Hostname: page-component-77c89778f8-gvh9x Total loading time: 0 Render date: 2024-07-17T10:19:13.500Z Has data issue: false hasContentIssue false

Phase Evolution and Transformations During Long-Term Creep of Two-Phase Titanium Aluminides

Published online by Cambridge University Press:  15 February 2011

F. Appel
Affiliation:
Institute for Materials Research, GKSS Research Centre, Max-Planck-Straße, D-21502 Geesthacht, Germany, fritz.appel@gkss.de
M. Oehring
Affiliation:
Institute for Materials Research, GKSS Research Centre, Max-Planck-Straße, D-21502 Geesthacht, Germany, fritz.appel@gkss.de
P.J. Ennis
Affiliation:
Institute for Materials and Processes in Energy Systems, Research Centre Jülich, D-52425 Jülich, Germany
Get access

Abstract

Titanium aluminide alloys based on the intermetallic γ (TiAl) and α2 (Ti3Al) phases are being considered as light-weight materials for high-temperature applications in advanced energy conversion systems. However, for such applications the material suffers from insufficient creep resistance at the intended service temperature of 700°C. The paper reports an electron microscope study of diffusion controlled mechanisms which apparently cause the degradation of the strength properties. The processes lead to significant structural changes involving the formation of extended ledges and recrystallization. The driving forces of these mechanisms probably arise from non-equilibrium phase compositions and significant coherency stresses occurring at the interfaces.

Type
Research Article
Copyright
Copyright © Materials Research Society 2000

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

1. Beddoes, J., Wallace, W. and Zhao, L., International Materials Reviews 40, 197 (1995).Google Scholar
2. Parthasarathy, T.A., Mendiratta, M.G., and Dimiduk, D.M., Scripta Mater. 37, 315 (1997).Google Scholar
3. Oehring, M., Appel, F., Ennis, P.J., and Wagner, R., Intermetallics 7, 355 (1999).Google Scholar
4. Appel, F. and Christoph, U., Intermetallics 7, 1173 (1999).Google Scholar
5. van der Merwe, J. and Shiflet, G.J., Acta Metall. Mater. 42, 1173 (1994).Google Scholar
6. Cahn, R.W., Takeyama, M., Horton, J.A., and Liu, C.T., J. Mater. Res. 6, 57 (1991).Google Scholar
7. Hirth, J.P., Lothe, J., Theory of Dislocations, 2nd edn. (Krieger Publishing, Malabor, 1992).Google Scholar
8. Oehring, M., Klassen, T. and Bormann, R., J. Mater. Res. 8, 2819 (1993).Google Scholar