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Acta Metall Sin  2020, Vol. 56 Issue (8): 1075-1083    DOI: 10.11900/0412.1961.2019.00445
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Effect of Ageing Treatment at 650 ℃ on Microstructure and Properties of 9Cr-ODS Steel
PENG Yanyan, YU Liming(), LIU Yongchang, MA Zongqing, LIU Chenxi, LI Chong, LI Huijun
Tianjin Key Lab of Composite and Functional Materials, School of Materials Science and Engineering, Tianjin University, Tianjin 300072, China
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Oxide dispersion strengthened (ODS) steel has excellent high-temperature performance and corrosion resistance. It has broad application prospect and development space in the key field of high temperature structural materials for nuclear power. 9Cr-ODS steel has become one of the most promising candidate materials in advanced nuclear reactors because of its excellent high temperature mechanical properties and radiation resistance. In this work, 9Cr-ODS steel was designed and prepared by powder metallurgy process. The as-hot isostatically pressed (HIPed) microstructure of the steel was studied and analyzed, including matrix grain distribution characteristics, micron-scale large size precipitated phase, and nanoscale oxide particles. In addition, the high temperature microstructure thermal stability of 9Cr-ODS steel aged at 650 ℃ for different time was researched by means of XRD, SEM, TEM and hardness test, and the microstructure change of matrix and hardness properties were analyzed. Based on the contrast analysis of the matrix microstructure and hardness properties, the hardness change of the austenitic ODS steel at high temperature was obtained. The results showed that the original as-HIPed microstructure of 9Cr-ODS steel is mainly composed of martensite lath and large amount of Y2O3. During ageing process, the lath martensite of 9Cr-ODS steel gradually coarsens and the number of dislocations decreases with ageing time increasing, and the Cr23C6 carbides begin to precipitate along the grain boundary and grow up. At the same time, the Laves phases with large size begin to precipitate in ageing and then grow with the increase of ageing time. Meanwhile, ageing treatment makes Y2O3 phase with larger size further grow, while Y2O3 phase with smaller size precipitate increase. This phenomenon can probably be associated with the dissolution of the fine particles induced from the particle coarsening, generally called the Ostwald-Ripening mechanism. The change of microhardness during ageing was related to the size of lath martensite and the number and density of the second phase precipitation, especially Cr23C6. The hardness test results show that the microhardness first decreases and then tends to be stable with the increase of ageing time.

Key words:  9Cr-ODS steel      ageing      thermal stability     
Received:  24 December 2019     
ZTFLH:  TG142.1  
Fund: National Natural Science Foundation of China(51974199);National Natural Science Foundation of China(U1960204)
Corresponding Authors:  YU Liming     E-mail:

Cite this article: 

PENG Yanyan, YU Liming, LIU Yongchang, MA Zongqing, LIU Chenxi, LI Chong, LI Huijun. Effect of Ageing Treatment at 650 ℃ on Microstructure and Properties of 9Cr-ODS Steel. Acta Metall Sin, 2020, 56(8): 1075-1083.

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Fig.1  XRD spectra of 9Cr-ODS steel under different ageing time at 650 ℃
Fig.2  TEM bright-field images of 9Cr-ODS steel with different ageing time at 650 ℃
(a) 0 h (b) 200 h (c) 500 h (d) 1000 h (e) 2000 h (f) 4000 h
Fig.3  Statistical histogram of martensite laths size (a) and average size of laths (b) in 9Cr-ODS steel with different ageing time at 650 ℃
Fig.4  TEM Bright-field images of oxides with different ageing time at 650 ℃
(a) 0 h (b) 200 h (c) 500 h (d) 1000 h (e) 2000 h (f) 4000 h
Fig.5  TEM image (a) and EDS (b) of oxides in 9Cr-ODS steel (Inset shows the SAED pattern of oxides)
Fig.6  SAED pattern of matrix and Y2O3
Fig.7  Statistical histogram (a) and average size (b) of Y2O3 in 9Cr-ODS steel with different ageing time at 650 ℃
Fig.8  TEM bright-field images of carbides in 9Cr-ODS steel with different ageing time at 650 ℃
(a) 0 h (b) 200 h (c) 500 h (d) 1000 h (e) 2000 h (f) 4000 h
Fig.9  TEM image (a) and EDS (b) of carbides in 9Cr-ODS steel (Inset shows the SAED pattern of carbides)
Fig.10  TEM bright-field images of Lavesphases in 9Cr-ODS steel with different ageing time at 650 ℃
(a) 50 h (b) 200 h (c) 500 h (d) 1000 h (e) 2000 h
Fig.11  TEM image (a) and EDS (b) of Laves phases in 9Cr-ODS steel (Inset shows the SAED pattern of Laves phases)
Fig.12  Vickers hardness change of 9Cr-ODS steel during ageing at 650 ℃
[1] Abram T, Ion S. Generation-IV nuclear power: A review of the state of the science [J]. Energy Policy, 2008, 36: 4323
doi: 10.1016/j.enpol.2008.09.059
[2] Mansur L K, Rowcliffe A F, Nanstad P K, et al. Materials needs for fusion, Generation IV fission reactors and spallation neutron sources-similarities and differences [J]. J. Nucl. Mater., 2004, 329-333: 166
doi: 10.1016/j.jnucmat.2004.04.016
[3] Xu M. The development of fast reactor technology, to ensure the sustainable development of nuclear energy [J]. China Nucl. Power, 2012, 5: 98
(徐 銤. 发展快堆技术, 保证核能可持续发展 [J]. 中国核电, 2012, 5: 98)
[4] Bloom E E, Busby J T, Duty C E, et al. Critical questions in materials science and engineering for successful development of fusion power [J]. J. Nucl. Mater., 2007, 367-370: 1
doi: 10.1016/j.jnucmat.2007.02.007
[5] Marques J G. Evolution of nuclear fission reactors: Third generation and beyond [J]. Energy Conv. Manag., 2010, 51: 1774
doi: 10.1016/j.enconman.2009.12.043
[6] Zhang Z, Chen D L. Consideration of Orowan strengthening effect in particulate-reinforced metal matrix nanocomposites: A model for predicting their yield strength [J]. Scr. Mater., 2006, 54: 1321
doi: 10.1016/j.scriptamat.2005.12.017
[7] Jiang Y, Smith J R, Odette G R. Formation of Y-Ti-O nanoclusters in nanostructured ferritic alloys: A first-principles study [J]. Phys. Rev., 2009, 79B: 064103
[8] Hirata A, Fujita T, Wen Y R, et al. Atomic structure of nanoclusters in oxide-dispersion-strengthened steels [J]. Nat. Mater., 2011, 10: 922
doi: 10.1038/nmat3150 pmid: 22019943
[9] Zhao Q, Yu L M, Liu Y C, et al. Microstructure and tensile properties of a 14Cr ODS ferritic steel [J]. Mater. Sci. Eng., 2017, A680: 347
[10] Ijiri Y, Oono N, Ukai S, et al. Oxide particle-dislocation interaction in 9Cr-ODS steel [J]. Nucl. Mater. Energy, 2016, 9: 378
[11] Zhang L, Ukai S, Hoshino T, et al. Y2O3 evolution and dispersion refinement in Co-base ODS alloys [J]. Acta Mater., 2009, 57: 3671
doi: 10.1016/j.actamat.2009.04.033
[12] Peng Y Y, Yu L M, Liu Y C, et al. Microstructures and tensile properties of an austenitic ODS heat resistance steel [J]. Mater. Sci. Eng., 2019, A767: 138419
[13] Peng Y Y. Study on precipitation behavior of strengthening phase and microstructure thermal stability of austenitic ODS steel [D]. Tianjin: Tianjin University, 2019
(彭艳艳. 奥氏体ODS钢的强化相析出行为及其组织热稳定性研究 [D]. 天津: 天津大学, 2019)
[14] Ren J, Yu L M, Liu Y C, et al. Effects of Zr addition on strengthening mechanisms of Al-alloyed high-Cr ODS steels [J]. Materials, 2018, 11: 118
doi: 10.3390/ma11010118
[15] Dong H Q, Yu L M, Liu Y C, et al. Effect of hafnium addition on the microstructure and tensile properties of aluminum added high-Cr ODS steels [J]. J. Alloys Compd., 2017, 702: 538
doi: 10.1016/j.jallcom.2017.01.298
[16] Muroga T, Nagasaka T, Li Y, et al. Fabrication and characterization of reference 9Cr and 12Cr-ODS low activation ferritic/martensitic steels [J]. Fusion Eng. Des., 2014, 89: 1717
doi: 10.1016/j.fusengdes.2014.01.010
[17] Li Y F, Abe H, Li F, et al. Grain structural characterization of 9Cr-ODS steel aged at 973 K up to 10,000 h by electron backscatter diffraction [J]. J. Nucl. Mater., 2014, 455: 568
doi: 10.1016/j.jnucmat.2014.08.047
[18] Yan P Y, Yu L M, Liu Y C, et al. Effects of Hf addition on the thermal stability of 16Cr-ODS steels at elevated aging temperatures [J]. J. Alloys Compd., 2018, 739: 368
doi: 10.1016/j.jallcom.2017.12.245
[19] Li Y F, Nagasaka T, Muroga T, et al. High-temperature mechanical properties and microstructure of 9Cr oxide dispersion strengthened steel compared with RAFMs [J]. Fusion Eng. Des., 2011, 86: 2495
doi: 10.1016/j.fusengdes.2011.03.004
[20] Zhou X S, Liu Y C, Yu L M, et al. Microstructure characteristic and mechanical property of transformable 9Cr-ODS steel fabricated by spark plasma sintering [J]. Mater. Des., 2017, 132: 158
doi: 10.1016/j.matdes.2017.06.063
[21] Yamamoto M, Ukai S, Hayashi S, et al. Formation of residual ferrite in 9Cr-ODS ferritic steels [J]. Mater. Sci. Eng., 2010, A527: 4418
[22] Ohtsuka S, Ukai S, Fujiwara M. Nano-mesoscopic structural control in 9Cr ODS ferritic/martensitic steels [J]. J. Nucl. Mater., 2006, 351: 241
doi: 10.1016/j.jnucmat.2006.02.006
[23] Zhang G M. Study on strengthening mechanism and performance evaluation of 9Cr oxide dispersion strengthened steel [D]. Beijing: University of Science and Technology Beijing, 2016
(张广明. 9Cr氧化物弥散强化的强化机理研究及性能评价 [D]. 北京: 北京科技大学, 2016)
[24] Dong H Q, Yu L M, Liu Y C, et al. Enhancement of tensile properties due to microstructure optimization in ODS steels by zirconium addition [J]. Fusion Eng. Des., 2017, 125: 402
doi: 10.1016/j.fusengdes.2017.03.170
[25] Abe F. Precipitate design for creep strengthening of 9% Cr tempered martensitic steel for ultra-supercritical power plants [J]. Sci. Technol. Adv. Mater., 2008, 9: 013002
doi: 10.1088/1468-6996/9/1/013002 pmid: 27877920
[26] Mukhopadhyay D K. Development of oxide dispersion strengthened ferritic steels for fusion [J]. J. Nucl. Mater., 1998, 258-263: 1209
doi: 10.1016/S0022-3115(98)00188-3
[27] Zhang L Y, Yu L M, Liu Y C, et al., Influence of Zr addition on the microstructures and mechanical properties of 14Cr ODS steels [J], Mater. Sci. Eng., 2017, A695:66
[28] Bentley J, Hoelzer D T, Coffey D W, et al. EFTEM and spectrum imaging of mechanically alloyed oxide-dispersion-strengthened 12YWT and 14YWT ferritic steels [J]. Microsc. Microanal., 2004, 10(S02): 662
[29] Sugino Y, Ukai S, Hayashi Q, et al. Directional recrystallization of ODS alloys by means of zone annealing [J]. J. Nucl. Mater., 2011, 417: 171
doi: 10.1016/j.jnucmat.2011.01.062
[30] Ren J, Yu L M, Liu Y C, et al., Microstructure evolution and tensile properties of an Al added high-Cr ODS steel during thermal aging at 650 ℃ [J]. Fusion Eng. Des., 2020, 157: 111700
doi: 10.1016/j.fusengdes.2020.111700
[31] Miller M K, Hoelzer D T, Kenik E A, et al. Stability of ferritic MA/ODS alloys at high temperatures [J]. Intermetallics, 2015, 13: 387
doi: 10.1016/j.intermet.2004.07.036
[32] Huang J D,Mei J P,Yan J L. Microstructure degradation and properties evolution of T91 steel during aging[J]. Heat Treat. Met., 2016, 42(11): 45
(黄金督, 梅建平, 晏井利等. T91钢时效过程中的组织老化和性能变化[J]. 金属热处理, 2016, 41(11): 45)
[33] Ren J, Yu L M, Liu Y C, et al., Corrosion behavior of an Al added high-Cr ODS steel in supercritical water at 600 ℃ [J]. Appl. Sur. Sci., 2019, 480: 969
doi: 10.1016/j.apsusc.2019.03.019
[34] Xie R, Lü Z, Lu C Y, et al. Characterization of nanosized precipitates in 9Cr-ODS steels by SAXS and TEM [J]. Acta Metall. Sin., 2016, 52: 1053
doi: 10.11900/0412.1961.2016.00164
(谢 锐, 吕 铮, 卢晨阳等. 9Cr-ODS钢中纳米析出相的SAXS和TEM研究 [J]. 金属学报, 2016, 52: 1053)
doi: 10.11900/0412.1961.2016.00164
[35] Shigeharu U, Takeji K, Satoshi O. Production and properties of nano-scale oxide dispersion strengthened (ODS) 9Cr martensitic steel claddings [J]. ISIJ Int., 2003, 43: 2038
doi: 10.2355/isijinternational.43.2038
[36] He J C, Wan F R. The research of nano-scale particles in the oxide dispersion strengthened steels [J]. J. Funct. Mater., 2014, 45: 17029
(贺建超, 万发荣. ODS钢中纳米氧化物颗粒成分与结构研究 [J]. 功能材料, 2014, 45: 17029)
[37] Zhang C H, Kimura A, Kasada R, et al. Characterization of the oxide particles in Al-added high-Cr ODS ferritic steels [J]. J. Nucl. Mater., 2011, 417: 221
doi: 10.1016/j.jnucmat.2010.12.063
[38] Li B, Xu X W. Microstructure and mechanical properties of aged T/P92 steel [J]. Heat Treat. Met., 2014, 39(12): 110
doi: 10.13251/j.issn.0254-6051.2014.12.029
(李 斌, 徐晓伟. T/P92钢的时效组织与性能 [J]. 金属热处理, 2014, 39(12): 110)
doi: 10.13251/j.issn.0254-6051.2014.12.029
[39] Ma W J, Lu Q, Shi Q Q, et al. Structure stability of a newly designed martensitic heat-resistant steel [J]. Heat Treat. Met., 2017, 42(5): 27
(马文杰, 卢 奇, 石全强等. 新设计的马氏体耐热钢的组织稳定性 [J]. 金属热处理, 2017, 42(5): 27)
[40] Hu P, Yan W, Shan Y Y, et al. Study on structural evolution and mechanical properties of high Cr ferritic heat-resistant steel in ageing process [J]. Guangdong Electr. Power, 2011, 24(11): 6
(胡 平, 严 伟, 单以银等. 高Cr铁素体耐热钢时效过程中的组织演变与力学性能研究 [J]. 广东电力, 2011, 24(11): 6)
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[1] . [J]. Acta Metall Sin, 2003, 39(8): 892 -896 .
[2] . [J]. Acta Metall Sin, 1999, 35(10): 1062 -1064 .
[3] . [J]. Acta Metall Sin, 1999, 35(6): 611 -617 .
[5] FENG Chun. The lower bainitic carbides are precipitated from austenite[J]. Acta Metall Sin, 2007, 43(6): 583 -588 .
[6] WANG Qiang MA Mingzhen ZHANG Xinyu LIU Riping. CRYSTAL GROWTH VELOCITY IN UNDERCOOLED Zr50Cu50 ALLOY MELT[J]. Acta Metall Sin, 2008, 44(12): 1415 -1418 .
[7] D.L.Li.(Department of Materials Physics; University of Science and Technology Beijing; Beijing100083; China)H.Hashimoto(Department of Mechanical Engineering; Okayama University of Science; Japan). Al_2Ni_3 PRECIPITATION INDUCED BY ELECTRON BEAM IRRADIATION[J]. Acta Metall Sin, 1997, 33(2): 213 -221 .
[8] LI Jiabao;KANG Zengqiao;HE Jiawen National Laboratory for Fatigue and Fracture of Materials; Institute of Metal Research; Academia Sinica; Shenyang; Xi'an Jiaotong University Correspondent; associate professor; Institute of Metal Research; Academia Sinica; Shenyang 110015. A METHOD FOR CORRECTING INTENSITY IN CONTINUOUS SCANNING X-RAY STRESS MEASUREMENT[J]. Acta Metall Sin, 1992, 28(5): 79 -84 .
[9] HE Jinrui;LU Younian;WANG Qingsui;SU Hansheng;ZHANG Xueduo;WU Mingchang;ZHU Qiao Beijing Institute of Aeronautical Materials P. O. No. 81-23;Beiing 100095. TIME-DEPENDENT FATIGUE AND ITS MICROMECHANISM OF SUPERALLOY GH169 UNDER OXIDATION[J]. Acta Metall Sin, 1990, 26(2): 64 -68 .
[10] XIE Xishan DONG Jianxin FU Shuhong ZHANG Maicang. RESEARCH AND DEVELOPMENT OF γ´´ AND γ´ STRENGTHENED Ni-Fe BASE SUPERALLOY GH4169[J]. Acta Metall Sin, 2010, 46(11): 1289 -1302 .