Review of the Formation Mechanism and Control Technology for Freckle Defects in Directionally Solidified Superalloys

doi:10.11900/0412.1961.2025.00109

Acta Metall Sin

2026, Vol. 62

Issue (2): 309-327 DOI: 10.11900/0412.1961.2025.00109

Overview

Current Issue | Archive | Adv Search

Review of the Formation Mechanism and Control Technology for Freckle Defects in Directionally Solidified Superalloys

JIA Yuliang¹^,², ZHANG Yongjia³, SHI Zekai⁴, SHEN Xu⁴, YIN Yajun⁴, SHI Changkun², ZHOU Jianxin⁴(

), LYU Zhigang¹(

)

1 Department of Mechanical Engineering, Tsinghua University, Beijing 100084, China
2 Anhui Yingliu Hangyuan Power Technology Co. Ltd., Huoshan 237200, China
3 School of Energy and Mechanical Engineering, Jiangxi University of Science and Technology, Nanchang 330013, China
4 State Key Laboratory of Materials Processing and Die & Mould Technology, Huazhong University of Science and Technology, Wuhan 430074, China

Cite this article:

JIA Yuliang, ZHANG Yongjia, SHI Zekai, SHEN Xu, YIN Yajun, SHI Changkun, ZHOU Jianxin, LYU Zhigang. Review of the Formation Mechanism and Control Technology for Freckle Defects in Directionally Solidified Superalloys. Acta Metall Sin, 2026, 62(2): 309-327.

Download:

HTML

PDF(4265KB)
Export: BibTeX | EndNote (RIS)

Abstract

Freckles severely degrade the crystalline integrity and high-temperature mechanical properties of superalloy blades, posing a critical barrier to the fabrication of large-sized directionally solidified blades for heavy-duty gas turbines. This paper reviews the research progress on freckles over the past several decades, both domestically and internationally. It summarizes investigations of elemental segregation, thermo-solutal convection, and dendrite arm fragmentation during freckle formation using techniques such as atom probe tomography, synchrotron radiation, and numerical simulation. Freckle formation criteria based on temperature fields or mushy-zone density have been described, and the influences of blade geometry and solidification parameters on freckle distribution have been elucidated. Moreover, freckle control techniques and methods are comprehensively reviewed. At present, most studies on freckles focus on cases involving “small-sized specimens, low withdrawal rates (≤ 1.5 mm/min), and alloys with high W/Re contents”, which exhibit relatively significant differences from the freckle solidification conditions and occurrence patterns of “large blades, high withdrawal rates (≥ 2.0 mm/min), and alloys with low W/Re content” in the engineering practice of heavy-duty gas turbines. Therefore, developing rapid freckle prediction methods and effective control technologies specifically suited to the solidification conditions of large blades in heavy-duty gas turbines has become a critical need and a key research direction for the present and future.

Key words: large-scale blade directional solidification superalloy freckle numerical modeling

Received: 14 April 2025

ZTFLH:

TG245

Fund: National Key Research and Development Program of China(2024YFB3713805);Basic Research Program(JCKY-C102)

Corresponding Authors: LYU Zhigang, professor, Tel: 13701333592, E-mail: lvzg@tsinghua.edu.cn;
ZHOU Jianxin, professor, Tel: 13871482400, E-mail: zhoujianxin@hust.edu.cn

	Service

	E-mail this article
	Add to citation manager
	E-mail Alert
	RSS
	（）
	Articles by authors
	JIA Yuliang
	ZHANG Yongjia
	SHI Zekai
	SHEN Xu
	YIN Yajun
	SHI Changkun
	ZHOU Jianxin
	LYU Zhigang

URL:

https://www.ams.org.cn/EN/10.11900/0412.1961.2025.00109 OR https://www.ams.org.cn/EN/Y2026/V62/I2/309

Fig.1 Freckle defects and its formation mechanism of the large-sized industrial gas turbine blade^[16] (a-c) freckle chains (showed by arrows) (a), dendritic crystal (b), and orientation images (c) of freckle chains (IPF—inverse pole figure) (d) schematic of formation mechanism of freckle defects

Fig.2 Freckle defects: microstructure in electron microscopy and composition obtained by atom probe tomography (APT)^[12]
(a) SEM image displaying the four regions of interest (ROIs): the dendritic cores in the single crystal (SC-DC) and in the freckles (F-DC); the inter-dendritic regions in the SC (SC-ID) and in the freckles (F-ID)
(b-e) 3D APT reconstructions of samples lifted-out from the four ROIs
(f, g) Al, Cr, Co, Mo, Ta, W, and Re element concentrations in four ROIs

Fig.3 Distributions of freckle chains on blades with different alloy compositions^[18]
(a) UCSX6 (b) UCSX7 (On the basis of UCSX6, add 1.5%Cr and 3.0%Mo, mass fraction)
(c) UCSX8 (On the basis of UCSX7, add 2% Ta, and reduce 2%W and 0.8%Re, mass fraction)

Fig.4 Experimental observation of channel segregation (a1, a2) upward jet flow parallel to gravity direction in NH₄Cl solution (a1) and jet flow on the top side (a2)^[11] (b1, b2) segregation channels (indicated by arrows) in Pb-2%Sb alloy (mass fraction, the same below) in different sections^[21] (c1, c2) solute plumes during directional solidification of CMSX-4 alloy^[13] (R—cooling rate, white arrows show the dendrite tips)

Fig.5 Simulation results of channel segregation during directional solidification
(a1, a2) velocity field (a1) and normalized concentration field (a2) of Ti element in CMSX2 alloy^[23] (C_mix—mixture concentration, C_in—initial concentration)
(b1, b2) isosurfaces of liquid volume fraction (Color of streamtraces indicates mixture concentration of Sn, with corresponding levels shown in the upper color bar) (b1) and segregation channels of Sn (b2) during directional solidification of Pb-10%Sn^[14]
(c1, c2) velocity field and segregation channels^[30] (f_s—solid volume fraction, u_l—velocity of the melt, t—time, T_eut—eutectic temperature)

Fig.6 Convection velocity near the convergence grain boundary by cellular automation simulation^[36] (a1, a2) experimental results (Fig.6a2 is the corresponding magnified view) (b) simulation result

Fig.7 Phase field simulation results of dendrite morphology and solute concentration distribution during directional solidification of CMSX-4 alloy^[46]
(a) dendrite deflection (G—temperature gradient, a—crystal growth direction)
(b) dendrite remelt and protrude (c) dendrite branch and overgrowth

Fig.8 Isolated dendrites near solidification front
(a1, a2) convergence grain boundary (a1) and fractured dendrites (a2) in NH₄Cl solution^[11] (White arrow indicates the direction of the convective jet eroding the mushy zone)
(b1, b2) occurrence of isolated grains at time of 115 s (b1) and 135 s (b2) during directional solidification of Ga-25%In alloy by synchrotron radiation observation^[52] (Numbers 1 and 2 represent grains)

Fig.9 Freckle formation map of CMSX-4 alloy with different temperature gradients and solidification rates^[56]

Fig.10 Mushy zones and velocity fields for René N4 alloy (a1, a2) and Ni-Al-W alloy (b1, b2)^[64] (a1, b1) reconstructed morphologies (a2, b2) simulated velocity fields

Table 1 Influence factors of freckle formation

Fig.11 Freckle distributions of sample with varied cross-sections (a, b) samples with increased section (a) and decreased section (b)^[58] (ΔZ indicates the incubation distance for the freckle onset after varying the specimen diameter. A, B, and C represent the freckle chains. Yellow, red, green, and blue arrows represent radiation lines) (c) freckle chains on sample with increased and decreased sections^[66]

Table 2 Sample size, withdrawal rate, and alloy composition of sample with freckles in the literatures [9,30,58-60,72,73]

Table 3 Alloy elements affecting solute convection

[1]	Broomfield R W, Ford D A, Bhangu J K, et al. Development and turbine engine performance of three advanced rhenium containing superalloys for single crystal and directionally solidified blades and vanes [J]. J. Eng. Gas. Turbines Power, 1998, 120: 595 doi: 10.1115/1.2818188
[2]	Reed R C. The Superalloys: Fundamentals and Applications [M]. Cambridge: Cambridge University Press, 2006: 1
[3]	Pollock T M, Argon A S. Creep resistance of CMSX-3 nickel base superalloy single crystals [J]. Acta Metall. Mater., 1992, 40: 1 doi: 10.1016/0956-7151(92)90195-K
[4]	Versnyder F I, Shank M E. The development of columnar grain and single crystal high temperature materials through directional solidification [J]. Mater. Sci. Eng., 1970, 6: 213 doi: 10.1016/0025-5416(70)90050-9
[5]	Quested P N, Osgerby S. Mechanical properties of conventionally cast, directionally solidified, and single-crystal superalloys [J]. Mater. Sci. Technol., 1986, 2: 461 doi: 10.1179/mst.1986.2.5.461
[6]	Szeliga D, Kubiak K, Sieniawski J. Control of liquidus isotherm shape during solidification of Ni-based superalloy of single crystal platforms [J]. J. Mater. Process. Technol., 2016, 234: 18 doi: 10.1016/j.jmatprotec.2016.03.003
[7]	Mathur H N, Panwisawas C, Jones C N, et al. Nucleation of recrystallisation in castings of single crystal Ni-based superalloys [J]. Acta Mater., 2017, 129: 112 doi: 10.1016/j.actamat.2017.02.058
[8]	Tin S, Pollock T M, Murphy W. Stabilization of thermosolutal convective instabilities in Ni-based single-crystal superalloys: Carbon additions and freckle formation [J]. Metall. Mater. Trans., 2001, 32A: 1743
[9]	Giamei A F, Kear B H. On the nature of freckles in nickel base superalloys [J]. Metall. Trans., 1970, 1: 2185 doi: 10.1007/BF02643434
[10]	Pollock T M, Murphy W H. The breakdown of single-crystal solidification in high refractory nickel-base alloys [J]. Metall. Mater. Trans., 1996, 27A: 1081
[11]	Copley S M, Giamei A F, Johnson S M, et al. The origin of freckles in unidirectionally solidified castings [J]. Metall. Trans., 1970, 1: 2193 doi: 10.1007/BF02643435
[12]	Amouyal Y, Seidman D N. An atom-probe tomographic study of freckle formation in a nickel-based superalloy [J]. Acta Mater., 2011, 59: 6729 doi: 10.1016/j.actamat.2011.07.030
[13]	Reinhart G, Grange D, Abou-Khalil L, et al. Impact of solute flow during directional solidification of a Ni-based alloy: In-situ and real-time X-radiography [J]. Acta Mater., 2020, 194: 68 doi: 10.1016/j.actamat.2020.04.003
[14]	Felicelli S D, Heinrich J C, Poirier D R. Three-dimensional simulations of freckles in binary alloys [J]. J. Cryst. Growth, 1998, 191: 879 doi: 10.1016/S0022-0248(98)00357-1
[15]	Pollock T M, Murphy W H, Goldman E H, et al. Grain defect formation during directional solidification of nickel base single crystals [A]. Superalloys 1992 [C]. Pennsylvania: TMS, 1992: 125
[16]	Wang S, Jia Y L, Wang Y Z, et al. New vision of convection induced freckle formation theory in nickel-based superalloys by electron microscopy [J]. Microstructures, 2024, 4: 2024006
[17]	Tin S, Pollock T M, King W T. Carbon additions and grain defect formation in high refractory nickel-base single crystal superalloys [A]. Proceedings of the 9th International Symposium on Superalloys [C]. Pennsylvania: TMS, 2000: 201
[18]	Hobbs R A, Tin S, Rae C M F. A castability model based on elemental solid-liquid partitioning in advanced nickel-base single-crystal superalloys [J]. Metall. Mater. Trans., 2005, 36A: 2761
[19]	Amouyal Y, Seidman D N. The role of hafnium in the formation of misoriented defects in Ni-based superalloys: An atom-probe tomographic study [J]. Acta Mater., 2011, 59: 3321 doi: 10.1016/j.actamat.2011.02.006
[20]	Bao C J, Li Z F, Liu F, et al. Modeling of constituent-based freckle predictor for nickel-base superalloys [J]. Chin. J. Nonferrous Met., 2019, 29: 998
	包超君, 李振锋, 刘锋等. 一种基于镍基高温合金成分的雀斑预测模型 [J]. 中国有色金属学报, 2019, 29: 998
[21]	Sarazin J R, Hellawell A. Channel formation in Pb-Sn, Pb-Sb, and Pb-Sn-Sb alloy ingots and comparison with the system NH₄Cl-H₂O [J]. Metall. Trans., 1988, 19A: 1861
[22]	Shevchenko N, Boden S, Eckert S, et al. Observation of segregation freckle formation under the influence of melt convection [J]. IOP Conf. Ser.: Mater. Sci. Eng., 2012, 27: 012085
[23]	Schneider M C, Gu J P, Beckermann C, et al. Modeling of micro- and macrosegregation and freckle formation in single-crystal nickel-base superalloy directional solidification [J]. Metall. Mater. Trans., 1997, 28A: 1517
[24]	Saad A, Gandin C A, Bellet M, et al. Simulation of channel segregation during directional solidification of In-75 wt pct Ga. qualitative comparison with in situ observations [J]. Metall. Mater. Trans., 2015, 46A: 4886
[25]	Felicelli S D. Simulation of freckles during vertical solidification of binary alloys [D]. Arizona: The University of Arizona, 1991
[26]	Frueh C, Poirier D R, Felicelli S D. Predicting freckle-defects in directionally solidified Pb-Sn alloys [J]. Mater. Sci. Eng., 2002, A328: 245
[27]	Gu J P, Beckermann C, Giamei A F. Motion and remelting of dendrite fragments during directional solidification of a nickel-base superalloy [J]. Metall. Mater. Trans., 1997, 28A: 1533
[28]	Ren N, Li J, Panwisawas C, et al. Thermal-solutal-fluid flow of channel segregation during directional solidification of single-crystal nickel-based superalloys [J]. Acta Mater., 2021, 206: 116620 doi: 10.1016/j.actamat.2020.116620
[29]	Ren N, Li J, Panwisawas C, et al. Insight into the sensitivities of freckles in the directional solidification of single-crystal turbine blades [J]. J. Manuf. Processes, 2022, 77: 219 doi: 10.1016/j.jmapro.2022.03.019
[30]	Zhang H J, Liu X S, Ma D X, et al. Digital twin for directional solidification of a single-crystal turbine blade [J]. Acta Mater., 2023, 244: 118579 doi: 10.1016/j.actamat.2022.118579
[31]	Wu M, Ludwig A. Using a three-phase deterministic model for the columnar-to-equiaxed transition [J]. Metall. Mater. Trans., 2007, 38A: 1465
[32]	Zhang H J, Zhao Y X, Xiong W, et al. Modelling freckles and spurious grain formation in directionally solidified superalloy castings [J]. Commun. Mater., 2024, 5: 232 doi: 10.1038/s43246-024-00672-4
[33]	Liu Y, Wang F, Ma D X, et al. Freckle prediction model incorporating geometrical effects for Ni-based single-crystal superalloy components [J]. Acta Mater., 2024, 266: 119702 doi: 10.1016/j.actamat.2024.119702
[34]	Yuan L, Lee P D. A new mechanism for freckle initiation based on microstructural level simulation [J]. Acta Mater., 2012, 60: 4917 doi: 10.1016/j.actamat.2012.04.043
[35]	Kao A, Shevchenko N, Alexandrakis M, et al. Thermal dependence of large-scale freckle defect formation [J]. Philos. Trans. Roy. Soc., 2019, 377A: 20180206
[36]	Karagadde S, Yuan L, Shevchenko N, et al. 3-D microstructural model of freckle formation validated using in situ experiments [J]. Acta Mater., 2014, 79: 168 doi: 10.1016/j.actamat.2014.07.002
[37]	Takaki T, Rojas R, Sakane S, et al. Phase-field-lattice Boltzmann studies for dendritic growth with natural convection [J]. J. Cryst. Growth, 2017, 474: 146 doi: 10.1016/j.jcrysgro.2016.11.099
[38]	Ohno M, Takaki T, Shibuta Y. Numerical testing of quantitative phase-field models with different polynomials for isothermal solidification in binary alloys [J]. J. Comput. Phys., 2017, 335: 621 doi: 10.1016/j.jcp.2017.01.053
[39]	Rojas R, Takaki T, Ohno M. A phase-field-lattice Boltzmann method for modeling motion and growth of a dendrite for binary alloy solidification in the presence of melt convection [J]. J. Comput. Phys., 2015, 298: 29 doi: 10.1016/j.jcp.2015.05.045
[40]	Sakane S, Takaki T, Ohno M, et al. Acceleration of phase-field lattice Boltzmann simulation of dendrite growth with thermosolutal convection by the multi-GPUs parallel computation with multiple mesh and time step method [J]. Modell. Simul. Mater. Sci. Eng., 2019, 27: 054004
[41]	Takaki T, Sakane S, Ohno M, et al. Large-scale phase-field lattice Boltzmann study on the effects of natural convection on dendrite morphology formed during directional solidification of a binary alloy [J]. Comput. Mater. Sci., 2020, 171: 109209 doi: 10.1016/j.commatsci.2019.109209
[42]	Watanabe S, Aoki T. Large-scale flow simulations using lattice Boltzmann method with AMR following free-surface on multiple GPUs [J]. Comput. Phys. Commun., 2021, 264: 107871 doi: 10.1016/j.cpc.2021.107871
[43]	Sakane S, Aoki T, Takaki T. Parallel GPU-accelerated adaptive mesh refinement on two-dimensional phase-field lattice Boltzmann simulation of dendrite growth [J]. Comput. Mater. Sci., 2022, 211: 111507 doi: 10.1016/j.commatsci.2022.111507
[44]	Guo Z, Mi J, Grant P S. An implicit parallel multigrid computing scheme to solve coupled thermal-solute phase-field equations for dendrite evolution [J]. J. Comput. Phys., 2012, 231: 1781 doi: 10.1016/j.jcp.2011.11.006
[45]	Guo Z, Mi J, Xiong S, et al. Phase field study of the tip operating state of a freely growing dendrite against convection using a novel parallel multigrid approach [J]. J. Comput. Phys., 2014, 257: 278 doi: 10.1016/j.jcp.2013.10.004
[46]	Yang C, Xu Q Y, Liu B C. Study of dendrite growth with natural convection in superalloy directional solidification via a multiphase-field-lattice Boltzmann model [J]. Comput. Mater. Sci., 2019, 158: 130 doi: 10.1016/j.commatsci.2018.11.024
[47]	Steinbach I, Pezzolla F, Nestler B, et al. A phase field concept for multiphase systems [J]. Physica, 1996, 94D: 135
[48]	Eiken J, Böttger B, Steinbach I. Multiphase-field approach for multicomponent alloys with extrapolation scheme for numerical application [J]. Phys. Rev., 2006, 73E: 066122
[49]	Yang C, Xu Q Y, Liu B C. A high precision extrapolation method in multiphase-field model for simulating dendrite growth [J]. J. Cryst. Growth, 2018, 490: 25 doi: 10.1016/j.jcrysgro.2018.03.017
[50]	Yasuda H, Yamamoto Y, Nakatsuka N, et al. In situ observation of nucleation, fragmentation and microstructure evolution in Sn-Bi and Al-Cu alloys [J]. Int. J. Cast Met. Res., 2008, 21: 125 doi: 10.1179/136404608X361800
[51]	Ruvalcaba D, Mathiesen R H, Eskin D G, et al. In situ observations of dendritic fragmentation due to local solute-enrichment during directional solidification of an aluminum alloy [J]. Acta Mater., 2007, 55: 4287 doi: 10.1016/j.actamat.2007.03.030
[52]	Shevchenko N, Boden S, Gerbeth G, et al. Chimney formation in solidifying Ga-25wt pct in alloys under the influence of thermosolutal melt convection [J]. Metall. Mater. Trans., 2013, 44A: 3797
[53]	Soar P, Kao A, Djambazov G, et al. The integration of structural mechanics into microstructure solidification modelling [J]. IOP Conf. Ser.: Mater. Sci. Eng., 2020, 861: 012054
[54]	Ren N, Panwisawas C, Li J, et al. Solute enrichment induced dendritic fragmentation in directional solidification of nickel-based superalloys [J]. Acta Mater., 2021, 215: 117043 doi: 10.1016/j.actamat.2021.117043
[55]	Rutter J W, Chalmers B. A Prismatic substructure formed during the solidification of metals [J]. Canadian Journal of Physics. 1952, 3: 15
[56]	Schadt R, Wagner I, Preuhs J, et al. New aspects of freckle formation during single crystal solidification of CMSX-4 [A]. Superalloys 2000 [C]. Pennsylvania: TMS, 2000: 211
[57]	Li Q D, Shen J, Xiong Y L, et al. Prediction of freckle formation in directionally solidified CMSX-4 superalloy [J]. Mater. Lett., 2018, 228: 281 doi: 10.1016/j.matlet.2018.06.002
[58]	Ma D X, Wu Q, Bührig-Polaczek A. Some new observations on freckle formation in directionally solidified superalloy components [J]. Metall. Mater. Trans., 2012, 43B: 344
[59]	Han D Y, Jiang W G, Xiao J H, et al. Investigation on freckle formation and evolution of single-crystal nickel-based superalloy specimens with different thicknesses and abrupt cross-section changes [J]. J. Alloys Compd., 2019, 805: 218 doi: 10.1016/j.jallcom.2019.07.045
[60]	Wu H Z, Xuan W D, Zhang X Y, et al. Investigation of mechanism for formation of freckle during directional solidification of Ni base single crystal superalloy [J]. Hot Work. Technol., 2025, 54(3): 120
	吴怀洲, 玄伟东, 张翔宇等. 镍基单晶高温合金定向凝固雀斑形成机理研究 [J]. 热加工工艺, 2025, 54(3): 120
[61]	Tin S, Pollock T M. Predicting freckle formation in single crystal Ni-base superalloys [J]. J. Mater. Sci., 2004, 39: 7199 doi: 10.1023/B:JMSC.0000048732.02111.ee
[62]	Worster M G. Instabilities of the liquid and mushy regions during solidification of alloys [J]. J. Fluid Mech., 1992, 237: 649 doi: 10.1017/S0022112092003562
[63]	Beckermann C, Gu J P, Boettinger W J. Development of a freckle predictor via Rayleigh number method for single-crystal nickel-base superalloy castings [J]. Metall. Mater. Trans., 2000, 31A: 2545
[64]	Madison J, Spowart J E, Rowenhorst D J, et al. Fluid flow and defect formation in the three-dimensional dendritic structure of nickel-based single crystals [J]. Metall. Mater. Trans., 2012, 43A: 369
[65]	Hong J P, Ma D X, Wang J, et al. Freckle defect formation near the casting interfaces of directionally solidified superalloys [J]. Materials, 2016, 9: 929 doi: 10.3390/ma9110929
[66]	Ma D X. Freckle formation during directional solidification of complex castings of superalloys [J]. Acta Metall. Sin., 2016, 52: 426
	马德新. 定向凝固的复杂形状高温合金铸件中的雀斑形成 [J]. 金属学报, 2016, 52: 426 doi: 10.11900/0412.1961.2015.00379
[67]	Monde A D, Shrivastava A, Jakhar A, et al. Binary alloy solidification and freckle formation: effect of shrinkage induced flow on solutal instability and macro-segregation [J]. Phys. Fluids, 2021, 33: 037108
[68]	Zhang H J, Wu M H, Tewari S N, et al. Geometrical effect on macrosegregation formation during unidirectional solidification of Al-Si alloy [J]. J. Mater. Process. Technol., 2021, 288: 116913 doi: 10.1016/j.jmatprotec.2020.116913
[69]	Ma D X, Bührig-Polaczek A. The influence of surface roughness on freckle formation in directionally solidified superalloy samples [J]. Metall. Mater. Trans., 2012, 43B: 671
[70]	Zhang Y J, Jia Y L, Zhou J X, et al. Effect of withdrawal rate on freckle formation of large-size directional solidified nickel-based superalloy blades [J]. J. Mater. Res. Technol., 2024, 30: 1518 doi: 10.1016/j.jmrt.2024.03.139
[71]	Qin L, Shen J, Yang G X, et al. A design of non-uniform thickness mould for controlling temperature gradient and S/L interface shape in directionally solidified superalloy blade [J]. Mater. Des., 2017, 116: 565 doi: 10.1016/j.matdes.2016.12.071
[72]	Ren Y. Numerical simulation of freckle defects in nickel-based superalloys [D]. Harbin: Harbin University of Science and Technology, 2019
	任莹. 镍基高温合金雀斑缺陷数值模拟研究 [D]. 哈尔滨理工大学, 2019
[73]	Qin L, Shen J, Li Q D, et al. Effects of convection patterns on freckle formation of directionally solidified nickel-based superalloy casting with abruptly varying cross-sections [J]. J. Cryst. Growth, 2017, 466: 45 doi: 10.1016/j.jcrysgro.2017.03.021
[74]	Zhang J, Lou L H, Li H. Material and processing technology of directionally solidified blade in heavy duty industrial gas turbines [J]. Mater. China, 2013, 32(1): 12
	张健, 楼琅洪, 李辉. 重型燃气轮机定向结晶叶片的材料与制造工艺 [J]. 中国材料进展, 2013, 32(1): 12
[75]	Elliott A J, Pollock T M, Tin S, et al. Directional solidification of large superalloy castings with radiation and liquid-metal cooling: A comparative assessment [J]. Metall. Mater. Trans., 2004, 35A: 3221
[76]	Song J S, Wang F, Jia S, et al. Liquid metal cooling furnace for large-sized single crystal blades [J]. Vacuum. 2025, 62(01): 67
	宋静思, 王富, 贾石等. 用于大尺寸叶片的液态金属冷却单晶炉 [J]. 真空. 2025, 62(01): 67
[77]	Wang Z C, Li J R, Liu S Z, et al. Effects of shell mold heating temperature on microstructures and freckle formation of single crystal superalloys [J]. Trans. Nonferrous Met. Soc. China, 2024, 34: 1191 doi: 10.1016/S1003-6326(24)66463-0
[78]	Li Q D, Shen J, Qin L, et al. Investigation on local cooling in reducing freckles for directionally solidified superalloy specimens with abruptly varying cross-sections [J]. Mater. Charact., 2017, 130: 139 doi: 10.1016/j.matchar.2017.05.032
[79]	Wang F, Ma D X, Zhang J, et al. Investigation of segregation and density profiles in the mushy zone of CMSX-4 superalloys solidified during downward and upward directional solidification processes [J]. J. Alloys Compd., 2015, 620: 24 doi: 10.1016/j.jallcom.2014.09.103
[80]	Li Z F, Hu B, Zhong W H, et al. Study on formation mechanism of casting defects in directionally solidified blades of DZ22B superalloy [J]. Aeron. Manuf. Technol., 2020, 63(16): 45
	李振锋, 胡兵, 钟文惠等. DZ22B高温合金定向凝固叶片铸造缺陷的形成机理研究 [J]. 航空制造技术, 2020, 63(16): 45
[81]	Li Q D, Shen J, Qin L, et al. Effect of traveling magnetic field on freckle formation in directionally solidified CMSX-4 superalloy [J]. J. Mater. Process. Technol., 2019, 274: 116308 doi: 10.1016/j.jmatprotec.2019.116308
[82]	Zhang Y J, Zhou J X, Yin Y J, et al. Numerical simulation of dendrite growth and solute convection during directional solidification of superalloy [J]. J. Netshape Forming Eng., 2023, 15(10): 13
	张勇佳, 周建新, 殷亚军等. 高温合金定向凝固过程中枝晶生长与溶质对流数值模拟 [J]. 精密成形工程, 2023, 15(10): 13
[83]	Richter A R, Scholz F, Eggeler G, et al. Microstructure informatics: using computer vision for the characterization of dendrite growth phenomena in Ni-base single crystal Superalloys [J]. Mater. Charact., 2025, 223: 114878 doi: 10.1016/j.matchar.2025.114878
[84]	Kavousi S, Asle Zaeem M. Integration of multiscale simulations and machine learning for predicting dendritic microstructures in solidification of alloys [J]. Acta Mater., 2025, 289: 120860 doi: 10.1016/j.actamat.2025.120860

[1]	ZHAO Xiao, XU Chao, JIANG He, YAO Zhihao, DONG Jianxin. Effect and Characterization of O Accumulation Degree on Fatigue Properties and Grain Boundary Damage in GH4738 Ni-Based Superalloy[J]. 金属学报, 2026, 62(2): 328-338.
[2]	GUO Shijia, LI Jianyue, YUAN Shengyun, LI Zhigang, YU Lianxu, ZHANG Yong. High-Temperature Oxidation Behaviors and γ' Phase Stability of a New Fourth-Generation Single Crystal Superalloy with Rare Earth[J]. 金属学报, 2026, 62(2): 351-362.
[3]	YAN Jing, ZHANG Jiali, DENG Rui, HE Yang, WEN Xinli, ZHANG Qingquan, QIAO Lijie. Burning Loss Mechanism of Sc During Vacuum Induction Melting of Nickel-Based Superalloys[J]. 金属学报, 2026, 62(2): 363-371.
[4]	WANG Hongying, YAO Zhihao, LI Dayu, GUO Jing, YAO Kaijun, DONG Jianxin. Similarities and Differences of Microstructure and Mechanical Properties Between High γ' Content Powder and Wrought Superalloys[J]. 金属学报, 2025, 61(9): 1364-1374.
[5]	ZHANG Tianhao, JU Quan, MENG Zhaobin, WANG Hao, HU Benfu. Microstructural Stability in Tungsten Argon-Arc Welded Joint of GH3230 Superalloy Plate[J]. 金属学报, 2025, 61(9): 1375-1386.
[6]	XIE Xinliang, ZHOU Liping, YU Jianbo, XUAN Weidong, CHEN Chaoyue, WANG Jiang, REN Zhongming. Effect of Weak Transverse Magnetic Field on the Competitive Grain Growth of Ni-Based Superalloy with Divergent Bi-Crystals[J]. 金属学报, 2025, 61(8): 1203-1216.
[7]	HE Jiabao, WANG Liang, ZHANG Chaowei, ZOU Mingke, MENG Jie, WANG Xinguang, JIANG Sumeng, ZHOU Yizhou, SUN Xiaofeng. Effect of Al₂O₃ Coating on Interface Reaction Between Si-Based Ceramic Core and Ni-Based Single-Crystal Superalloy[J]. 金属学报, 2025, 61(7): 1093-1108.
[8]	WANG Feixiang, CHEN Zhongfeng, YIN Xiaoyu, XIONG Lianghua, XIE Honglan, DENG Biao, XIAO Tiqiao. In Situ Observation of Three-Dimensional Solidification Microstructure of Superalloy Melt Based on X-Ray Stereo Imaging[J]. 金属学报, 2025, 61(7): 1109-1118.
[9]	LI Yongmei, TAN Zihao, WANG Xinguang, TAO Xipeng, YANG Yanhong, LIU Jide, LIU Jinlai, LI Jinguo, ZHOU Yizhou, SUN Xiaofeng. Oxidation Behavior of a Low-Cost Third-Generation Ni-Based Single-Crystal Superalloy[J]. 金属学报, 2025, 61(7): 1049-1059.
[10]	LI Dayu, YAO Zhihao, ZHAO Jie, DONG Jianxin, GUO Jing, ZHAO Yu. Evolution of Microstructure and Mechanical Properties of FGH4720Li P/M Superalloy Under Near-Service Conditions[J]. 金属学报, 2025, 61(6): 826-836.
[11]	LI Xinyu, BAI Jiaming, ZHANG Haopeng, LI Xiaokun, JIA Jian, LIU Changsheng, LIU Jiantao, ZHANG Yiwen. Creep Behavior of Advanced Powder Metallurgy Nickel-Based Superalloys FGH4108 Under Different Stress Conditions[J]. 金属学报, 2025, 61(5): 757-769.
[12]	ZHOU Yiming, HAN Yongjun, XIE Guang, ZHENG Wei, XIAO Yanbin, PAN Yang, ZHANG Jian. High-Temperature Corrosion Behavior of a Nickel-Based Superalloy in HCl-Containing Atmosphere[J]. 金属学报, 2025, 61(5): 770-782.
[13]	YANG Minghui, LI Xingwu, SUN Chonghao, RUAN Ying. Microstructure and Mechanical Properties of Monel K-500 Alloy in Synergetic Modulation of Directional Solidification and Thermal Processing[J]. 金属学报, 2025, 61(4): 561-571.
[14]	ZHANG Haopeng, BAI Jiaming, LI Xinyu, LI Xiaokun, JIA Jian, LIU Jiantao, ZHANG Yiwen. Effect of Hf and Ta on Creep Rupture Characteristics and Properties of Powder Metallurgy Ni-Based Superalloys[J]. 金属学报, 2025, 61(4): 583-596.
[15]	ZHOU Shengyu, HU Minghao, LI Chong, DING Haimin, GUO Qianying, LIU Yongchang. *Creep Behavior of a Ni-Based Superalloy with Strengthening of γ' and γ''* Phases**[J]. 金属学报, 2025, 61(2): 226-234.

No Suggested Reading articles found!

Viewed

Full text

Abstract

Cited

Shared

Discussed