Hostname: page-component-cd9895bd7-mkpzs Total loading time: 0 Render date: 2024-12-27T01:50:13.978Z Has data issue: false hasContentIssue false
  • English
  • Français

Influence of Quenching Rates on the Transformation of Ternary Phases in Nb-rich γ-TiAl Alloys

Published online by Cambridge University Press:  20 January 2011

Andreas Stark ,
Michael Oehring  and
Florian Pyczak
Andreas Stark
Affiliation:
Institute of Materials Research, Helmholtz-Zentrum, Geesthacht Centre for Materials and Coastal Research, Max-Planck-Str. 1, D-21502 Geesthacht, Germany
Michael Oehring
Affiliation:
Institute of Materials Research, Helmholtz-Zentrum, Geesthacht Centre for Materials and Coastal Research, Max-Planck-Str. 1, D-21502 Geesthacht, Germany
Florian Pyczak
Affiliation:
Institute of Materials Research, Helmholtz-Zentrum, Geesthacht Centre for Materials and Coastal Research, Max-Planck-Str. 1, D-21502 Geesthacht, Germany
Get access

Abstract

Intermetallic γ-TiAl based alloys with additional amounts of the ternary bcc β phase attracted increasing attention in recent years due to their improved workability at elevated temperatures. At lower temperatures the ductile high-temperature β phase can transform to several ordered phases. However, actually available phase diagrams of these multiphase alloys are quite uncertain and the precipitation kinetics of some metastable phases is far from understood.

In the present study various transformations of the third phase are observed in situ by means of high-energy x-ray diffraction using synchrotron radiation. A Ti-45Al-10Nb (at.%) specimen is subject to a temperature ramp of repeated heating cycles (700 °C - 1100 °C) with subsequent quenching at different rates. Depending on the quenching rate reversible transformations of the B2-ordered βo phase to different ω related phases are observed in Ti-45Al-10Nb. At low quenching rates the hexagonal B82-ordered ωo phase is formed while at high quenching rates the metastable intermediate trigonal ω’’ phase can be preserved. The results indicate that the complete transformation from βo to hexagonal B82-ordered ωo consists of two steps which are both diffusion controlled.

Keywords

phase transformationx-ray diffraction (XRD)crystallographic structure
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1295: Symposium N – Intermetallic-Based Alloys for Structural and Functional Applications , 2011 , mrsf10-1295-n03-07
Copyright
Copyright © Materials Research Society 2011

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

REFERENCES

1. Appel, F. and Oehring, M., in Titanium and Titanium Alloys, edited by Leyens, C. and Peters, M. (Wiley-VCH, Weinheim, Germany, 2003) p. 89.Google Scholar
2. Kestler, H. and Clemens, H., in Titanium and Titanium Alloys, edited by Leyens, C. and Peters, M. (Wiley-VCH, Weinheim, Germany, 2003) p. 351.Google Scholar
3. Structural Aluminides for Elevated Temperature Applications, edited by Kim, Y.-W., Morris, D., Yang, R. and Leyens, C. (TMS, Warrendale, PA, USA, 2008).Google Scholar
4. Takeyama, M. and Kobayashi, S., Intermetallics 13, 993 (2005).Google Scholar
5. Appel, F., Oehring, M. and Paul, J. D. H., Adv. Eng. Mater. 8, 371 (2006).Google Scholar
6. Clemens, H., Wallgram, W., Kremmer, S., Güther, V., Otto, A. and Bartels, A., Adv. Eng. Mater. 10, 707 (2008).Google Scholar
7. Liss, K.-D., Schmoelzer, T., Yan, K., Reid, M., Peel, M., Dippenaar, R. and Clemens, H., J. Appl. Phys. 106, 113526 (2009).Google Scholar
8. Witusiewicz, V.T., Bondar, A.A., Hecht, U. and Velikanova, T.Ya., J. Alloys Comp. 472, 133 (2009).Google Scholar
9. Schmoelzer, T., Liss, K.-D., Zickler, G. A., Watson, I. J., Droessler, L. M., Wallgram, W., Buslaps, T., Studer, A. and Clemens, H., Intermetallics 18, 1544 (2010).Google Scholar
10. Stark, A., Bartels, A., Clemens, H. and Schimansky, F.-P., Adv. Eng. Mater. 10, 929 (2008).Google Scholar
11. Bystrzanowski, S., Bartels, A., Stark, A., Gerling, R., Schimansky, F.-P. and Clemens, H., Intermetallics 18, 1046 (2010).Google Scholar
12. Gogia, A. K., Nandy, T. K., Banerjee, D., Carisey, T., Strudel, J. L. and Franchet, J. M., Intermetallics 6, 741 (1998).Google Scholar
13. Liss, K.-D., Bartels, A., Schreyer, A. and Clemens, H., Textures Microstruct. 35, 219 (2003).Google Scholar
14. Staron, P., Fischer, T., Lippmann, T., Stark, A., Daneshpour, S., Schnubel, D., Uhlmann, E., Gerstenberger, R., Camin, B., Reimers, W., Eidenberger, E., Clemens, H., Huber, N. and Schreyer, A., Adv. Eng. Mater. 13, in press (2011).Google Scholar
15. Stark, A., Textur- und Gefügeentwicklung bei der thermomechanischen Umformung Nb-reicher Gamma-TiAl-Basislegierungen (Shaker Verlag, Germany, 2010).Google Scholar
16. Bendersky, L., Boettinger, W., Burton, B., Biancaniello, F. and Shoemaker, C., Acta Metall. Mater. 38, 931 (1990).Google Scholar
17. Sanati, M., West, D. and Albers, R. C., J. Phys.: Condens. Matter 20, 465206 (2008).Google Scholar