Long Time Stability of Direct Aging GH4169G Alloy Forging Disc after Thermal Exposure at 650°C

Abstract:

An isothermal aging study was carried out on direct aging GH4169G alloy forging disk for up to 10000 hours at 650°C. The evolution of microstructure and mechanical properties of the alloy were systematically studied via scanning electron microscope (SEM), transmission electron microscope (TEM) and physicochemical phase analysis. The results show that the size of main strengthening phases γ′′ and γ′ in GH4169G alloy direct aging disk increases gradually, while their quantity decreases with prolonging aging time. The total amount of γ′′ and γ′ is 14.1% at as-heat treated condition, which decreases by 3.1% at 10000h. The amount of δ phase increases gradually, and the content of δ phase reaches 5.4% at 10000h, which increases nearly twice. The α-Cr phase adjacent to the δ phase on the grain boundaries shows a parabolic increase in its content, and reaches 2.231% at 10000h. The yield strength, stress rupture life shows varying degrees of reductions as prolonging thermal aging time.

• Periodical: Materials Science Forum (Volume 1072)
• Pages: 129-135
• DOI: https://doi.org/10.4028/p-nk84f2
• Online since: October 2022
• Authors: Shu Hong Fu*, Zhao Li, Ya Zhou Zhang, Tao Wang
• Keywords: GH4169G Alloy, Long Time Stability, Microstructure, Superalloy

References

[1] Sun W R, Xin X, Yu L X, et al. Effect of Phosphorus and Boron on the Long-Term Aging Stability of GH4169 Alloy at 650℃. 13th China Superalloys Conference. Beijing, PA: Metallurgical Industry Press, 2016: 89-92.

[2] Jia D, Sun W R, Xu D S, et al. Dynamic recrystallization behavior of GH4169G alloy during hot compressive deformation[J]. Journal of Materials Science & Technology, 2019, 35(9): 1851-1859.

DOI: 10.1016/j.jmst.2019.04.018

[3] Li Z J, Bai Y R. The failure study on blade tip crack of GH4169G alloy blisk[J]. Gas Turbine Experiment and Research, 2020, 33(5): 54-58.

[4] Sun K, Lin H B, He Y B, et al. Microscopic Inspection and Improvement of GH4169G Alloy Forging Banded Structure Defects[J]. Special Casting & Nonferrous Alloys, 2020, 40(6): 694-696.

[5] Liu Q M, Huang S Z, Chen Y L, et al. Investigation on the abnormal corrosion spots of GH4169G alloy parts[J]. Gas Turbine Experiment and Research, 2019, 32(1): 52-56.

[6] Wang L H, Liu Z L, Liu X Q, et al. Effects of Al and Ti Contents on the Microstructure and Solidification Behavior of Cast Inconel 718[J]. Journal of Materials Science and Engineering, 2016, 34(2): 242-247.

[7] Fu S H, Dong J X, Zhang M C, et al. Thermodynamic Calculation of the Phases Precipitation Behavior for Developing 718 Type Alloys with High Structure Stability[J]. Journal of Materials Engineering, 2009, (11): 8-13.

[8] Dheepa S. Effect of long-time exposure on the evolution of minor phases in Alloy 718[J]. Materials Science and Engineering A, 2004, 364: 27-34.

DOI: 10.1016/j.msea.2003.06.003

[9] John F R, Bernard H L. Effect of thermal Exposure on Microstructural Evolution in Alloy 718 Fasteners. Superalloys 718, 625, 706 and Various Derivatives. Pittsburgh, PA: TMS, 2001: 433-442.

DOI: 10.7449/2001/superalloys_2001_433_442

[10] Leonardo S A, Clarissa Hadad de M, Rodrigo P G, et al. The effect of a very high overheating on the microstructural degradation of superalloy 718[J]. Journal of Materials Research and Technology, 2018, 8(1): 683-689.

[11] Yusaku H, Koichi T O, Eiji M, et al. Grain Boundary Precipitation Strengthening of Fe Base Superalloy GH4169[J], Acta Metallurgica Sinica, 2010, 46 (11): 1289-1302.

DOI: 10.3724/sp.j.1037.2010.01289

[12] Xie X S, Dong J X, Fu S H, et al. Research and Development of γ" and γ' Strengthened Ni-Fe Base Superalloy GH4169[J], Acta Metallurgica Sinica, 2010, 46 (11): 1289-1302.

DOI: 10.3724/sp.j.1037.2010.01289

[13] Rafiei M, Mirzadeh H, Malekan M. Micro-mechanisms and precipitation kinetics of delta (δ) phase in Inconel 718 superalloy during aging [J]. Journal of Alloys and Compounds, 2019,795: 207-212.

DOI: 10.1016/j.jallcom.2019.05.001

[14] John F R. Effect of Alpha Chromium on Long Time Behavior of Alloy 718. Superalloys 718, 625, 706 and Various Derivatives. Pittsburgh, PA: TMS, 1997: 409-415.

DOI: 10.7449/1997/superalloys_1997_409_415

[15] Davuluri S, Mantha V S, Murthy G V S. Comprehensive Microstructural Evaluation of Precipitation in Inconel 718 [J]. Metallography, Microstructure, and Analysis, 2019, 8(2): 233-240.

DOI: 10.1007/s13632-018-00513-0

[16] Yu Z S, Zhang J X, Yuan Y, et al. Microstructural evolution, and mechanical properties of Inconel 718 after thermal exposure [J]. Materials Science and Engineering A, 2015, 634: 55-63.

DOI: 10.1016/j.msea.2015.03.004

[17] John F. Radavich, Korth G E. High Temperature Degradation of Alloy 718 After Long Time Exposure. Superalloys 1992. Seven Spring, PA: TMS, 1992. 497-597.

DOI: 10.7449/1992/superalloys_1992_497_505

[18] Wang G l, Wu C W, Zhang M C et al. The microstructural changes and their effect on CCGR after long time thermal exposure in DA718 and STD718 [J]. Materials Science and Engineering A. 2003, 358: 71-75.

DOI: 10.1016/s0921-5093(03)00245-4

[19] Zhao W, Dong J X, Zhang M C, Yao Z H. High-temperature microstructure stability of GH4169, GH4169plus and GH4738 alloy [J]. Transactions of Materials and Heat Treatment. 2015, 36(Supplement Ⅰ): 1-6.