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Acta Metall Sin  2022, Vol. 58 Issue (7): 883-894    DOI: 10.11900/0412.1961.2020.00533
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Microstructure Evolution at Elevated Temperature and Mechanical Properties of MoNb-Modified FeCrAl Stainless Steel
WEN Donghui1, JIANG Beibei2, WANG Qing3(), LI Xiangwei1, ZHANG Peng1, ZHANG Shuyan1()
1.Centre of Excellence for Advanced Materials, Dongguan 523808, China
2.Analysis and Test Center, Guangdong University of Technology, Guangzhou 510006, China
3.School of Materials Science and Engineering, Dalian University of Technology, Dalian 116024, China
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WEN Donghui, JIANG Beibei, WANG Qing, LI Xiangwei, ZHANG Peng, ZHANG Shuyan. Microstructure Evolution at Elevated Temperature and Mechanical Properties of MoNb-Modified FeCrAl Stainless Steel. Acta Metall Sin, 2022, 58(7): 883-894.

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MoNb-modified FeCrAl ferritic stainless steel (C35MN: Fe-13Cr-4.5Al-2Mo-1Nb, mass fraction, %) exhibits excellent comprehensive properties, including oxidation and corrosion resistance, as well as moderate mechanical properties, machinability, and neutron irradiation-resistance, making them potential accident-tolerant fuel (ATF) cladding materials for pressurized water reactors. However, the microstructural evolution and corresponding mechanical properties of C35MN alloys at the loss-of-coolant accident temperature have not been systematically studied. Herein, the microstructural evolution and mechanical properties of C35MN alloys during 400 h aging at 800oC and 1 h annealing at 1000-1200oC were systematically investigated. The alloy ingots were prepared by vacuum induction melting and cast into round bars, followed by 1150oC hot-forging, 800oC hot-rolling, and aging at 800oC for 400 h. The samples annealed at 1000-1200oC for 1 h were preaged at 800oC for 24 h. The C35MN alloy exhibited excellent microstructural stability at 800 and 1000oC, which is attributed to the precipitation of the Laves phase. The alloy showed a good combination of strength and ductility. However, when the annealing temperature increased above 1100oC, a large amount of the Laves phase dissolved into the ferritic matrix, resulting in the coarsening of the matrix grains. Annealing above 1200oC for 1 h, the grain size increased to 310 μm, severely degrading the mechanical property of the C35MN alloy below the requirement of ATF cladding materials. The microstructural stability of the C35MN alloy was influenced by the thermal stability of the Laves phase, which depends on the composition of the phase. The thermal stability of the Laves phase depends on the solid solubility of Laves phase forming elements in the ferritic matrix: the lower the solid solubility, the higher thermal stability of the Laves phase. The mechanical properties of C35MN were significantly affected by the grain size. The alloy exhibited ductile fracture when the grain size was less than 50 μm and brittle cleavage fracture when the grain size was above 130 μm.

Key words:  fuel cladding material      FeCrAl stainless steel      microstructural stability      Laves phase      mechanical property     
Received:  30 December 2020     
ZTFLH:  TG113.1  
Fund: Guangdong Basic and Applied Basic Research Foundation(2019A1515110051);Guangdong Innovative and Entrepreneurial Research Team Program(2016ZT06G025)

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Table 1  Nominal and measured compositions of Fe-13Cr-4.5Al-2Mo-1Nb (C35MN) alloy
Fig.1  OM (a) and SEM (b) images of the 800oC, 24 h aged C35MN alloy
Fig.2  XRD spectra of C35MN alloy with different heat-treatments
Fig.3  SEM images of the C35MN alloy aged at 800oC for 2 h (a), 8 h (b), 50 h (c), 100 h (d), 200 h (e), 300 h (f), and 400 h (g), and the corresponding variation curves of the volume fraction and precipitate size of Laves phase (h)
Fig.4  OM images of the C35MN alloy aged at 800oC for 2 h (a) and 400 h (b)
Fig.5  OM (a, c, e) and SEM (b, d, f) images of the C35MN alloy annealed at 1000oC, 1 h (a, b), 1100oC, 1 h (c, d), and 1200oC, 1 h (e, f) after 800oC, 24 h aging
Fig.6  Variation of the volume fraction of Laves phase and grain size of C35MN alloy with annealed temperature
Fig.7  TEM bright-field images (a-c) and SAED pattern (inset) of the C35MN alloy annealed at 1000oC, 1 h after 800oC, 24 h aging
Fig.8  Engineering tensile stress-strain curves of the 800oC, 24 h aged C35MN alloy at different temperatures (RT—room tmperature) (a), and variation of mechanical properties with temperature (b)
Fig.9  SEM fracture images (a, b) and BSE-SEM images showing the deformed microstructure (c, d) at RT (a-c) and 800oC (d) of the 800oC, 24 h aged C35MN alloy near fracture surface
Fig.10  Engineering tensile stress-strain curves of the annealed and annealed + 800oC, 24 h re-aged C35MN alloy after 800oC, 24 h aging (a), and variation of mechanical property parameters with heat treatment states (b)
Fig.11  Variation of the micro-hardness of C35MN alloy with aging time at 800oC, the hardness of annealed alloys at different temperature also exhibited



CompositionSolid solubility[29]
Table 2  Compositions of Laves phase and the solid solubilities of Mo and Nb elements in ferrite in C35MN alloy
Fig.12  SEM fracture images of the annealed and annealed + 800oC, 24 h re-aging alloys after 800oC, 24 h aging
(a) 1000oC, 1 h (b) 1000oC, 1 h + 800oC, 24 h
(c) 1100oC, 1 h (d) 1100oC, 1 h + 800oC, 24 h
(e) 1200oC, 1 h (f) 1200oC, 1 h + 800oC, 24 h
1 Hallstadius L, Johnson S, Lahoda E. Cladding for high performance fuel [J]. Prog. Nucl. Energy, 2012, 57: 71
doi: 10.1016/j.pnucene.2011.10.008
2 Rebak R B. Advanced steels for accident tolerant fuel cladding in current light water reactors [A]. Energy Materials 2014 [C]. New York: Springer, 2014: 433
3 Baba M. Fukushima accident: What happened? [J]. Radiat. Meas., 2013, 55: 17
doi: 10.1016/j.radmeas.2013.01.013
4 Zinkle S J, Terrani K A, Gehin J C, et al. Accident tolerant fuels for LWRs: A perspective [J]. J. Nucl. Mater., 2014, 448: 374
doi: 10.1016/j.jnucmat.2013.12.005
5 Bragg-Sitton S. Development of advanced accident-tolerant fuels for commercial LWRs [J]. Nucl. News, 2014, 57: 83
6 Robb K R. Analysis of the FeCrAl accident tolerant fuel concept benefits during BWR station blackout accidents [A]. 16th International Topical Meeting on Nuclear Reactor Thermal Hydraulics [C]. Chicago, IL, USA: Oak Ridge National Lab. (ORNL), 2015: 1183
7 Zinkle S J, Was G S. Materials challenges in nuclear energy [J]. Acta Mater., 2013, 61: 735
doi: 10.1016/j.actamat.2012.11.004
8 Kaneda J, Kasahara S, Kuniya J, et al. General corrosion properties of titanium based alloys for the fuel claddings in the supercritical water-cooled reactor [A]. Proceedings of the 12th International Conference on Environmental Degradation of Materials in Nuclear Power Systems: Water Reactors [C]. Salt Lake City, UT: The Minerals, Metals & Materials Society, 2005: 1409
9 Opila E J. Volatility of common protective oxides in high-temperature water vapor: Current understanding and unanswered questions [J]. Mater. Sci. Forum, 2004, 461-464: 765
doi: 10.4028/
10 Cheng T, Keiser J R, Brady M P, et al. Oxidation of fuel cladding candidate materials in steam environments at high temperature and pressure [J]. J. Nucl. Mater., 2012, 427: 396
doi: 10.1016/j.jnucmat.2012.05.007
11 Liu J K, Zhang X H, Yun D. A complete review and a prospect on the candidate materials for accident tolerant fuel claddings [J]. Mater. Rev., 2018, 32A: 1757
刘俊凯, 张新虎, 恽 迪. 事故容错燃料包壳候选材料的研究现状及展望 [J]. 材料导报, 2018, 32A: 1757
12 Terrani K A, Zinkle S J, Snead L L. Advanced oxidation-resistant iron-based alloys for LWR fuel cladding [J]. J. Nucl. Mater., 2014, 448: 420
doi: 10.1016/j.jnucmat.2013.06.041
13 Wu X, Kozlowski T, Hales J D. Neutronics and fuel performance evaluation of accident tolerant FeCrAl cladding under normal operation conditions [J]. Ann. Nucl. Energy, 2015, 85: 763
doi: 10.1016/j.anucene.2015.06.032
14 Rebak R B. Alloy selection for accident tolerant fuel cladding in commercial light water reactors [J]. Metall. Mater. Trans., 2015, 2E: 197
15 Field K G, Snead M A, Yamamoto Y, et al. Handbook on the material properties of FeCrAl alloys for nuclear power production applications (FY18 Version: Revision 1) [R]. Oak Ridge, TN (United States): Oak Ridge National Lab. (ORNL), 2018
16 Unocic K A, Yamamoto Y, Pint B A. Effect of Al and Cr content on air and steam oxidation of FeCrAl alloys and commercial APMT alloy [J]. Oxid. Met., 2017, 87: 431
doi: 10.1007/s11085-017-9745-1
17 Ejenstam J, Thuvander M, Olsson P, et al. Microstructural stability of Fe-Cr-Al alloys at 450-550oC [J]. J. Nucl. Mater., 2015, 457: 291
doi: 10.1016/j.jnucmat.2014.11.101
18 Capdevila C, Miller M K, Chao J. Phase separation kinetics in a Fe-Cr-Al alloy [J]. Acta Mater., 2012, 60: 4673
doi: 10.1016/j.actamat.2012.05.022
19 Edmondson P D, Briggs S A, Yamamoto Y, et al. Irradiation-enhanced α' precipitation in model FeCrAl alloys [J]. Scr. Mater., 2016, 116: 112
doi: 10.1016/j.scriptamat.2016.02.002
20 Gao S X, Li W J, Chen P, et al. Study on irradiation behavior of fuel rods with FeCrAl cladding [J]. Nucl. Power Eng., 2017, 38(5): 175
高士鑫, 李文杰, 陈 平 等. FeCrAl 包壳燃料棒辐照行为研究 [J]. 核动力工程, 2017, 38(5): 175
21 Yamamoto Y, Gussev M N, Kim B, et al. Optimized properties on base metal and thin-walled tube of Generation II ATF FeCrAl [R]. Oak Ridge, TN (United States): Oak Ridge National Lab. (ORNL), 2015
22 Morachevskii A G. Professor Gustav Tammann (To 140th birthday anniversary) [J]. Russ. J. Appl. Chem., 2001, 74: 1610
doi: 10.1023/A:1017420113016
23 Motta A T, Yilmazbayhan A, da Silva M J G, et al. Zirconium alloys for supercritical water reactor applications: Challenges and possibilities [J]. J. Nucl. Mater., 2007, 371: 61
doi: 10.1016/j.jnucmat.2007.05.022
24 Yamamoto Y, Yang Y, Field K G, et al. Letter report documenting progress of second generation ATF FeCrAl alloy fabrication [R]. Oak Ridge, TN (United States): Oak Ridge National Lab. (ORNL), 2014
25 Sun Z Q, Bei H B, Yamamoto Y. Microstructural control of FeCrAl alloys using Mo and Nb additions [J]. Mater. Charact., 2017, 132: 126
doi: 10.1016/j.matchar.2017.08.008
26 Sun Z Q, Edmondson P D, Yamamoto Y. Effects of Laves phase particles on recovery and recrystallization behaviors of Nb-containing FeCrAl alloys [J]. Acta Mater., 2018, 144: 716
doi: 10.1016/j.actamat.2017.11.027
27 Niu B, Wang Z H, Wang Q, et al. Dual-phase synergetic precipitation in Nb/Ta/Zr Co-modified Fe-Cr-Al-Mo alloy [J]. Intermetallics, 2020, 124: 106848
doi: 10.1016/j.intermet.2020.106848
28 Zheng J Y, Jia Y Z, Du P N, et al. Control of Laves precipitation in a FeCrAl-based alloy through severe thermomechanical processing [J]. Materials, 2019, 12: 2939
doi: 10.3390/ma12182939
29 Tang R Z, Tian R Z. Binary Alloy Phase Diagrams and Crystal Structure of Intermediate Phase [M]. Changsha: Central South University, 2009: 535
唐仁政, 田荣璋. 二元合金相图及中间相晶体结构 [M]. 长沙: 中南大学出版社, 2009: 535
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