Grain structure simulation in a large-scale casting made of VZhL14N-VI nickel-base superalloy

The study addresses the problem of predicting the grain structure in large-scale castings made of the VZhL14N-VI nickel-base superalloy, which are bodies of revolution with very thin walls. To this end, the ProCast casting simulation software was used, including its CAFE module for grain structure prediction. Cooling rates in various areas of the casting were determined by computer simulation. Grain size measurements were then performed on real samples produced under industrial conditions at PJSC UEC Kuznetsov (Samara, Russia), and the correlation between grain size and cooling rate was established. It was found that grain size is affected not only by the cooling rate, but also by the geometric features of the casting, particularly its thermal modulus (according to Chvorinov’s rule). The results show that ProCast can be effectively used to predict casting defects in large-scale castings made of nickel-base superalloys. A comparison of the temperature-dependent density, specific heat capacity, and thermal conductivity of the VZhL14N-VI alloy – obtained through both direct measurements and ProCast thermodynamic database calculations – showed that the computed data are sufficiently accurate for use in casting process simulations. The CAFE module was found to be applicable for predicting grain structure in castings; however, accurate simulation requires the specification of key parameters, primarily the degree of undercooling during solidification and the number of grain nuclei in the alloy. Since these parameters cannot be measured directly, further research is required to determine them.

1. Логунов А.В., Шмотин Ю.Н. Современные жаропрочные никелевые сплавы для дисков газовых турбин (материалы и технологии). М.: Наука и технологии, 2013. 264 с.

2. Hassan B., Corney J. Grain boundary precipitation in Inconel 718 and ATI 718Plus. Materials Science and Technology. 2017;33(16):1879—1889. https://doi.org/10.1080/02670836.2017.1333222

3. Cemal M., Cevik S., Uzunonat Y., Diltemiz F. ALLVAC 718 Plus™ superalloy for aircraft engine applications. In: Recent Advances in Aircraft Technology. Agarwal R. (Ed.). 2012. Р. 75—96. https://doi.org/10.5772/38433

4. Kirchmayer A., Pröbstle M., Huenert D., Neumeier S., Göken M. Influence of grain size and volume fraction of η/δ precipitates on the dwell fatigue crack propagation rate and creep resistance of the nickel-base superalloy ATI 718Plus. Metallurgical and Materials Transactions: A. 2023;54:2219—2226. https://doi.org/10.1007/s11661-023-07001-3

5. Donachie M.J., Donachie S.J. Superalloys: A technical guide. 2nd ed. Materials Park, Ohio: ASM International, 2002. 408 р.

6. Chen Y.T., Yeh A.C., Li M.Y., Kuo, S.M. Effects of processing routes on room temperature tensile strength and elongation for Inconel 718. Materials & Design. 2017;119:235—243. https://doi.org/10.1016/j.matdes.2017.01.069

7. Geddes B., Leon H., Huang X. Superalloys: alloying and performance. Ohio, Materials Park: ASM International, 2010. 176 р.

8. Reed R.C. The superalloys: Fundamentals and applications. Cambridge: Cambridge University Press, 2006. 392 р.

9. Gadalov V.N., Vornacheva I.V., Pankov D.N., Bugorsky I.A., Zagidullin R.R., Sabitov L.S., Ivanov A.A. Study of the influence of the structure of nickelchromium superalloys on their mechanical properties. Izvestiya Tul’skogo gosudarstvennogo universiteta. Tekhnicheskie nauki. 2022;10:463—471. (In. Russ.). https://doi.org/10.24412/2071-6168-2022-10-463-471

10. Lv J. Effect of grain size on mechanical property and corrosion resistance of the Ni-based alloy 690. Journal of Materials Science & Technology. 2018;34:1685—1691. https://doi.org/10.1016/j.jmst.2017.12.017

11. Cantor B., O’Reilly K. Solidification and casting. 1st ed. CRC Press. 2002. 428 р. https://doi.org/10.1201/9781420033502

12. Пикунов М.В. Плавка металлов. Кристаллизация сплавов. Затвердевание отливок. М.: МИСИС, 2005. 416 с.

13. Nikitina A.A., Bazhenov V.E., Koltygin A.V., Belov V.D. Effect of the temperature of the shell ceramic mold before pouring and the pouring temperature on defects in the casting “inner body of the combustion chamber” from nickel heat-resistant alloy VZhL14N-VI. Tsvetnyye metally. 2024;1:79—85. (In. Russ.). https://doi.org/10.17580/tsm.2024.01.10

14. Gandin Ch.A., Rappaz M.A. 3D Cellular automaton algorithm for the prediction of dendritic grain growth. Acta Materialia. 1997;45(5):2187—2195. https://doi.org/10.1016/S1359-6454(96)00303-5

15. Rappaz M., Gandin Ch.A. Probabilistic modelling of microstructure formation in solidification processes. Acta Metallurgica et Materialia. 1993;41(2):3450—3460. https://doi.org/10.1016/0956-7151(93)90065-Z

16. Kavoosi V., Abbasi S.M., Mirsaed S.M. Ghazi, Mostafaei M. Influence of cooling rate on the solidification behavior and microstructure of IN738LC superalloy. Journal of Alloys and Compounds. 2016;680:291—300. http://dx.doi.org/10.1016/j.jallcom.2016.04.099

17. Беккерт М., Клемм Х. Способы металлографического травления: Справ. изд.: Пер. с нем. 2-е изд., перераб. и доп. М.: Металлургия. 1988. 400 с.

18. Bazhenov V.E., Koltygin A.V., Fadeev A.V. The use of the ProCast software to simulate the process of investment casting of alloy based on titanium aluminide TNM-B1 into ceramic molds. Russian Journal of Non-Ferrous Metals. 2014;55(1):15—19. https://doi.org/10.3103/S1067821214010039

19. Yu J., Wang D., Li D., Tang D., Zhu G., Dong A., Shu D., Peng Y. Process parameter effects on solidification behavior of the superalloy during investment casting. Materials and Manufacturing Processes. 2019;34(15):1726—1736. https://doi.org/10.1080/10426914.2019.1666989

20. Guo J., Beckermann C., Carlson K., Hirvo D., Bell K., Moreland T., Gu J., Clews J., Scott S., Couturier G., Backman D. Microporosity prediction and validation for Nibased superalloy castings. IOP Conference Series: Materials Science and Engineering. 2015;84:012003. https://doi.org/10.1088/1757-899X/84/1/012003

21. Xu M., Lekakh S.N., Richards V.L. Thermal property database for investment casting shells. International Journal of Metalcasting. 2016;10(3):329—337. https://doi.org/10.1007/s40962-016-0052-4

22. Torroba A.J., Koeser O., Calba L., Maestro L., Carreño-Morelli E., Rahimian M., Milenkovic S., Sabirov I., LLorca J. Investment casting of nozzle guide vanes from nickel-based superalloys: Part I. Thermal calibration and porosity prediction. Integrating Materials and Manufacturing Innovation. 2014;3(1):344—368. https://doi.org/10.1186/s40192-014-0025-5

23. Szeliga D., Kubiak K., Burbelko A.A., Cygan R., Ziaja W. Modelling of grain microstructure of IN-713C castings. Solid State Phenomena. 2013;197:83—88. https://doi.org/10.4028/www.scientific.net/SSP.197.83

24. Kermanpur A., Rappaz M., Varahram N., Davami P. Thermal and grain-structure simulation in a land-based turbine blade directionally solidified with the liquid metal cooling process. Metallurgical and Materials Transactions B. 2000;31(6):1293—1304. https://doi.org/10.1007/s11663-000-0017-z

25. Dantzig J.A., Rappaz M. Solidification: Revised & Expanded. EPFL press, 2016. 700 р.