Effect of Zr on solidification and microstructure of a Ni-based superalloy with high Al and Ti contents

Guang-di Zhao, Xi-min Zang, Fang Liu, Wei-wei Zhang, Shuo Gao, Xue Li, Jing Guo

China Foundry ›› 2022, Vol. 19 ›› Issue (1) : 17-26.

PDF(6747 KB)
PDF(6747 KB)
China Foundry ›› 2022, Vol. 19 ›› Issue (1) : 17-26. DOI: 10.1007/s41230-022-1058-6
Research & Development

Effect of Zr on solidification and microstructure of a Ni-based superalloy with high Al and Ti contents

  • Guang-di Zhao1, Xi-min Zang1, Fang Liu2, Wei-wei Zhang2, Shuo Gao1, Xue Li1, Jing Guo1
Author information +
History +

Abstract

The total content of Al and Ti in advanced Ni-based wrought superalloys is up to 7.5wt.%, which makes it easier to form harmful nonequilibrium eutectic (γ+γ') and η phase. It has been reported that the addition of certain amount of Zr can modify precipitation of the nonequilibrium phases obviously, but the mechanism is still controversial. The effect of Zr ranging from <0.0006wt.% to 0.150wt.% on solidification behavior, segregation and microstructure of a Ni-based superalloy with high Al and Ti contents was investigated, eliminating the interferences of C and B. Results show that increase in Zr content significantly promotes the formation of eutectic (γ+γ'), η and Zr-rich phase in the interdendritic region. Besides the Zr-rich phase, Zr dissolves slightly in the eutectic γ' and obviously in the η phase. An interesting phenomenon is discovered that the Zr addition significantly increases the area fraction of liquid pools and enlarges the forming range of γ dendrites, which suggests that Zr markedly retards the solidification. Zr affects the eutectic (γ+γ') and η formation mainly due to the retard of solidification and dissolution of Zr in them. The retard of solidification obviously increases the residual liquid fraction and undercooling. Zr can serve as a forming element for the eutectic (γ+γ') and η phase, and the obvious dissolution of Zr in η phase significantly decreases the critical concentration of Ti for its precipitation.

Key words

zirconium / Ni-based superalloy / solidification behavior / segregation

Cite this article

Download Citations
Guang-di Zhao, Xi-min Zang, Fang Liu, Wei-wei Zhang, Shuo Gao, Xue Li, Jing Guo. Effect of Zr on solidification and microstructure of a Ni-based superalloy with high Al and Ti contents[J]. China Foundry, 2022, 19(1): 17-26 https://doi.org/10.1007/s41230-022-1058-6

References

[1] Reed R C. The superalloys: Fundamentals and applications. New York: Cambridge University Press, 2008.
[2] Pu Y L, Kou S Z, Zhang Z D, et al. Effects of returns on composition, microstructure and mechanical properties of GH4169 superalloy. China Foundry, 2017, 14(4): 244–250.
[3] Kim S E, Jackson M P, Reed R C, et al. Quantification of the minor precipitates in UDIMETTM alloy 720(Li) using electrolytic extraction and X-ray diffraction. Materials Science and Engineering: A, 1998, 245(2): 225–232.
[4] Monajati H, Taheri A K, Jahazi M, et al. Deformation characteristics of isothermally forged UDIMET 720 nickel-base superalloy. Metallurgical and Materials Transactions A, 2005, 36: 895–905.
[5] Zhao G D, Yu L X, Yang G L, et al. The role of boron in modifying the solidification and microstructure of nickel-base alloy U720Li. Journal of Alloys and Compounds, 2016, 686: 194–203.
[6] Chang L T, Jin H, Sun W R. Solidification behavior of Ni-base superalloy udimet 720Li. Journal of Alloys and Compounds, 2015, 653: 266–270.
[7] Keefe P W, Mancuso S O, Maurer G E. Effects of heat treatment and chemistry on the long-term phase stability of a high strength nickel-based superalloy. Superalloys, 1992: 487–496.
[8] Helm D, Roder O. Influence of long term exposure in air on microstructure, surface stability and mechanical properties of udimet 720Li. Superalloys, 2000: 487–493.
[9] Zhao G D, Liu F, Zang X M, et al. Microstructure and hot ductility behavior of Ni-based superalloy U720Li with boron addition. Rare Metals, 2021, 40(5): 1145–1154.
[10] Zhang J, Singer R F. Effect of Zr and B on castability of Ni-based superalloy IN792. Metallurgical and Materials Transactions A, 2004, 35: 1337–1342.
[11] Sun W R, Zhao G D, Yu L X, et al. Homogenization process of superalloy U720Li, CN: ZL 201610459197.4, 2016. (In Chinese)
[12] Zhao G D, Zang X M, Qi F. Effect of boron on isothermal oxidation behavior of a nickel-base superalloy with high Al and Ti contents. Journal of Alloys and Compounds, 2020, 846: 156490.
[13] Couturier R, Burlet H, Terzi S, et al. Process development and mechanical properties of alloy U720Li for high temperature turbine disks. In: Proc. International Symposium on Superalloys, 2004: 351–359.doi:10.7449/2004/Superalloys_2004_351_359.
[14] Fecht H, Furrer D. Processing of nickel-base superalloys for turbine engine disc applications. Advanced Engineering Materials, 2000, 2(12): 777–787.
[15] Seo S M, Lee J H, Yoo Y S, et al. A comparative study of the γ/γ' eutectic evolution during the solidification of Ni-base superalloys. Metallurgical and Materials Transactions A, 2011, 42: 3150–3159.
[16] Zhang X Y, Liu L, Huang T W, et al. Effect of solidification parameters on the segregation and γ/γ' eutectic evolution in Ni-based single crystal superalloy DD6. Rare Metal Materials and Engineering, 2013, 42: 2547–2552.
[17] Liu L, Huang T W, Zhang J, et al. Microstructure and stress rupture properties of single crystal superalloy CMSX-2 under high thermal gradient directional solidification. Materials Letters, 2007, 61(1): 227–230.
[18] Zhang H, Pei Y, Li S, et al. Effect of process parameters on microstructures and properties of DZ125 superalloy solidified by LMC. Materials Research Innovations, 2014, 18: 385–389.
[19] Li Y M, Liu H J, Liu J, et al. Effect of Zr addition on precipitates in K4169 superalloy. China Foundry, 2012, 9(1): 6–10.
[20] Garosshen T J, Tillman T D, McCarthy G P. Effects of B, C, and Zr on the structure and properties of a P/M nickel-base superalloy. Metallurgical Transactions A, 1987, 18: 69–77.
[21] Huang H E, Koo C H. Effect of zirconium on microstructure and mechanical properties of cast fine-grain CM 247 LC superalloy. Materials Transactions, 2004, 45(2): 554–561.
[22] Zhou P J, Yu J J, Sun X F, et al. Roles of Zr and Y in cast microstructure of M951 nickel-based superalloy. Transactions of Nonferrous Metals Society of China, 2012, 22: 1594–1598.
[23] Wei C N, Bor H Y, Chang L. The effects of carbon content on the microstructure and elevated temperature tensile strength of a nickel-base superalloy. Materials Science and Engineering: A, 2010, 527: 3741–3747.
[24] Al-Jarba K A, Fuchs G E. Effect of carbon additions on the as-cast microstructure and defect formation of a single crystal Ni-based superalloy. Materials Science and Engineering: A, 2004, 373(1–2): 255–267.
[25] Liu L R, Jin T, Zhao N R, et al. Effect of carbon additions on the microstructure in a Ni-base single crystal superalloy. Materials Letters, 2004, 58(17–18): 2290–2294.
[26] Heydari D, Shahkaram F A, Bakhshi A, et al. Hot tearing in polycrystalline Ni-based IN738LC superalloy: Influence of Zr content. Journal of Materials Processing Technology, 2014, 214(3): 681–687.
[27] Yan B C, Zhang J, Lou L H. Effect of boron additions on the microstructure and transverse properties of a directionally solidified superalloy. Materials Science and Engineering: A, 2008, 474(1–2): 39–47.
[28] Hu Q, Liu L, Zhao X B, et al. Effect of carbon and boron additions on segregation behavior of directionally solidified nickel-base superalloys with rhenium. Transactions of Nonferrous Metals Society of China, 2013, 23(11): 3257–3264.
[29] Zhao G D, Zang X M, Sun W R. Role of carbon in modifying solidification and microstructure of a Ni-based superalloy with high Al and Ti contents. Journal of Iron and Steel Research International, 2021, 28: 98–110.
[30] Qi F, Yu L X, Zhao G D, et al. Effect of Zr on solidification segregation behavior of K417G alloy and its anomalous effect during rapid cooling process. Journal of Alloys and Compounds, 2020, 835(6): 155243.
[31] Tsai Y L, Wang S F, Bor H Y, et al. Effects of Zr addition on the microstructure and mechanical behavior of a fine-grained nickel-based superalloy at elevated temperatures. Materials Science and Engineering: A, 2014, 607: 294–301.
[32] Voort G. Metallography: Principles and practice. McGraw-Hill, 1984.
[33] 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. Materials Science and Engineering: A, 2005, 36: 2761–2773.
[34] Zhao G D, Yu L X, Qi F, et al. The minor precipitation at the final stage of U720Li solidification. Acta Metallurgica Sinica (English Letters), 2016, 29: 518–526.
[35] Zhao G D, Yang G L, Liu F, et al. Transformation mechanism of (γ+γ') and the effect of cooling rate on the final solidification of U720Li alloy. Acta Metallurgica Sinica, 2017, 30: 887–894.
[36] Mostafaei M, Abbasi S M. Influence of Zr content on the incipient melting behavior and stress-rupture life of CM247 LC nickel base superalloy. Journal of Alloys and Compounds, 2015, 648: 1031–1037.
[37] Herlach D M. Non-equilibrium solidification of undercooled metallic metls. Materials Science and Engineering: Reports, 1994,12(4–5): 177–272.
[38] Christian J W. The theory of transformations in metals and alloys. 1965.
[39] Grodzki J, Hartmann N, Rettig R, et al. Effect of B, Zr, and C on hot tearing of a directionally solidified Nickel-based superalloy. Metallurgical and Materials Transactions A, 2016, 47(6): 2914–2926.
[40] Holt R T, Wallace W. Impurities and trace elements in nickel-base superalloys. Int. Met. Rev., 1976, 21: 1–24.
[41] Doherty J E, Kea B H, Giamei A F. On the origin of the ductility enhancement in Hf-doped Mar-M200. The Journal of the Minerals, Metals and Materials Society, 1971, 23(11): 59–62.
[42] Rappaz M, Jacot A, Boettinger W J. Last-stage solidification of alloys: Theoretical model of dendrite-arm and grain coalescence. Metallurgical and Materials Transactions A, 2003, 34: 467–479.
[43] Keene J B. Review of data for the surface tension of pure metals. Metallurgical Reviews, 1993, 38: 157–192.
[44] McLean D. Grain boundaries in metals. Oxford: Clarendon Press, 1957.
[45] Gozlan E, Bamberger M, Dirnfeld S F, et al. Role of zirconium in the phase formation at the interdendritic zone in nickelbased superalloys. Journal of Materials Science, 1992, 27: 3869–3875.
[46] Decker R F, Freeman J W. The mechanism of beneficial effects of boron and zirconium on creep properties of a complex heat-resistant alloy. Technical Report Archive and Image Library, 1960, 218: 277–285.
[47] Seah M P. Adsorption-induced interface decohesion. Acta Metallurgica, 1980, 28(7): 955–962.

Funding

This work was financially supported by the National Natural Science Foundation of China (Grant No. 51904146).
PDF(6747 KB)

135

Accesses

0

Citation

Detail

Sections
Recommended

/