Effects of melt convection on stray grain formation in single crystal superalloys during directed energy deposition

doi:10.1016/j.addma.2021.102429

IMR OpenIR

	Effects of melt convection on stray grain formation in single crystal superalloys during directed energy deposition
	Lu, Nannan 1,2; Lei, Zhenglong 1; Yu, Xingfu 3; Bi, Jiang 1; Chen, Yanbin 1
通讯作者	Lei, Zhenglong(leizhenglong@hit.edu.cn)
	2021-12-01
发表期刊	ADDITIVE MANUFACTURING
ISSN	2214-8604
卷号	48 页码:19
摘要	During laser repairing of Ni-based single crystal (SX) superalloys, stray grain (SGs) formation leads to a deterioration of high-temperature properties and hot cracking. The main goal is to prevent SGs formation from forming, which controls the local solidification front thermal gradient (G) and solidification velocity (V). Meanwhile, the melt pool geometry, which is influenced by melt convection, has a significant impact on G and V. Here, experiments and theoretical calculations were used to study the evolution of the melt pool geometry during melt convection and its effects on the formation of SGs. Melt convection, i.e., Marangoni convection, outperformed thermal conduction in the SX superalloys melt pool during directed energy deposition, as evidenced by the estimated Peclet number and Prandtl number. The integrative impact of laser power, scan velocity, and beam diameters exacerbated Marangoni convection as the laser energy density distribution increased. Marangoni convection caused the melt pool shape to change from a near-semicircle to an undulating morphology, promoting the oriented-to-misoriented crystal growth transition and resulting in high stray grain sensitivity. The heat and mass transport in front of the dendrite tips was altered by Marangoni convection, which aggravated the deviation of the epitaxial dendrite orientation with respect to the substrate. This work provides an in-depth insight into controlling SG formation during additive manufacturing of SX superalloys.
关键词	Directed energy deposition Ni-based superalloy Stray grain Marangoni convection Melt pool geometry
DOI	10.1016/j.addma.2021.102429
收录类别	SCI
语种	英语
WOS研究方向	Engineering ; Materials Science
WOS类目	Engineering, Manufacturing ; Materials Science, Multidisciplinary
WOS记录号	WOS:000720745300002
出版者	ELSEVIER
引用统计	被引频次：28[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/321006/167418
专题	中国科学院金属研究所
通讯作者	Lei, Zhenglong
作者单位	1.Harbin Inst Technol, State Key Lab Adv Welding & Joining, Harbin 150001, Peoples R China 2.Chinese Acad Sci, Inst Met Res, Shenyang 110016, Peoples R China 3.Shenyang Univ Technol, Sch Mat Sci & Engn, Shenyang 110178, Peoples R China
推荐引用方式 GB/T 7714	Lu, Nannan,Lei, Zhenglong,Yu, Xingfu,et al. Effects of melt convection on stray grain formation in single crystal superalloys during directed energy deposition[J]. ADDITIVE MANUFACTURING,2021,48:19.
APA	Lu, Nannan,Lei, Zhenglong,Yu, Xingfu,Bi, Jiang,&Chen, Yanbin.(2021).Effects of melt convection on stray grain formation in single crystal superalloys during directed energy deposition.ADDITIVE MANUFACTURING,48,19.
MLA	Lu, Nannan,et al."Effects of melt convection on stray grain formation in single crystal superalloys during directed energy deposition".ADDITIVE MANUFACTURING 48(2021):19.