Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-10T10:33:28.131Z Has data issue: false hasContentIssue false
  • English
  • Français

Compression and Compressive Creep Behaviors in Titanium Aluminides Alloyed with Vanadium comprizing Gamma + Beta Dual Phase Microstructures

Published online by Cambridge University Press:  26 February 2011

Tohru Takahashi ,
Yohji Kojima  and
Koshiro Otsuka
Tohru Takahashi
Affiliation:
takahas@cc.tuat.ac.jp, Tokyo University of Agriculture and Technology, Department of Mechanical Systems Engineering, Naka-cho 2-24-16, Koganei, Tokyo, 1848588, Japan, 81423887079, 81423887012
Yohji Kojima
Affiliation:
takahas@cc.tuat.ac.jp, Tokyo University of Agriculture and Technology, Department of Mechanical Systems Engineering, Na ka-cho 2-24-16, Koganei, Tokyo, 1848588, Japan
Koshiro Otsuka
Affiliation:
takahas@cc.tuat.ac.jp, Tokyo University of Agriculture and Technology, Department of Mechanical Systems Engineering, Naka-cho 2-24-16, Koganei, Tokyo, 1848588, Japan
Get access

Abstract

Fine grained gamma+beta dual phase microstructures were obtained in aluminum-titanium-vanadium ternary alloys containing 40 at.% aluminum and 60 at.% (titanium and vanadium). Average grain size was about 5, 3, and 2 micrometers in the recrystallized materials containing 20, 30, and 40 at.% vanadium, and the phase constitution was around 50vol.% gamma phase and 50vol.% beta phase. Compression behavior was investigated at temperatures ranging from the room temperature up to 1200K, and compressive creep tests were carried out at 1050-1200K in order to characterize the temperature and chemical composition dependences of strength and deformation. These gamma+beta microduplex materials showed very high strength at room temperature; 0.2% proof stress was around 1200MPa. The compression deformability decreased from about 0.2 to 0.05 true strain with increasing vanadium content. The grain size effect was not clarified yet, but it was rather disappointing that smaller-grained material with Al40Ti20V40 composition did not show effective improvement either in strength or in deformability. 0.2% proof stress showed a considerable weakening at temperatures higher than 900K; the onset temperature of softening became lower as the vanadium content increased. In Al40Ti40V20 material with about 5 micrometer grains, both gamma and beta grains were flattened up to 1000K, however, above 1100K the gamma grain showed no significant shape change even after a heavy deformation. This is probably because the gamma grains were relatively stronger than the beta grains. The gamma grains showed tendency toward agglomeration, which is similar to rafting of precipitate particles. Surface relief was observed after high temperature deformation suggesting activity of boundary sliding on grain boundaries and interfaces. Compressive creep behavior was investigated under a constant true stress in vacuum. Creep curves consisted of a small amount of normal primary transient, the minimum creep rate region, and a steady or slightly accelerating creep region. Stress exponent decreased to about 2 with decreasing vanadium content. It was rather unexpected that smaller grained Al40Ti20V40 material showed larger stress exponent around 3.

Keywords

alloyTiAl
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 980: Symposium II – Advanced Intermetallic-Based Alloys , 2006 , 0980-II05-02
Copyright
Copyright © Materials Research Society 2007

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. Lipsitt, H. A. in High-Temperature Ordered Intermetallic Alloys, edited by Koch, C. C., Liu, C. T., and Stoloff, N. S., (Mater. Res. Soc. Proc. 39, Pittsburgh, PA, 1985), 351.Google Scholar
2. Kim, Y.-W., J. of Metals 41, 24 (1989).Google Scholar
3. Yamaguchi, M. and Umakoshi, Y., Progress in Mat. Sci., 34 (Pergamon Press, 1991), 1.Google Scholar
4. Blackburn, M. J. and Smith, M. P., U.S. Patent No. 4 294 615, (13 Oct. 1981).Google Scholar
5. Mitao, S., Kohsaka, Y. and Ouchi, C., “THERMEC-88”, edited by Tamura, I. (Iron and Steel Institute of Japan, Tokyo, Japan, 1988), 620.Google Scholar
6. Maruyama, K., Takahashi, T., Oikawa, H., Mat. Eng. Sci. A153, 433 (1992).Google Scholar
7. Takahashi, T., Sakaino, Y., Song, S., Integrative and Interdisciplinary Aspects of Intermetallics, edited by Mills, M. J., Inui, H., Fu, C.-L. and Clemens, H., (Mater. Res. Soc. Proc. 842, Pittsburgh, PA, 2005), 169.Google Scholar
8. Takahashi, T., Asano, K., Hasegawa, K., Hasegawa, T., Mat. Sci. Eng. A239–240, 271 (1997).Google Scholar
9. Takahashi, T., Sujino, T., Abe, Y. and Hasegawa, T., in “Gamma Titanium Aluminides 1999”, (The Minerals, Metals & Materials Society, 1999) pp.733–740.Google Scholar
10. Villars, P., Prince, A. and Okamoto, H. (editors), “Handbook of Ternary Alloy Phase Diagrams”, (ASM, Materials Park, PA, 1995 ), 4, 4367.Google Scholar
11. Petzow, G. and Effenberg, G. (editors) , “Ternary Alloys - A Comprehensive Compendium of Evaluated Constitutional Data and Phase Diagrams” (VCH, 1993), 8, 426.Google Scholar
12. Hashimoto, K., Doi, H. and Tsujimoto, T., J. Japan Inst. of Metals, 49, 410 (1985).Google Scholar
13. Takahashi, T., Asano, K., Ashida, D., Murakoshi, T. and Hasegawa, T., “Thermec 2000, Processing and Manufacturing of Advanced Materials”, CDROM Section E3, Vol.117/3 “Special Issue: Journal of Materials Processing Technology, Elsevier Science, UK”, (2001).Google Scholar
14. Takahashi, T., Otsuka, K., Murakoshi, T. and Hasegawa, T., Proc. 3rd Int. Symp. on Gamma Titanium Aluminides, (TMS, 2003), 113.Google Scholar