Austenite decomposition behavior adjacent to δ-ferrite in a Si-modified Fe-Cr-Ni austenitic stainless steel during thermal aging at 550 °C

doi:10.1016/j.actamat.2024.119948

IMR OpenIR

	Austenite decomposition behavior adjacent to δ-ferrite in a Si-modified Fe-Cr-Ni austenitic stainless steel during thermal aging at 550 °C
	Xie, Ang 1,2; Chen, Shenghu 1; Chen, Sihan 1; Jiang, Haichang 1; Rong, Lijian 1
通讯作者	Chen, Shenghu(chensh@imr.ac.cn) ; Rong, Lijian(ljrong@imr.ac.cn)
	2024-06-15
发表期刊	ACTA MATERIALIA
ISSN	1359-6454
卷号	272 页码:19
摘要	The delta-ferrite decomposition has been widely reported in conventional Fe-Cr-Ni austenitic stainless steel during thermal aging. However, a novel phenomenon is found in a Si-modified austenitic stainless steel, that delta-ferrite decomposition is suppressed, replaced by the decomposition of adjacent austenite. Herein, the decomposition behavior of austenite adjacent to delta-ferrite and its effect on impact toughness in a Si-modified austenitic stainless steel during aging at 550 degrees C up to 3000 h have been investigated. During thermal aging, austenite adjacent to delta-ferrite is decomposed in the following sequence: (1) gamma -> M23C6 + alpha transformation takes place. The preferential formation of secondary M23C6 carbides not only rejects Si atoms into the surrounding austenite but also produces a C-depleted zone. The transformation of austenite to ferrite is induced in the Si-riched and C-depleted microzone. (2) The growth of secondary M23C6 carbides induces a continuous rejection of Ni and Si atoms into M23C6/gamma and M23C6/alpha interfaces, and the strong attractive interaction between Ni and Si provides the chemical driving force for nucleation of M6C carbides and G-phase. (3) With prolonged aging time, the lower C, high Ni, and high Si concentrations in the frontier of decomposed austenite will promote the preferential precipitation of M6C carbides rather than M23C6 carbides. During impact deformation, microcracks caused by strain incompatibility between secondary M23C6 and alpha-ferrite, resulting in a slight decrease in impact toughness. As austenite decomposition proceeds, the higher strain incompatibility across M6C/alpha interfaces leads to brittle cleavage fracture, resulting in a significant decrease in impact toughness.
关键词	Si-modified austenitic stainless steel Thermal aging delta-ferrite Austenite decomposition Fracture behavior
资助者	China ; Youth Innovation Promotion Association, CAS ; LingChuang Research Project of China National Nuclear Corporation ; CNNC Science Fund for Talented Young Scholars
DOI	10.1016/j.actamat.2024.119948
收录类别	SCI
语种	英语
资助项目	China[U23B2074] ; China[51871218] ; Youth Innovation Promotion Association, CAS[2018227] ; LingChuang Research Project of China National Nuclear Corporation ; CNNC Science Fund for Talented Young Scholars
WOS研究方向	Materials Science ; Metallurgy & Metallurgical Engineering
WOS类目	Materials Science, Multidisciplinary ; Metallurgy & Metallurgical Engineering
WOS记录号	WOS:001235072800001
出版者	PERGAMON-ELSEVIER SCIENCE LTD
引用统计	被引频次：12[WOS] [WOS记录] [WOS相关记录]
文献类型	期刊论文
条目标识符	http://ir.imr.ac.cn/handle/321006/186711
专题	中国科学院金属研究所
通讯作者	Chen, Shenghu; Rong, Lijian
作者单位	1.Chinese Acad Sci, Inst Met Res, Key Lab Nucl Mat & Safety Assessment, Shenyang 110016, Peoples R China 2.Univ Sci & Technol China, Sch Mat Sci & Engn, Hefei 230026, Peoples R China
推荐引用方式 GB/T 7714	Xie, Ang,Chen, Shenghu,Chen, Sihan,et al. Austenite decomposition behavior adjacent to δ-ferrite in a Si-modified Fe-Cr-Ni austenitic stainless steel during thermal aging at 550 °C[J]. ACTA MATERIALIA,2024,272:19.
APA	Xie, Ang,Chen, Shenghu,Chen, Sihan,Jiang, Haichang,&Rong, Lijian.(2024).Austenite decomposition behavior adjacent to δ-ferrite in a Si-modified Fe-Cr-Ni austenitic stainless steel during thermal aging at 550 °C.ACTA MATERIALIA,272,19.
MLA	Xie, Ang,et al."Austenite decomposition behavior adjacent to δ-ferrite in a Si-modified Fe-Cr-Ni austenitic stainless steel during thermal aging at 550 °C".ACTA MATERIALIA 272(2024):19.