Abstract
The effect of orientation on the primary-creep mechanism of the Ni-based single-crystal superalloy CMSX-4 is examined. Four specimens with orientations within 20 deg of the [001] axis are deformed at 750 °C and 750 MPa and show a decreasing amount of primary creep as the tensile axis approaches the [001]–[011] symmetry boundary. Of these, specimen N lies within 1 deg of [013] and shows a negligible primary creep and a very low secondary creep rate. For this specimen, direct observation in the transmission electron microscope (TEM) and analysis of the shape change show that 〈112〉{111}, stacking-fault shear, is absent. Analysis of the dislocations present in the gamma precipitates and at the γ/γ′ interface shows that the only dislocations present have the Burgers vectors a/2[101] and a/2[10-1], which cannot combine to nucleate the dislocations necessary for stacking-fault shear. Thus, it is argued that the reason for the low degree of primary creep for orientations close to the [001]–[011] symmetry boundary is not the interaction between two equally stressed 〈112〉{111} systems, but the lack of either. As the orientation moves away from the [001]–[011] boundary, the range of dislocation Burgers vectors increases and stacking-fault shear is nucleated; the amount of primary creep increases as a consequence.
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Superalloys II, C.T. Sims N.S. Stoloff, and W.C. Hagel, eds., John Wiley, New York, NY, 1988.
W. Betteridge and S.W.K. Shaw: Mater. Sci. Technol., 1987, vol. 3, pp. 682–94.
R.A. MacKay and R.D. Maier: Metall. Trans. A, 1982, vol. 13A, pp. 1747–54.
F.R.N. Nabarro and H.L. Villiers: The Physics of Creep, Taylor and Francis, London, 1995, pp. 217–21.
N. Matan, D.C. Cox, P. Carter, M.A. Rist, C.M.F. Rae, and R.C. Reed: Acta Mater., 1999, vol. 47(5), pp. 1549–63.
A.A. Hopgood and J.W. Martin: Mater: Sci. Eng., 1986, vol. 82, pp. 27–36.
N. Matan: Ph.D. Thesis, Cambridge University, Cambridge, United Kingdom, 1999.
G.R. Leverant, B.H. Kear, and J.M. Oblak: Metall. Trans., 1973, vol. 4, pp. 355–62.
G.R. Leverant and B.H. Kear: Metall. Trans., 1970, vol. 1, pp. 491–98.
P. Caron, Y. Ohta, Y.G. Nakagawa, and T. Khan: in Superalloys 1988, S. Reichman, D.N. Duhl, G. Maurer, S. Antonlovich, and C. Lund, eds., TMS-AIME, Warrendale, PA, 1988, pp. 215–24.
H. Murakami, T. Yamagata, H. Harada, and M. Yamazaki: Mater. Sci. Eng., 1997, vol. A223, pp. 54–58.
T. Link and M. Feller-Kniepmeier: Metall. Trans. A, 1992, vol. 23A, pp. 99–105.
M. Feller-Kniepmeier and T. Kuttner: Acta Mater., 1994, vol. 42 (9), pp. 3167–74.
R.N. Ghosh, R.V. Curtis, and M. McLean: Acta Mater., 1990, vol. 38 (10), pp. 1977–92.
L.M. Pan, B.A. Shollock, and M. McLean: Proc. R. Soc. London. 1997, vol. 453A, p. 1689.
L.M. Pan, I. Scheibli, M.B. Henderson, B.A. Shollock, and M. McLean: Acta Mater., 1995, vol. 43, pp. 1375–84.
M.G. Ardakani, R.N. Ghosh, V Brien, B.A. Shollock, and M. McLean: Scripta Mater., 1998, vol. 39, p. 465.
British Standard UDC 629.7, The British Standards Institution, London, 1965.
M.J. Goulette, P.D. Spilling, and R.P. Arthey: in Superalloys 1984, M. Gell, C.S. Kortovich, R.M. Bricknell, W.B. Kent, J.F. Radavich. TMS-AIME, Warrendale, PA, 1984, pp. 167–76.
B.L. Adams, S.I. Wright, and K. Kunze: Metall. Trans. A, 1993, vol. 24A, pp. 819–31.
S.I. Wright, J. Zhao, and B.L. Adams: Text. Microstr., 1991, vol. 13, pp. 123–31.
S.I. Wright and B.L. Adams: Text. Microstr., 1991, vol. 14, pp. 273–78.
C.M.F. Rae, N. Matan, and R.C. Reed: Cambridge University, Cambridge, United Kingdom, [unpublished work], 1999.
V. Sass, U. Glatzel, and M. Feller-Kniepmeier: Acta Mater., 1996, vol. 44(5), pp. 196–77.
V. Sass and M. Feller-Kniepmeier: Mater. Sci. Eng., 1998, vol. A245, pp. 19–28.
K. Kakechi: Mater. Sci. Eng., 2000, vol. A278, 135–41.
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Rae, C.M.F., Rist, M.A., Cox, D.C. et al. On the primary creep of CMSX-4 superalloy single crystals. Metall Mater Trans A 31, 2219–2228 (2000). https://doi.org/10.1007/s11661-000-0139-6
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DOI: https://doi.org/10.1007/s11661-000-0139-6