Characteristics, Mechanism and Criterion of Channel Segregation in NbTi Alloy via Numerical Simulations and Experimental Characterizations

doi:10.3390/ma14040796

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	Characteristics, Mechanism and Criterion of Channel Segregation in NbTi Alloy via Numerical Simulations and Experimental Characterizations
	Zhu, Baohui 1; Chen, Zhenzhen 2,3; Cao, Yanfei 3; Liu, Yanchang 1; Kang, Xiuhong 3; Chen, Yun 3; Liu, Hongwei 3; Fu, Paixian 3; Luan, Yikun 3; Li, Dianzhong 3
刊名	MATERIALS
	2021-02-01
卷号	14 期号:4 页码:17
关键词	NbTi alloy channel segregation simulations experimental characterizations criterion
DOI	10.3390/ma14040796
通讯作者	Cao, Yanfei(yfcao10s@imr.ac.cn) ; Li, Dianzhong(dzli@imr.ac.cn)
英文摘要	Channel segregation (CS) is the most typical defect during solidification of NbTi alloy. Based on numerical simulation and experimental characterizations, we deeply elucidated its characteristics, formation mechanism, effecting factor and prediction criterion. According to acid etching, industrial X-ray transmission imaging, 3D X-ray microtomography and chemical analysis, it was found that in a casing ingot, by He cooling, finer grain size, weaker segregation and slighter CS can be obtained compared with air-cooled ingot. The simulation results of macrosegregation show that CS is caused by the strong natural convection in the mushy zone triggered by the thermo-solutal gradient. Its formation can be divided into two stages including channel initiation and growth. In addition, due to the stronger cooling effect of the He treatment, the interdendritic flow velocity becomes smaller, consequently lowering the positive segregation and CS and improving the global homogenization of the final ingot. Finally, to predict the formation of CS, the Rayleigh number model was proposed and its critical value was found to be 15 in NbTi alloy for the first time. When it is lower than the threshold, CS disappears. It provides an effective tool to evaluate and optimize the solidification parameters to fabricate the homogenized NbTi ingot in engineering practice.
资助项目	National Natural Science Foundation of China[51701225] ; National Natural Science Foundation of China[U1708252] ; State Key Laboratory of Special Rare Metal Materials in Northwest Rare Metal Materials Research Institute Ningxia Co., Ltd.[SKL2017K002] ; CAS Light of West China[XAB2017AW10] ; Key Project of Ningxia Hui Autonomous Region Key Research and Development Program[2018BDE02022] ; National Science and Technology Major Project[2017-VII-0008-0101] ; Project to Strengthen Industrial Development at the Grass-roots Level[TC190A4DA/35] ; Young Talent Project by SYNL[L2019F33]
WOS研究方向	Chemistry ; Materials Science ; Metallurgy & Metallurgical Engineering ; Physics
语种	英语
出版者	MDPI
WOS记录号	WOS:000624089800001
资助机构	National Natural Science Foundation of China ; State Key Laboratory of Special Rare Metal Materials in Northwest Rare Metal Materials Research Institute Ningxia Co., Ltd. ; CAS Light of West China ; Key Project of Ningxia Hui Autonomous Region Key Research and Development Program ; National Science and Technology Major Project ; Project to Strengthen Industrial Development at the Grass-roots Level ; Young Talent Project by SYNL
内容类型	期刊论文
源URL	[http://ir.imr.ac.cn/handle/321006/160512]
专题	金属研究所_中国科学院金属研究所
通讯作者	Cao, Yanfei; Li, Dianzhong
作者单位	1.Northwest Rare Met Mat Res Inst Ningxia Co Ltd, State Key Lab Special Rare Met Mat, Shizuishan 753000, Peoples R China 2.Univ Sci & Technol China, Sch Mat Sci & Engn, Hefei 230026, Peoples R China 3.Chinese Acad Sci, Shenyang Natl Lab Mat Sci, Inst Met Res, Shenyang 110016, Peoples R China
推荐引用方式 GB/T 7714	Zhu, Baohui,Chen, Zhenzhen,Cao, Yanfei,et al. Characteristics, Mechanism and Criterion of Channel Segregation in NbTi Alloy via Numerical Simulations and Experimental Characterizations[J]. MATERIALS,2021,14(4):17.
APA	Zhu, Baohui.,Chen, Zhenzhen.,Cao, Yanfei.,Liu, Yanchang.,Kang, Xiuhong.,...&Li, Dianzhong.(2021).Characteristics, Mechanism and Criterion of Channel Segregation in NbTi Alloy via Numerical Simulations and Experimental Characterizations.MATERIALS,14(4),17.
MLA	Zhu, Baohui,et al."Characteristics, Mechanism and Criterion of Channel Segregation in NbTi Alloy via Numerical Simulations and Experimental Characterizations".MATERIALS 14.4(2021):17.