Abstract
Carbon is added to large single-crystal nickel-based superalloy components to reduce grain defects. In this study, the effect of carbon additions on the microstructure of a model nickel-based superalloy, LMSX-1, was examined. Previous results have shown that as carbon content increased, the tendency of the alloy to form all types of solidification defects decreased. In addition, as the carbon content increased, the as-cast microstructures exhibited a decrease in the amount of γ-γ′ eutectic structure and an increase in the volume fraction of carbides and porosity. The carbides formed in these alloys were mostly script-type MC carbides which formed continuous, dendritic networks in the interdendritic region. Microprobe analysis of the as-cast structures showed that the partitioning coefficients did not change with carbon additions. Therefore, the reduction in defect formation with increasing carbon content could not be attributed to changes in segregation behavior of alloying elements. Instead, the presence of these carbides in the interdendritic regions of the alloy appeared to have prevented the thermosolutal fluid flow.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
C.T. Sims, N.S. Stoloff, and W.C. Hagel, editors, Superalloys II (New York: John Wiley & Sons, Inc., 1987).
A.F. Giamei and B.H. Kear, “On the Nature of Freckles in Nickel Base Superalloys,” Metallurgical Transactions, 1 (1970), pp. 2185–2192.
S. Tin, T.M. Pollock, and W.T. King, “Carbon Additions and Grain Defect Formation in High Refractory Nickel-Base Single Crystal Superalloys,” Superalloys 2000, ed. T.M. Pollock et al. (Warrendale, PA: TMS, 2000), pp. 201–210.
S. Tin, “Carbon Additions and Grain Defects Formation in Directionally Solidified Nickel-Base Superalloys,” (Pd.D. thesis, University of Michigan, 2001).
J.R. Mihalisin et al., “Casting of Single Crystal Superalloy Articles with Reduced Eutectic Scale and Grain Recrystallization,” U.S. patent application US2002/0007877 (January 2002).
W.R. Sun et al., “The Eutectic Characteristics of MC-type Carbide Precipitation in DS Nickel-Base Superalloy,” Materials Science & Engineering, A271 (1999), pp. 143–149.
S.M. Copley et al., “The Origin of Freckles in Unidirectionally Solidified Castings.” Metallurgical Transactions, 1 (1970), pp. 2193–2204.
T.M. Pollock et al., “Grain Defect Formation during Directional Solidification of Nickel Base Single Crystals,” Superalloys 1992, ed. S.D. Antolovich et al. (Warrendale, PA: TMS, 1992), pp. 125–134.
R. Fernandez, J.C. Lecomte, and T.Z. Kattamis, “Effect of Solidification Parameters on the Growth Geometry of MC Carbide in IN-100 Dendritic Monocrystals,” Metallurgical Transactions A, 9A (1978), pp. 1381–1386.
M.N. Gungor, “A Statistically Significant Experimental Technique for Investigating Microsegregation in Cast Alloys,” Metallurgical Transactions A, 20A (1989), pp. 2529–2533.
S.C. Huang, L. Peluso, and D. Backman, “Measurements of Solute Segregation Coefficients in Quaternary Ni-Based Superalloys,” Solidification 1999, ed. W.H. Hofmeister et al. (Warrendale, PA: TMS, 1999), pp. 163–172.
J.I. Goldstein et al., Scanning Electron Microscopy and X-Ray Microanalysis, second edition (New York: Plenum Press, 1992).
T.M. Pollock, “The Growth and Elevated Temperature Stability of High Refractory Nickel-base Single Crystals,” Materials Science & Engineering, B32 (1995), pp. 255–266.
T.M. Pollock and W.H. Murphy, “The Breakdown of Single Crystal Solidification in High Refractory Nickel-Base Alloys,” Metallurgical and Materials Transactions A, 27A (1996), pp. 1081–1094.
P. Auburtin, S.L. Cockcroft, and A. Mitchell, “Liquid Density Inversions during the Solidification of Superalloys and their Relationship to Freckle Formation in Castings,” Superalloys 1996, ed. R.D. Kissinger et al. (Warrendale, PA: TMS, 1996), pp. 443–447.
M.C. Schneider et al., “Modeling of Micro- and Macrosegregation and Freckle Formation in Single Crystal Nickel-Base Superalloy Directional Solidification,” Metallurgical and Materials Transactions A, 28A (1997), pp. 1517–1531.
Author information
Authors and Affiliations
Additional information
For more information, contact G.E. Fuchs, University of Florida, Materials Science and Engineering Department, P.O. Box 116400, Gainesville, FL 32611-6400; (352) 846-3317; fax (352) 392-7219; e-mail gfuch@mse.ufl.edu.
Rights and permissions
About this article
Cite this article
Al-Jarba, K.A., Fuchs, G.E. Carbon-containing single-crystal nickel-based superalloys: Segregation behavior and carbide formation. JOM 56, 50–55 (2004). https://doi.org/10.1007/s11837-004-0201-8
Issue Date:
DOI: https://doi.org/10.1007/s11837-004-0201-8