Accelerated Homogenization of a Cast Nickel-Based Superalloy VDM780 via Thermomechanical Processing

Document Type : Research Paper

Authors

School of Metallurgy & Materials Engineering, Iran University of Science and Technology (IUST), Tehran, Iran

Abstract

In recent years, the push to reduce fuel consumption and emissions in turbines, designs have focused on achieving higher operating temperatures, which require materials capable of sustaining elevated temperatures in industrial applications. The development and production of the nickel-base superalloy VDM780, with an operating temperature above 750 °C (nominally 780 °C), have been pursued to meet this demand. This superalloy is often considered a suitable alternative to Inconel 718. The present study demonstrates the thermomechanical processing can significantly accelerate homogenization, enabling the production of a wrought structure in VDM780 with minimal heat treatment. A cast ingot of the VDM780 superalloy was first prepared using a vacuum induction melting (VIM) furnace, without employing refining processes such as electroslag remelting (ESR) or vacuum arc remelting (VAR). The conditions for homogenization and hot rolling were then investigated using simultaneous thermal analysis (STA). The results show that a homogenization temperature of 1160 °C provides adequate homogenization, resulting in a microstructure that is well-suited for workability.

Keywords

References

[1] Fedorova, T., Rösler, J., Klöwer, J., & Gehrmann, B. (2014). Development of a new 718-type Ni-Co superalloy family for high temperature applications at 750 °C. In MATEC Web of Conferences (Vol. 14, p. 01003). EDP Sciences. https://doi.org/10.1051/matecconf/20141401003
[2] Fedorova, T., Rösler, J., Gehrmann, B., & Klöwer, J. (2014, November). Invention of a new 718‐type Ni‐Co superalloy family for high temperature applications at 750 °C. In 8th International Symposium on Superalloy 718 and Derivatives (pp. 587-599). Hoboken, NJ, USA: John Wiley & Sons, Inc.. https://doi.org/10.1002/9781119016854.ch46
[3] Rösler, J., Hentrich, T., & Gehrmann, B. (2019). On the development concept for a new 718-type superalloy with improved temperature capability. Metals, 9(10), 1–20. https://doi.org/10.3390/met9101130
[4] Sharma, J., Nicolaÿ, A., De Graef, M., & Bozzolo, N. (2021). Phase discrimination between δ and η phases in the new nickel-based superalloy VDM Alloy 780 using EBSD. Materials Characterization, 176, 111105. https://doi.org/10.1016/j.matchar.2021.111105
[5] Ghica, C., Solís, C., Munke, J., Stark, A., Gehrmann, B., Bergner, M., Rösler, J., & Gilles, R. (2020). HRTEM analysis of the high-temperature phases of the newly developed high-temperature Ni-base superalloy VDM 780 premium. Journal of Alloys and Compounds, 814, 152157. https://doi.org/10.1016/j.jallcom.2019.152157
[6] Bergner, M., Rösler, J., Gehrmann, B., & Klöwer, J. (2018, May). Effect of heat treatment on microstructure and mechanical properties of VDM Alloy 780 premium. In Proceedings of the 9th International Symposium on Superalloy 718 & Derivatives: Energy, Aerospace, and Industrial Applications (pp. 489-499). Cham: Springer International Publishing. https://doi.org/10.1007/978-3-319-89480-5_31
[7] Gehrmann, B., Kloewer, J., Fedorova, T., & Roesler, J. (2015). Nickel-cobalt alloy (U.S. Patent Application No. US20150354031A1). United States Patent and Trademark Office. https://patents.google.com/patent/US20150354031A1
[8] Gehrmann, B., Hentrich, T., Schmidt, C., & Brunnert, K. (2021). Nickel-cobalt alloy powder and method of manufacturing the powder (German Patent Application No. DE102020116868A1). German Patent and Trademark Office. https://patents.google.com/patent/DE102020116868A1/en
[9] Solís, C., Munke, J., Bergner, M., Kriele, A., Mühlbauer, M. J., Cheptiakov, D. V., Gehrmann, B., Rösler, J., & Gilles, R. (2018). In situ characterization at elevated temperatures of a new Ni-based superalloy VDM-780 premium. Metallurgical and Materials Transactions A, 49(9), 4373–4381. https://doi.org/10.1007/s11661-018-4761-6
[10] Kümmel, F., Fritton, M., Solís, C., Kriele, A., Stark, A., & Gilles, R. (2022). Near-surface and bulk dissolution behavior of γ′ precipitates in nickel-based VDM® alloy 780 studied with in-situ lab-source and synchrotron X-ray diffraction. Metals, 12(7), 1067. https://doi.org/10.3390/met12071067
[11] Fritton, M., Nagel, O., Kümmel, F., Stark, A., Hafez Haghighat, M., Gehrmann, B., Neumeier, S, & Gilles, R. (2025). Post hot-deformation precipitation behavior of γ′ phase in VDM® alloy 780 under varying cooling rates and aging temperatures: An in situ high energy XRD study. Journal of Alloys and Compounds, 1037, 182111. https://doi.org/10.1016/j.jallcom.2025.182111
[12] Ariaseta, A., Sadeghinia, N., Andersson, J., & Ojo, O. (2023). Keyhole TIG welding of newly developed nickel-based superalloy VDM Alloy 780. Welding in the World, 67(1), 209–222. https://doi.org/10.1007/s40194-022-01425-y
[13] Solís, C., Kirchmayer, A., da Silva, I., Kümmel, F., Mühlbauer, S., Beran, P., Gehrmann, B., Hafez Haghighat, M., Neumeier, S., & Gilles, R. (2022). Monitoring the precipitation of the hardening phase in the new VDM® alloy 780 by in-situ high-temperature small-angle neutron scattering, neutron diffraction and complementary microscopy techniques. Journal of Alloys and Compounds, 928, 167203. https://doi.org/10.1016/j.jallcom.2022.167203
[14] Kirchmayer, A., Weiser, M., Randelzhofer, P., Freund, L. P., Gehrmann, B., Hafez Haghighat, M., Huenert, D., Göken, M., & Neumeier, S. (2023). Oxidation behavior of the polycrystalline Ni-base superalloy VDM® alloy 780. Metallurgical and Materials Transactions A, 54(5), 1961–1970. https://doi.org/10.1007/s11661-022-06956-z
[15] Kümmel, F., Kirchmayer, A., Solís, C., Hofmann, M., Neumeier, S., & Gilles, R. (2021). Deformation mechanisms in Ni-based superalloys at room and elevated temperatures studied by in situ neutron diffraction and electron microscopy. Metals, 11(5). https://doi.org/10.3390/met11050719
[16] Hou, K., Ou, M., Xing, W., Ma, G., Hao, X., Wang, M., & Ma, Y. (2024). The formation of η-Ni3Ti phase microstructure in a cast nickel-based superalloy with high Ti/Al ratio. Journal of Materials Research and Technology, 29, 764–778. https://doi.org/10.1016/j.jmrt.2024.01.156
[17] Hardy, M. C., Hafez Haghighat, M., Argyrakis, C., Buckingham, R. C., La Monaca, A., & Gehrmann, B. (2023, March). The effect of microstructure on the strength of VDM alloy 780. In TMS Annual Meeting & Exhibition (pp. 29-47). Cham: Springer Nature Switzerland.
[18] Vaasudevan, A., León-Cázares, F. D., Fischer, E., Witulski, T., Rae, C., & Galindo-Nava, E. (2023). Towards enhancing hot tooling to form high-γ′ superalloys. Minerals, Metals and Materials Series, 718, 65–91. https://doi.org/10.1007/978-3-031-27447-3_5
[19] Sharma, J., Hafez Haghighat, M., Gehrmann, B., Moussa, C., & Bozzolo, N. (2020, August). Dynamic and post-dynamic recrystallization during supersolvus forging of the new nickel-based superalloy—VDM alloy 780. In Superalloys 2020: Proceedings of the 14th International Symposium on Superalloys (pp. 450-460). Cham: Springer International Publishing. https://doi.org/10.1007/978-3-030-51834-9_44
[20] Hafez Haghighat, M., Sharma, J., Gehrmann, B., Alves, H., & Bozzolo, N. (2023). Supersolvus recrystallization and grain growth kinetics for the fine tuning of grain size in VDM alloy 780 forgings. Metallurgical and Materials Transactions A, 54(5), 2092–2111. https://doi.org/10.1007/s11661-023-07018-8
[21] Forbes Jones, R. M., & Jackman, L. A. (1999). The structural evolution of superalloy ingots during hot working. JOM, 51(1), 27–31. https://doi.org/10.1007/s11837-999-0007-9
[22] Raza, S. S., Ahmad, T., Kamran, M., Zhang, X., Basit, M. A., Manzoor, M. U., Inam, A., Butt, O. M., & Abrar, M. (2020). Effect of hot rolling on microstructures and mechanical properties of Ni base superalloy. Vacuum, 174, 109204. https://doi.org/10.1016/j.vacuum.2020.109204
[23] Błoniarz, R., Majta, J., Rutkowski, B., Korpała, G., Prahl, U., Janiszewski, J., & Lisiecka-Graca, P. (2021). How the thermomechanical processing can modify the high strain rate mechanical response of a microalloyed steel. Materials, 14(20), 1–17. https://doi.org/10.3390/ma14206062
[24] Wan, Z. P., Shen, J. Y., Wang, T., Wei, K., Li, Z., Yan, S., Liu, M., & Hu, L. X. (2022). Effect of hot deformation parameters on the dissolution of γ′ precipitates for as-cast Ni-based superalloys. Journal of Materials Engineering and Performance, 31(2), 1594–1606. https://doi.org/10.1007/s11665-021-06276-0
Iranian Journal of Materials Forming
Volume 12, Issue 3
2025
Pages 33-41

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