An insight into oversaturated deformation-induced sigma precipitation in Super304H austenitic stainless steel
作者:Zhou, QW (Zhou, Qingwen)[ 1 ] ; Liu, JW (Liu, Jiangwen)[ 1,2 ] ; Gao, Y (Gao, Yan)[ 1,2 ]
MATERIALS & DESIGN
卷: 181
文献号: UNSP 108056
DOI: 10.1016/j.matdes.2019.108056
出版年: NOV 5 2019
文献类型:Article
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摘要
A new mechanism of the deformation-promoted precipitation of the sigma phase during aging at 650 degrees C in nanocrystallized Super304H austenitic stainless steel was proposed for its extremely early nucleation and subsequently fast growth. Unlike the reports of sigma phase nucleation at the recrystallizing grain boundaries in other deformed steels, the sigma phase was found to nucleate before recrystallization during aging in the oversaturated shot-peened Super304H steel at stress concentrations with high distortion energy (nanograin boundaries, twinning intersections and interfaces of dispersion strengthening phases like Nb(C,N)). The high-distortion areas favored the segregation of chromium and consequently facilitated the structure transformation from face-centered cubic austenite to topologically close-packed sigma phase. Sigma phase particles were found to grow slowly in the early stage of aging due to the residual compressive stress field in the deformed austenite matrix, and began to grow abnormally quickly to be 1-2 mu m in size at the recrystallizing boundaries when recrystallization commences, due to both the release of residual compressive stress at the recrystallized region and the fast chromium diffusion at the deformed nanostructure region. To avoid the occurrence of sigma phases, the degree of surface deformation should be controlled to be lower than the deformation saturation value. (C) 2019 The Authors. Published by Elsevier Ltd.
关键词
作者关键词:Austenitic stainless steel; Nanocrystalline; Sigma phase; Nucleation; Recrystallization
KeyWords Plus:COMPRESSIVE RESIDUAL-STRESS; PHASE PRECIPITATION; BOILER MATERIALS; BEHAVIOR; MICROSTRUCTURE; SURFACE; CRYSTALLOGRAPHY; SENSITIZATION; RESISTANCE; STABILITY
作者信息
通讯作者地址: Gao, Y (通讯作者)
显示更多South China Univ Technol, Sch Mat Sci & Engn, Guangzhou 510641, Guangdong, Peoples R China.
地址:
显示更多[ 1 ] South China Univ Technol, Sch Mat Sci & Engn, Guangzhou 510641, Guangdong, Peoples R China
[ 2 ] Key Lab Adv Energy Storage Mat Guangdong Prov, Guangzhou, Guangdong, Peoples R China
电子邮件地址:meygao@scut.edu.cn
基金资助致谢
基金资助机构显示详情授权号
National Natural Science Foundation of China
51471072
Key Laboratory of Advanced Energy Storage Materials of Guangdong Province
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出版商
ELSEVIER SCI LTD, THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND
期刊信息
Impact Factor (影响因子): Journal Citation Reports
类别 / 分类
研究方向:Materials Science
Web of Science 类别:Materials Science, Multidisciplinary