Abstract
New cobalt-based alloys containing ordered L12 precipitates have been investigated. With additions of Cr, Mo, Ni, Re, Ta, and V to the ternary Co-Al-W system, two phase γ-γ′ microstructures have been established. Solidus and liquidus temperatures are 100°C–150°C higher than advanced nickel-based single-crystal alloys strengthened with the L12 phase. An anomalous rise in flow stress with temperature is observed. Single crystals have been solidified and partitioning during solidification is limited in the ternary system, suggesting a high resistance to convective instabilities. Oxidation at 900°C results in the formation of cobalt oxide. Following oxidation, an inner layer of Al2O3 is observed in uncoated Cr-containing alloys and Cr2O3 is observed in alloys subjected to chromization.
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References
J. Sato et al., Science, 312 (2006), pp. 90–91.
A. Suzuki and T.M. Pollock, Acta Materialia, 56(6) (2008), pp. 1286–1297.
A. Suzuki, G.C. DeNolf, and T.M. Pollock, Scripta Materialia, 56 (2007), pp. 385–388.
C.T. Sims, N.S. Stoloff, and W.C. Hagel, Superalloys II (New York: John Wiley and Sons, 1986).
R.C. Reed, The Superalloys: Fundamentals and Applications (New York: Cambridge University Press, 2006).
T.M. Pollock and S. Tin, AIAA J. Propulsion and Power, 22(2) (2006), pp. 361–374.
M.N. Gungor, Metall. Trans., 20A (1989), pp. 2529–2533.
S.C. Huang, L. Peluso, and D. Backman, Solidification 1999, ed. W.H. Hofmeisteret al. (Warrendale, PA: TMS, 1999), pp. 163–172.
S. Tin, T.M. Pollock, and W. Murphy, Metall. Mater. Trans., 32A (2001), pp. 1743–1753.
T.M. Pollock and R.D. Field, Dislocations in Solids, Vol 11, ed. F.R.N. Nabarro and M.S. Duesbery (Amsterdam: Elsevier, 2002), pp. 548–618.
W.S. Walston et al., Superalloys 1996, ed. R.D. Kissinger et al. (Warrendale, PA TMS, 1996), pp. 9–18.
R. Schafrik and R. Sprague, Advanced Materials & Processes, 5 (2004), pp. 29–34.
S. Tin and T.M. Pollock, Journal of Materials Science, 39 (2004), pp. 7199–7205.
C. Beckermann, J.P. Gu, and W.J. Boettinger, Metall. Mater. Trans., 31A (2000), pp. 2545–2557.
T.M. Pollock and W.H. Murphy, Metall. Mater. Trans., 27A (1996), pp. 1081–1094.
R Auburtin, S.L. Cockcroft, and A. Mitchell, Superalloys 1996, ed. R.D. Kissinger et al. (Warrendale, RH: TMS, 1996), pp. 443–450.
J.R. Sarazin and A. Hellawell, Metall. Trans., 19A (1988), pp. 1861–1871.
G.R. Leverant and B.H. Kear, Metall. Trans., 1A (1970), pp. 491–498.
B.H. Kear, J.M. Oblak, and A.F. Giamei, Metall. Trans., (1970), pp. 2477–2487.
A.J. Huis in’t Veld et al., Sa Metall., 19 (1985), pp. 1123–1128.
B.H. Kear and H.G.F. Wilsdorf, Trans. AIME, 224 (1962), pp. 382–391.
D.R Pope and S.S. Ezz, Int’l. Mat. Rev., 29 (1984), pp. 136–167.
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Pollock, T.M., Dibbern, J., Tsunekane, M. et al. New Co-based γ-γ′ high-temperature alloys. JOM 62, 58–63 (2010). https://doi.org/10.1007/s11837-010-0013-y
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DOI: https://doi.org/10.1007/s11837-010-0013-y