Investigation on freckle formation and evolution of single-crystal nickel-based superalloy specimens with different thicknesses and abrupt cross-section changes

doi:10.1016/j.jallcom.2019.07.045

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	Investigation on freckle formation and evolution of single-crystal nickel-based superalloy specimens with different thicknesses and abrupt cross-section changes
	Han, Dongyu 1,2; Jiang, Weiguo 2; Xiao, Jiuhan 1,2; Li, Kaiwen 2; Lu, Yuzhang 2; Zheng, Wei 2; Zhang, Shaohua 2; Lou, Langhong 2
刊名	JOURNAL OF ALLOYS AND COMPOUNDS
	2019-10-15
卷号	805 页码:218-228
关键词	Nickel-based superalloy Crystal growth Freckle Abruptly expanding cross-section
ISSN号	0925-8388
DOI	10.1016/j.jallcom.2019.07.045
通讯作者	Jiang, Weiguo(wgjiang@imr.ac.cn)
英文摘要	The freckle formation and evolution in directionally solidified single-crystal specimens with different thicknesses and abruptly expanding rectangular cross-section were investigated at different withdrawal rates. The microstructure was studied by optical microscope (OP) and scanning electron microscope (SEM), and the crystallographic orientation in freckle areas was characterized by electron backscattered diffraction (EBSD). The experimental results showed that the freckle was the most severe in specimens with a thickness of 10 mm at the same withdrawal rate, and the freckle chain was observed to form below an abruptly expanding cross-section ended at the expanding step. It was found that freckles formed exclusively on the edges of casting facing the central sprue of the shell mould. Findings reveal that freckles tend to form at the highest position of the mushy zone, mainly due to the thermosolutal convection and the radial flow caused by feeding behavior in the mushy zone. The freckle formation is pronounced at a low withdrawal rate, and can further generate stray grains. (C) 2019 Elsevier B.V. All rights reserved.
资助项目	National Natural Science Foundation of China[51674235] ; National Key Research and Development Program of China[2017YFB0702904]
WOS研究方向	Chemistry ; Materials Science ; Metallurgy & Metallurgical Engineering
语种	英语
出版者	ELSEVIER SCIENCE SA
WOS记录号	WOS:000482184100026
资助机构	National Natural Science Foundation of China ; National Key Research and Development Program of China
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/135169]
专题	金属研究所_中国科学院金属研究所
通讯作者	Jiang, Weiguo
作者单位	1.Univ Sci & Technol China, Sch Mat Sci & Engn, Shenyang 110016, Liaoning, Peoples R China 2.Chinese Acad Sci, Inst Met Res, Shenyang 110016, Liaoning, Peoples R China
推荐引用方式 GB/T 7714	Han, Dongyu,Jiang, Weiguo,Xiao, Jiuhan,et al. Investigation on freckle formation and evolution of single-crystal nickel-based superalloy specimens with different thicknesses and abrupt cross-section changes[J]. JOURNAL OF ALLOYS AND COMPOUNDS,2019,805:218-228.
APA	Han, Dongyu.,Jiang, Weiguo.,Xiao, Jiuhan.,Li, Kaiwen.,Lu, Yuzhang.,...&Lou, Langhong.(2019).Investigation on freckle formation and evolution of single-crystal nickel-based superalloy specimens with different thicknesses and abrupt cross-section changes.JOURNAL OF ALLOYS AND COMPOUNDS,805,218-228.
MLA	Han, Dongyu,et al."Investigation on freckle formation and evolution of single-crystal nickel-based superalloy specimens with different thicknesses and abrupt cross-section changes".JOURNAL OF ALLOYS AND COMPOUNDS 805(2019):218-228.