Abstract
Ni-base superalloys contain beside other phases relatively large blocky MC carbides of the type (Ta, Nb, Ti, W)C, which oxidize much faster than the γ/γ′ matrix. The large volume increase during oxidation and the oxide formation at the carbide-oxide interface shift the corrosion products outward. High shear stresses between the Cr2O3 scale and the carbide oxidation products lead to scale cracking favoring internal corrosion processes in this area. The formation of Al2O3 in the subscale is accompanied by a volume increase and tensile stresses in the outer Cr2O3 scale. This causes scale cracking and gives nitrogen a chance to enter the metal and form the most stable nitride, TiN beneath the Al2O3 subscale.
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References
G. E. Wasielewski and R. A. Rapp, inThe Superalloys, C. T. Sims and W. C. Hagel, eds. (Wiley, New York, 1972), p. 287.
H. J. Christ, L. Berchtold, and H. G. Sockel,Oxid. Met. 26, 45 (1986).
C. A. Barrett, G. J. Santoro, and C. E. Lowell, NASA TN D-7484 (1973).
C. A. Barrett, J. R. Johnston, and W. A. Sanders,Oxid. Met. 12, 343 (1978).
C. A. Barrett, R. V. Miner, and D. R. Hull,Oxid. Met. 20, 255 (1983).
F. Abe, H. Araki, H. Yoshida, and M. Okada,Oxid. Met. 27, 21 (1987).
S. Guriswamy, S. M. Park, J. P. Hirth, and R. A. Rapp,Oxid. Met. 26, 77 (1986).
M. Schütze,Oxid. Met. 24, 265 (1985).
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Litz, J., Rahmel, A. & Schorr, M. Selective carbide oxidation and internal nitridation of the Ni-base superalloys IN 738 LC and IN 939 in air. Oxid Met 30, 95–105 (1988). https://doi.org/10.1007/BF00656646
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DOI: https://doi.org/10.1007/BF00656646