 含氮Inconel 690合金的凝固偏析和相析出行为研究 [D]. 沈阳: 中国科学院金属研究所, 2011)
[18] Dastur Y N, Leslie W C.Mechanism of work hardening in Hadfield manganese steel[J]. Metall. Trans., 1981, 12A: 749
[19] Wada H, Pehlke R D.Nitrogen solution and titanium nitride precipitation in liquid Fe-Cr-Ni alloys[J]. Metall. Trans., 1977, 8B: 443
[20] Pak J J, Jeong Y S, Hong I K, et al.Thermodynamics of formation TiN in Fe-Cr melts[J]. ISIJ Int., 2005, 45: 1106
[21] Kunze J, Mickel C, Leonhardt M, et al.Precipitation of titanium nitride in low-alloyed steel during solidification[J], Steel Res., 1997, 68: 403
[22] Meng F J, Wang J Q, Han E H, et al.The role of TiN inclusions in stress corrosion crack initiation for Alloy 690TT in high-temperature and high-pressure water[J]. Corros. Sci., 2010, 52: 927
[23] Abdulranhan R F, Hendry A.The solubility of nitrogen in liquid pure nickel[J]. Metall. Mater. Trans., 2001, 32B: 1095
[24] Abdulranhan R F, Hendry A.Solubility of nitrogen in liquid nickel-based alloys[J]. Metall. Mater. Trans., 2001, 32B: 1103
[25] Simmons J W, Covino B S, Hawk J A.Effect of nitride (Cr2N) precipitation on the mechanical, corrosion, and wear properties of austenitic stainless steel[J]. ISIJ Int., 1996, 36: 846
[26] Mao W M, Zhu J C, Li J, et al.Structure and Properties of Metallic Materials [M]. Beijing: Tsinghua University Press, 2008: 127(毛卫明, 朱景川, 郦剑等. 金属材料结构与性能 [M]. 北京: 清华大学出版社, 2008: 127)
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