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

doi:10.11900/0412.1961.2023.00147

Acta Metall Sin

2023, Vol. 59

Issue (9): 1243-1252 DOI: 10.11900/0412.1961.2023.00147

Research paper

Current Issue | Archive | Adv Search

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

LU Nannan¹, GUO Yimo¹^,², YANG Shulin³, LIANG Jingjing¹, ZHOU Yizhou¹, SUN Xiaofeng¹, LI Jinguo¹(

)

¹Shi -changxu Innovation Center for Advanced Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China
²School of Materials Science and Engineering, Shenyang University of Technology, Shenyang 110870, China
³AECC Shenyang Liming Aero-Engine Co., Ltd., Shenyang 110043, China

Cite this article:

LU Nannan, GUO Yimo, YANG Shulin, LIANG Jingjing, ZHOU Yizhou, SUN Xiaofeng, LI Jinguo. Formation Mechanisms of Hot Cracks in Laser Additive Repairing Single Crystal Superalloys. Acta Metall Sin, 2023, 59(9): 1243-1252.

Download:

HTML

PDF(2866KB)
Export: BibTeX | EndNote (RIS)

Abstract

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°) 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.

Key words: single crystal superalloy hot crack additive manufacturing microstructure liquid film stability

Received: 03 April 2023

ZTFLH:

TG665

Fund: National Key Research and Development Program of China(2021YFB3702503);China Postdoctoral Science Foundation(2022M723211)

	Service

	E-mail this article
	Add to citation manager
	E-mail Alert
	RSS
	（）
	Articles by authors
	LU Nannan
	GUO Yimo
	YANG Shulin
	LIANG Jingjing
	ZHOU Yizhou
	SUN Xiaofeng
	LI Jinguo

URL:

https://www.ams.org.cn/EN/10.11900/0412.1961.2023.00147 OR https://www.ams.org.cn/EN/Y2023/V59/I9/1243

Fig.1 Macro-morphology of cracks in the additive manufactured DD432 single crystal (SX) superalloy thinwall specimen

Fig.2 OM image of micromorphology for longitudinal section cracks in the deposition

Fig.3 SEM images of longitudinal crack fracture morphology (a) and liquid film distribution at the crack tip (b)

Fig.4 Morphology and orientation characteristics of the crack initiation region
(a) back scattered electron (BSE) image of the crack initiation region
(b-d) inverse pole figures (IPFs) along the X (b), Y (c), and Z (d) directions, respectively

Fig.5 Kernel Average misorientation (KAM) map of the crack initiation region

Fig.6 Localized amplified microstructure and orientation characteristics in the crack source region (HAGB—high-angle grain boundary, LAGB—low-angle grain boundary)
(a) BSE image of the crack initiation region
(b) enlargement of the selected area in Fig.6a
(c-e) IPFs along the X (c), Y (d), and Z (e) directions, respectively
(f) KAM map of the selected area in Fig.6a

Fig.7 Elemental distribution in the crack source region

Fig.8 BSE image of microstructure (a) and EDS analysis of point 1 (b) near crack initiation

Table 1 Physical parameters used to calculate the undercooling ΔT_b and grain boundary energy γ_gb^[29-31]

Fig.9 Relationships between GB angle (θ) and the dendrite coalescence temperature and GB energy (γ_gb) (T—temperature, θ_c—critical transition angle, θ_m—the angle corresponding to the maximum GB energy, $T b, m i n r$ —the minimum dendrite coalescence temperature for a repulsive boundary, $T b a$ —the dendrite coalescence temperature for an attractive boundary, ΔT_b—dendrite coalescence undercooling ΔT_b,marx—the max dendrite coalescence undercooling)

Fig.10 Relationships between the solidification temperature and the solid fraction (f_s) for DD432 SX superalloys (ΔT_DD432—interdendritic liquid film undercooling in DD432 alloy)

1	Reed R C, Tao T, Warnken N. Alloys-by-design: Application to nickel-based single crystal superalloys [J]. Acta Mater., 2009, 57: 5898 doi: 10.1016/j.actamat.2009.08.018
2	Lopez-Galilea I, Ruttert B, He J Y, et al. Additive manufacturing of CMSX-4 Ni-base superalloy by selective laser melting: Influence of processing parameters and heat treatment [J]. Addit. Manuf., 2019, 30: 100874
3	Pollock T M. Alloy design for aircraft engines [J]. Nat. Mater., 2016, 15: 809 doi: 10.1038/nmat4709 pmid: 27443900
4	Wang L, Wang N, Yao W J, et al. Effect of substrate orientation on the columnar-to-equiaxed transition in laser surface remelted single crystal superalloys [J]. Acta Mater., 2015, 88: 283 doi: 10.1016/j.actamat.2015.01.063
5	Liang Y J, Cheng X, Li J, et al. Microstructural control during laser additive manufacturing of single-crystal nickel-base superalloys: New processing-microstructure maps involving powder feeding [J]. Mater. Des., 2017, 130: 197 doi: 10.1016/j.matdes.2017.05.066
6	Ur Rahman N, Capuano L, Cabeza S, et al. Directed energy deposition and characterization of high-carbon high speed steels [J]. Addit. Manuf., 2019, 30: 100838
7	Zhou Z P, Huang L, Shang Y J, et al. Causes analysis on cracks in nickel-based single crystal superalloy fabricated by laser powder deposition additive manufacturing [J]. Mater. Des., 2018, 160: 1238 doi: 10.1016/j.matdes.2018.10.042
8	Thompson S M, Bian L K, Shamsaei N, et al. An overview of direct laser deposition for additive manufacturing; Part I: Transport phenomena, modeling and diagnostics [J]. Addit. Manuf., 2015, 8: 36
9	Gäumann M, Bezençon C, Canalis P, et al. Single-crystal laser deposition of superalloys: Processing-microstructure maps [J]. Acta Mater., 2001, 49: 1051 doi: 10.1016/S1359-6454(00)00367-0
10	Liang Y J, Wang H M. Origin of stray-grain formation and epitaxy loss at substrate during laser surface remelting of single-crystal nickel-base superalloys [J]. Mater. Des., 2016, 102: 297 doi: 10.1016/j.matdes.2016.04.051
11	Wang L, Wang N. Effect of substrate orientation on the formation of equiaxed stray grains in laser surface remelted single crystal superalloys: Experimental investigation [J]. Acta Mater., 2016, 104: 250 doi: 10.1016/j.actamat.2015.11.018
12	Guo J C, Chen W J, Yang R N, et al. The effect of substrate orientation on stray grain formation in the (111) plane in laser surface remelted single crystal superalloys [J]. J. Alloys Compd., 2019, 800: 240 doi: 10.1016/j.jallcom.2019.06.029
13	Wang L, Wang N, Provatas N. Liquid channel segregation and morphology and their relation with hot cracking susceptibility during columnar growth in binary alloys [J]. Acta Mater., 2017, 126: 302 doi: 10.1016/j.actamat.2016.11.058
14	Wang N, Mokadem S, Rappaz M, et al. Solidification cracking of superalloy single- and bi-crystals [J]. Acta Mater., 2004, 52: 3173 doi: 10.1016/j.actamat.2004.03.047
15	Carter L N, Martin C, Withers P J, et al. The influence of the laser scan strategy on grain structure and cracking behaviour in SLM powder-bed fabricated nickel superalloy [J]. J. Alloys Compd., 2014, 615: 338 doi: 10.1016/j.jallcom.2014.06.172
16	Ruttert B, Ramsperger M, Roncery L M, et al. Impact of hot isostatic pressing on microstructures of CMSX-4 Ni-base superalloy fabricated by selective electron beam melting [J]. Mater. Des., 2016, 110: 720 doi: 10.1016/j.matdes.2016.08.041
17	Ojo O A, Richards N L, Chaturvedi M C. Contribution of constitutional liquation of gamma prime precipitate to weld HAZ cracking of cast Inconel 738 superalloy [J]. Scr. Mater., 2004, 50: 641 doi: 10.1016/j.scriptamat.2003.11.025
18	Chauvet E, Kontis P, Jägle E A, et al. Hot cracking mechanism affecting a non-weldable Ni-based superalloy produced by selective electron Beam Melting [J]. Acta Mater., 2018, 142: 82 doi: 10.1016/j.actamat.2017.09.047
19	Ramakrishnan A, Dinda G P. Direct laser metal deposition of Inconel 738 [J]. Mater. Sci. Eng., 2019, A740-741: 1
20	Boswell J H, Clark D, Li W, et al. Cracking during thermal post-processing of laser powder bed fabricated CM247LC Ni-superalloy [J]. Mater. Des., 2019, 174: 107793 doi: 10.1016/j.matdes.2019.107793
21	Yang J J, Li F Z, Wang Z M, et al. Cracking behavior and control of Rene 104 superalloy produced by direct laser fabrication [J]. J. Mater. Process. Technol., 2015, 225: 229 doi: 10.1016/j.jmatprotec.2015.06.002
22	Dantzig J A, Rappaz M. Solidification [M]. 2nd Edition -Revised & Expanded. Switzerland: EPFL Press, 2016: 618
23	Rong P, Wang N, Wang L, et al. The influence of grain boundary angle on the hot cracking of single crystal superalloy DD6 [J]. J. Alloys Compd., 2016, 676: 181 doi: 10.1016/j.jallcom.2016.03.164
24	Ci S W. Study on microstructure and mechanical properties of nickel-based single crystal superalloy by laser additive manufacturing [D]. Shenyang: University of Science and Technology of China(Institute of Metal Research, CAS), 2021
	慈世伟. 激光增材制造镍基单晶高温合金显微组织和力学性能研究 [D]. 沈阳: 中国科学技术大学(中国科学院金属研究所), 2021
25	Lu N N, Lei Z L, Hu K, et al. Hot cracking behavior and mechanism of a third-generation Ni-based single-crystal superalloy during directed energy deposition [J]. Addit. Manuf., 2020, 34: 101228
26	Rappaz M, Drezet J M, Gremaud M. A new hot-tearing criterion [J]. Metall. Mater. Trans., 1999, 30A: 449
27	Rappaz M, Jacot A, Boettinger W J. Last-stage solidification of alloys: Theoretical model of dendrite-arm and grain coalescence [J]. Metall. Mater. Trans., 2003, 34A: 467
28	Anderson P M, Hirth J P, Lothe J. Theory of Dislocations [M]. 3rd Ed., Cambridge: Cambridge University Press, 2017: 536
29	Academic Committee of the Superalloys. China Superalloys Handbook [M]. Beijing: Standards Press of China, 2012: 589
	中国金属学会高温材料分会. 中国高温合金手册 [M]. 北京: 中国标准出版社, 2012: 589
30	Read W T, Shockley W. Dislocation models of crystal grain boundaries [J]. Phys. Rev., 1950, 78: 275 doi: 10.1103/PhysRev.78.275
31	Asta M, Hoyt J J, Karma A. Calculation of alloy solid-liquid interfacial free energies from atomic-scale simulations [J]. Phys. Rev., 2002, 66B: 100101
32	Kurz W, Fisher D J. Fundamentals of Solidification [M]. 4th Ed., Switzerland: Trans Tech Publications Ltd, 1998: 51
33	Debroy T, Wei H L, Zuback J S, et al. Additive manufacturing of metallic components—Process, structure and properties [J]. Prog. Mater. Sci., 2018, 92: 112 doi: 10.1016/j.pmatsci.2017.10.001
34	Frenk A, Marsden C F, Wagniere J D, et al. Influence of an intermediate layer on the residual stress field in a laser clad [J]. Surf. Coat. Technol., 1991, 45: 435 doi: 10.1016/0257-8972(91)90253-S
35	Mukherjee T, Zhang W, Debroy T. An improved prediction of residual stresses and distortion in additive manufacturing [J]. Comput. Mater. Sci., 2017, 126: 360 doi: 10.1016/j.commatsci.2016.10.003
36	Kattamis T Z, Voorhees P W. Coarsening of solid-liquid mixtures: A review [A]. Proceedings of the Merton C. Flemings Symposium on Solidification and Materials Processing [C]. Cambridge, MA: TMS, 2000: 119
37	Huang Q Y, Li H K. Superalloys [M]. Beijing: Metallurgical Industry Press, 2000: 67
	黄乾尧, 李汉康. 高温合金 [M]. 北京: 冶金工业出版社, 2000: 67

[1]	LI Jiarong, DONG Jianmin, HAN Mei, LIU Shizhong. Effects of Sand Blasting on Surface Integrity and High Cycle Fatigue Properties of DD6 Single Crystal Superalloy[J]. 金属学报, 2023, 59(9): 1201-1208.
[2]	GONG Shengkai, LIU Yuan, GENG Lilun, RU Yi, ZHAO Wenyue, PEI Yanling, LI Shusuo. Advances in the Regulation and Interfacial Behavior of Coatings/Superalloys[J]. 金属学报, 2023, 59(9): 1097-1108.
[3]	WANG Lei, LIU Mengya, LIU Yang, SONG Xiu, MENG Fanqiang. Research Progress on Surface Impact Strengthening Mechanisms and Application of Nickel-Based Superalloys[J]. 金属学报, 2023, 59(9): 1173-1189.
[4]	ZHANG Leilei, CHEN Jingyang, TANG Xin, XIAO Chengbo, ZHANG Mingjun, YANG Qing. Evolution of Microstructures and Mechanical Properties of K439B Superalloy During Long-Term Aging at 800^oC[J]. 金属学报, 2023, 59(9): 1253-1264.
[5]	ZHANG Jian, WANG Li, XIE Guang, WANG Dong, SHEN Jian, LU Yuzhang, HUANG Yaqi, LI Yawei. Recent Progress in Research and Development of Nickel-Based Single Crystal Superalloys[J]. 金属学报, 2023, 59(9): 1109-1124.
[6]	ZHAO Peng, XIE Guang, DUAN Huichao, ZHANG Jian, DU Kui. Recrystallization During Thermo-Mechanical Fatigue of Two High-Generation Ni-Based Single Crystal Superalloys[J]. 金属学报, 2023, 59(9): 1221-1229.
[7]	LI Jingren, XIE Dongsheng, ZHANG Dongdong, XIE Hongbo, PAN Hucheng, REN Yuping, QIN Gaowu. Microstructure Evolution Mechanism of New Low-Alloyed High-Strength Mg-0.2Ce-0.2Ca Alloy During Extrusion[J]. 金属学报, 2023, 59(8): 1087-1096.
[8]	MU Yahang, ZHANG Xue, CHEN Ziming, SUN Xiaofeng, LIANG Jingjing, LI Jinguo, ZHOU Yizhou. Modeling of Crack Susceptibility of Ni-Based Superalloy for Additive Manufacturing via Thermodynamic Calculation and Machine Learning[J]. 金属学报, 2023, 59(8): 1075-1086.
[9]	CHEN Liqing, LI Xing, ZHAO Yang, WANG Shuai, FENG Yang. Overview of Research and Development of High-Manganese Damping Steel with Integrated Structure and Function[J]. 金属学报, 2023, 59(8): 1015-1026.
[10]	LIU Xingjun, WEI Zhenbang, LU Yong, HAN Jiajia, SHI Rongpei, WANG Cuiping. Progress on the Diffusion Kinetics of Novel Co-based and Nb-Si-based Superalloys[J]. 金属学报, 2023, 59(8): 969-985.
[11]	SUN Rongrong, YAO Meiyi, WANG Haoyu, ZHANG Wenhuai, HU Lijuan, QIU Yunlong, LIN Xiaodong, XIE Yaoping, YANG Jian, DONG Jianxin, CHENG Guoguang. High-Temperature Steam Oxidation Behavior of Fe22Cr5Al3Mo-xY Alloy Under Simulated LOCA Condition[J]. 金属学报, 2023, 59(7): 915-925.
[12]	ZHANG Deyin, HAO Xu, JIA Baorui, WU Haoyang, QIN Mingli, QU Xuanhui. Effects of Y₂O₃ Content on Properties of Fe-Y₂O₃ Nanocomposite Powders Synthesized by a Combustion-Based Route[J]. 金属学报, 2023, 59(6): 757-766.
[13]	WANG Fa, JIANG He, DONG Jianxin. Evolution Behavior of Complex Precipitation Phases in Highly Alloyed GH4151 Superalloy[J]. 金属学报, 2023, 59(6): 787-796.
[14]	GUO Fu, DU Yihui, JI Xiaoliang, WANG Yishu. Recent Progress on Thermo-Mechanical Reliability of Sn-Based Alloys and Composite Solder for Microelectronic Interconnection[J]. 金属学报, 2023, 59(6): 744-756.
[15]	FENG Aihan, CHEN Qiang, WANG Jian, WANG Hao, QU Shoujiang, CHEN Daolun. Thermal Stability of Microstructures in Low-Density Ti₂AlNb-Based Alloy Hot Rolled Plate[J]. 金属学报, 2023, 59(6): 777-786.

No Suggested Reading articles found!

Viewed

Full text

Abstract

Cited

Shared

Discussed