Study on Irradiation Assisted Stress Corrosion Cracking of Nuclear Grade 304 Stainless Steel

doi:10.11900/0412.1961.2018.00359

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	Study on Irradiation Assisted Stress Corrosion Cracking of Nuclear Grade 304 Stainless Steel
	Deng Ping 1,4; Sun Chen 2; Peng Qunjia 4,5; Han En-Hou 4; Ke Wei 4; Rao Zhijie 3
刊名	ACTA METALLURGICA SINICA
	2019-03-11
卷号	55 期号:3 页码:349-361
关键词	nuclear grade stainless steel proton irradiation localized deformation corrosion irradiation assisted stress corrosion cracking
ISSN号	0412-1961
DOI	10.11900/0412.1961.2018.00359
通讯作者	Peng Qunjia(pengqunjia@cgnpc.com.cn)
英文摘要	Irradiation assisted stress corrosion cracking (IASCC) of austenitic stainless steel core components is one major concern for maintenance of nuclear power plants. Previous studies on the IASCC had mainly focused on the effect of irradiation on changes in deformation modes and interaction of dislocation channels with grain boundary. The role of corrosion in IASCC, however, has not received sufficient attentions. In the process of stress corrosion cracking (SCC), corrosion occurs simultaneously with localized deformation in the vicinity of the crack tip. This indicates that corrosion is one of the potential contributors to IASCC. In this work, IASCC of proton-irradiated nuclear grade 304 stainless steel (304SS) was investigated. The IASCC tests were conducted by interrupted slow strain rate tensile (SSRT) tests at 320 degrees C in simulated primary water of pressurized water reactor containing 1200 mg/L B as H3BO3 and 2.3 mg/L Li as LiOH center dot H2O, with a dissolved hydrogen concentration of 2.6 mg/L. Following the SSRT tests, the localized deformation, corrosion and IASCC of the specimens were characterized. The results revealed that increasing the irradiation dose promoted residual strain accumulation at slip steps and grain boundaries of nuclear grade 304SS. Since the slip step usually transmitted or terminated at the grain boundary, it eventually promoted localized deformation at the grain boundary. Specially, the slip step transmitted at grain boundary led to slip continuity at the grain boundary. In contrast, a slip discontinuity was observed at the grain boundary where the slip step terminated, which caused a much higher strain accumulation by feeding dislocations to the grain boundary region. Further, formation of the slip discontinuity was related to the Schmidt factor pair type of the adjacent grains. The irradiation resulted in a depletion of Cr and an enrichment of Ni at grain boundary, while the magnitude of Cr depletion and Ni enrichment increased with increasing the irradiation dose. Following the SSRT tests, intergranular cracking was observed on surfaces of the irradiated specimens, while the number of the cracks was increased by a higher irradiation dose and applied strain. This suggested a higher IASCC susceptibility of nuclear grade 304SS in the primary water. Meanwhile, significant intergranular oxidation ahead of the crack tip was observed, while both the width and length of the oxide were larger at a higher irradiation dose. The synergic effect of irradiation-promoted deformation and intergranular corrosion was the primary cause for the IASCC of the irradiated steel.
WOS研究方向	Metallurgy & Metallurgical Engineering
语种	英语
出版者	SCIENCE PRESS
WOS记录号	WOS:000457467900007
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/131689]
专题	金属研究所_中国科学院金属研究所
通讯作者	Peng Qunjia
作者单位	1.Univ Sci & Technol China, Sch Mat Sci & Engn, Shenyang 110016, Liaoning, Peoples R China 2.State Power Investment Corp, Res Inst, Beijing 102209, Peoples R China 3.Univ Michigan, Dept Nucl Engn & Radiol Sci, Ann Arbor, MI 48109 USA 4.Chinese Acad Sci, Inst Met Res, CAS Key Lab Nucl Mat & Safety Assessment, Shenyang 110016, Liaoning, Peoples R China 5.Suzhou Nucl Power Res Inst, Suzhou 215004, Peoples R China
推荐引用方式 GB/T 7714	Deng Ping,Sun Chen,Peng Qunjia,et al. Study on Irradiation Assisted Stress Corrosion Cracking of Nuclear Grade 304 Stainless Steel[J]. ACTA METALLURGICA SINICA,2019,55(3):349-361.
APA	Deng Ping,Sun Chen,Peng Qunjia,Han En-Hou,Ke Wei,&Rao Zhijie.(2019).Study on Irradiation Assisted Stress Corrosion Cracking of Nuclear Grade 304 Stainless Steel.ACTA METALLURGICA SINICA,55(3),349-361.
MLA	Deng Ping,et al."Study on Irradiation Assisted Stress Corrosion Cracking of Nuclear Grade 304 Stainless Steel".ACTA METALLURGICA SINICA 55.3(2019):349-361.