Formation Mechanisms of Hot Cracks in Laser Additive Repairing Single Crystal Superalloys

doi:10.11900/0412.1961.2023.00147

IMR OpenIR

	Formation Mechanisms of Hot Cracks in Laser Additive Repairing Single Crystal Superalloys
	Lu, Nannan 1; Guo, Yimo 1,2; Yang, Shulin 3; Liang, Jingjing 1; Zhou, Yizhou 1; Sun, Xiaofeng 1; Li, Jinguo 1
通讯作者	Li, Jinguo(jgli@imr.ac.cn)
	2023-09-11
发表期刊	ACTA METALLURGICA SINICA
ISSN	0412-1961
卷号	59 期号:9 页码:1243-1252
摘要	Hot cracking is a prevalent defect in metallurgy that often occurs during the laser additive repair of single crystal superalloys. The understanding of the cracking mechanism is vital for defect prevention. Consequently, this study entails combining experimental analysis and theoretical calculations to investigate the hot cracking mechanism in a second-generation single crystal superalloy, DD432, during laser additive repairing. The incident of hot cracking was observed predominantly at high-angle grain boundaries (HAGBs). High-magnitude stress concentrations were identified on both sides of the crack, accompanied by an extensive distribution of MC-type carbides in the crack initiation region. Hot cracking depended on factors such as liquid film stability, stress concentration, and MC-type carbide precipitates. The stability of the liquid film depended on dendrite coalescence undercooling, which in turn was related to the angle of grain boundaries. According to Rappaz's theory of dendrite coalescence undercooling, the calculated dendrite coalescence undercooling at HAGBs was 395 K. This figure was substantially higher than the 38 K liquid film undercooling found within a single dendrite, and far exceeded the undercooling at a low-angle grain boundary (3.6 degrees) with a value of 56 K. The elevated level of stress concentration served as a driving force for crack initiation and propagation. MC-type carbide precipitates promoted crack initiation through a pinning effect on the liquid feed, thereby weakening the interface bonding strength with the substrate.
关键词	single crystal superalloy hot crack additive manufacturing microstructure liquid film stability
资助者	National Key Research and Development Program of China ; China Post-doctoral Science Foundation
DOI	10.11900/0412.1961.2023.00147
收录类别	SCI
语种	英语
资助项目	National Key Research and Development Program of China[2021YFB3702503] ; China Post-doctoral Science Foundation[2022M723211]
WOS研究方向	Metallurgy & Metallurgical Engineering
WOS类目	Metallurgy & Metallurgical Engineering
WOS记录号	WOS:001059082200013
出版者	SCIENCE PRESS
引用统计	被引频次：5[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/321006/179336
专题	中国科学院金属研究所
通讯作者	Li, Jinguo
作者单位	1.Chinese Acad Sci, Inst Met Res, Shichangxu Innovat Ctr Adv Mat, Shenyang 110016, Peoples R China 2.Shenyang Univ Technol, Sch Mat Sci & Engn, Shenyang 110870, Peoples R China 3.AECC Shenyang Liming Aero Engine Co Ltd, Shenyang 110043, Peoples R China
推荐引用方式 GB/T 7714	Lu, Nannan,Guo, Yimo,Yang, Shulin,et al. Formation Mechanisms of Hot Cracks in Laser Additive Repairing Single Crystal Superalloys[J]. ACTA METALLURGICA SINICA,2023,59(9):1243-1252.
APA	Lu, Nannan.,Guo, Yimo.,Yang, Shulin.,Liang, Jingjing.,Zhou, Yizhou.,...&Li, Jinguo.(2023).Formation Mechanisms of Hot Cracks in Laser Additive Repairing Single Crystal Superalloys.ACTA METALLURGICA SINICA,59(9),1243-1252.
MLA	Lu, Nannan,et al."Formation Mechanisms of Hot Cracks in Laser Additive Repairing Single Crystal Superalloys".ACTA METALLURGICA SINICA 59.9(2023):1243-1252.