Skip to main content Accessibility help
×
Home

Creep and Fracture Mechanisms in an Oxide-Dispersion Strengthened Ni3Al-Based Alloy Between 649°C and 982°C

  • Ralph P. Mason (a1) and Nicholas J. Grant (a2)

Abstract

An oxide-dispersion strengthened (ODS) Ni3Al-based alloy has been fabricated and creep tested. Previously reported data for minimum creep rate as a function of stress indicated that two creep mechanisms operate at intermediate temperatures of 732 and 816°C [1]. This paper reports the results of recent interrupted creep tests and fractographic studies which serve to identify the two creep mechanisms. Creep at low stresses or low creep-rates occurs by constrained growth of cavities on transverse grain boundaries. In this low stress region an apparent stress exponent of 5.1 is observed. Creep at high stresses or high creep-rates results from the bulk deformation of grains by power law creep with a much smaller contribution due to grain boundary cavitation. The stress exponents of 13 and 22 observed in this high stress region are typical of ODS alloys. In both regions fracture is observed to be mixed mode with a large transgranular component due to the high grain aspect ratio developed in this material. Limited data at 982°C indicate the occurrence of only one mechanism which can be described by a stress exponent of 9.1. It was not possible, based on fractographic studies, to associate the creep mechanism at 982°C with either of those observed at the intermediate temperatures. No fractographic studies were performed at 649°C due to lack of valid specimens; however, the stress exponent of 13.5 observed at 649°C suggests that creep occurs by deformation of the grains.

Copyright

References

Hide All
1 Mason, R.P. and Grant, N.J., in Proc. of 3rd International Conference on High-Temperature Intermetallics, 1619 May 1994, San Diego, CA., to be published in Mater. Sci. and Engrg. A.
2 Nathal, M.V., Diaz, J.O. and Miner, R.V. in High-Temperature Ordered Intermetallic Alloys III, edited by Liu, C.T., Taub, A.I., Stoloff, N.S., and Koch, C.C. (Mater. Res. Soc. Proc. 133, Pittsburgh, PA, 1989) pp. 269274.
3 Shah, D.M. and Duhl, D.N., in High-Temperature Ordered Intermetallic Alloys II. edited by Stoloff, N.S., Koch, C.C., Liu, C.T., and Izumi, O. (Mater. Res. Soc. Proc. 81, Pittsburgh, PA, 1987) pp. 411417.
4 Mason, R.P., PhD. Thesis, Massachusetts Institute of Technology, Dept. of Materials Science and Engrg., Cambridge, MA, 1993.
5 Zeizinger, H. and Arzt, E., Z. Metallkunde 79,774 (1988).
6 Stephens, J.J. and Nix, W.D., Metall. Trans. A 17A, 281 (1986).
7 Stephens, J.J. and Nix, W.D., in Superallovs 84. edited by Gell, M., (TMS-AIME, Warrendale, PA, 1984) pp. 327–.
8 Stephens, J.J. and Nix, W.D., Metall. Trans. A 16A, 1307 (1985).
9 Wiegert, W.H. and Henricks, R.J., in Superallovs 1980. edited by Tien, J.K., Wlodek, S.T., Morrow, H., Gell, M., and Maurer, G.E. (ASM, Metals Park, OH, 1980) pp. 575584.
10 Grant, N.J. and Chaudhuri, A.R., in Creep and Rupture. (American Society for Metals, Cleveland, 1957), p. 284.

Creep and Fracture Mechanisms in an Oxide-Dispersion Strengthened Ni3Al-Based Alloy Between 649°C and 982°C

  • Ralph P. Mason (a1) and Nicholas J. Grant (a2)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed