Abstract
Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermodynamic calculations were employed to study the phase stability and phase precipitation in the Ni-based superalloy Nimonic 263. The major precipitates at temperatures below 900 °C were gamma-prime and eta (Ni3Ti), with the eta phase starting to precipitate at the expense of the gamma-prime phase after prolonged annealing. The eta precipitates had a thin-plate morphology and formed a regular Widmanstätten pattern. They had a fixed orientation relationship with the fcc matrix. Very fine particles of M23C6 also precipitated intragranularly, and they had a cube-on-cube orientation relationship (OR) with the fcc matrix. Intragranular precipitation of a very fine cylindrical MC carbide was also observed. Grain-boundary (GB) precipitates were mostly M23C6, with a small fraction of MC. Based on the experimental results, a time-temperature-transformation (TTT) diagram was constructed. The experimental results were compared to thermodynamic predictions, and good agreement was observed. The calculations correctly predicted almost all the major phases and their stability temperature ranges. The experimental and calculation results, together, depict a clearer picture of phase stability in the alloy.
Similar content being viewed by others
References
Alloy Digest, Ni-350, Alloy Digest, Inc., Orange, NJ, July 1987.
B. Hicks and M. Heap: Report No. B48749, Lucas Gas Turbine Equipment Ltd., Materials Laboratory, Burnley, Sept. 25, 1968.
V. Ratna and D.S. Sarma: Scripta Metall. Mater., 1993, vol. 29, pp. 467–72.
G.F. Vander Voort and H.M. James: ASM Handbook, vol. 9, Metallography and Microstructures, ASM INTERNATIONAL, Metals Park, OH, 1985, pp. 305–29.
P. Villars and L.D. Calvert: Pearsons Handbook of Crystallographic Data for Intermetallic Phases, 2nd ed., ASM INTERNATIONAL, Materials Park, OH, 1991, vols. 1–4.
P.N. Singh and V. Singh: Scripta Mater., 1996, vol. 34, pp. 1861–65.
B. Sundman, B. Jansson, and J.O. Anderson: CALPHAD, 1985, vol. 9, pp. 153–90.
NiFe-Data, Version 2, Thermo-Tech Ltd., Surrey, United Kingdom, 1998.
H.P. Merrick and R.B. Nicholson: 5th Int. Congr. for Electron Microscopy, Academic Press, New York, NY, 1962, paper no. K-8.
R.G. Baker, D.G. Brandon, and J. Nutting: Phil. Mag., 1959, vol. 4, pp. 1339–45.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Zhao, J.C., Ravikumar, V. & Beltran, A.M. Phase precipitation and phase stability in nimonic 263. Metall Mater Trans A 32, 1271–1282 (2001). https://doi.org/10.1007/s11661-001-0217-4
Received:
Issue Date:
DOI: https://doi.org/10.1007/s11661-001-0217-4