Abstract
Transmission electron microscopy and diffraction were used to characterize the microstructural changes which occur in Hastelloy alloy X after long-term ageing (up to 16 000 h) at various temperatures in the range 540 to 870° C. The corresponding effects on mechanical properties were determined. It was found that the alloy age hardens at temperatures in the range of 650 to 870° C. Overageing occurred at 760 and 870° C. Marked reductions in room-temperature tensile elongation were observed after ageing at all the temperatures investigated. However, in no case was the elongation reduced to less than 15 to 30%. Also, the tensile elongation at temperatures corresponding to the respective ageing temperatures was unaffected by 16 000 h ageing at a temperature. It was concluded that the above effects were associated with precipitation of various phases, such as carbides, sigma- and mu-phases, in the matrix and at the grain boundaries.
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References
G. Y. Lai,Met. Trans. 9A (1978) 827.
S. J. Matthews, in Proceedings of the 3rd International Conference on Superalloys, Seven Springs, September 1976, edited by B. H. Kear, D. R. Muzka, J. K. Tien and S. T. Wlodek (Claitor's Publishing Division, Baton Rouge, 1976) p. 215.
P. S. Kotval,Metallography 1 (1969) 251.
J. W. Edington, “Typical Electron Microscope Investigations” (N. V. Philips, Gloeilampenfabrieken Eindhoren, 1976) p. 38.
H. M. Tawancy,J. Mater. Sci. 16 (1981) 1117.
J. M. Leitnaker, G. A. Potter, D. J. Bradly, J. C. Franklin andW. R. Laing,Met. Trans. 9A (1978) 397.
A. C. Fracker andH. H. Stadelamair,Trans. AIME 245 (1969) 857.
G. Wallwork andJ. Croll, “Review of High-Temperature Materials”, (Freund Publishing House, Ltd., Israel, 1976) p. 89.
F. C. Frank andJ. S. Kasper,Acta Crystallogr. 12 (1959) 483.
M. J. Marcinkowski andD. S. Miller,Phil. Mag. 7 (1962) 1025.
E. O. Hall andS. H. Algie,Metall Rev. 11 (1966) 61.
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Tawancy, H.M. Long-term ageing characteristics of Hastelloy alloy X. J Mater Sci 18, 2976–2986 (1983). https://doi.org/10.1007/BF00700780
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DOI: https://doi.org/10.1007/BF00700780