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Mechanical Properties and Dislocation Structures in TiAl Alloys with Varying Aluminum Contents

Published online by Cambridge University Press:  01 January 1992

S. Sriram
Affiliation:
Dept. of Materials Science and Engineering, University of Cincinnati, Cincinnati, OH, 45221
Vijay K. Vasudevan
Affiliation:
Dept. of Materials Science and Engineering, University of Cincinnati, Cincinnati, OH, 45221
Dennis M. Dimiduk
Affiliation:
Wright Laboratory, Materials Directorate, Wright-Patterson AFB, Dayton, OH, 45433.
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Abstract

Binary, coarse-grained polycrystalline Ti-48, 50 and 52 Al (in at.%) alloys, containing low (∼250 wt.ppm) levels of interstitials (O+N) have been deformed at various temperatures in compression and four-point bending. The 0.2% proof strength-temperature profiles are observed to comprise of three distinct regimes. Differences in the material response between bending and compression modes of deformation have been observed. Importantly, in both cases a flow stress anomaly is observed in the 50 and 52 Al alloys. Dislocation fine structures of samples deformed in compression, have been observed in the TEM. Analyses suggests the possible influence of Al contents on the line directions of dislocations, superdislocation dissociation modes, SISF dissociation distances and hence planar fault energies. Distinct differences in the deformation structures at RT and at the flow stress peak temperature (800°C) have been observed. These results are presented and discussed in relation with the observed mechanical properties.

Type
Research Article
Copyright
Copyright © Materials Research Society 1995

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References

REFERENCES

1. Shechtman, D., Blackburn, M. J. and Lipsitt, H. A., Metall. Trans., 5A, 1373 (1974).Google Scholar
2. Lipsitt, H. A., Shechtman, D. and Schafrik, R. E., Metall. Trans., 6A, 1991 (1975).Google Scholar
3. Hug, G., Loiseau, A. and Veyssiere, P., Phil. Mag., 54, 47 (1986).Google Scholar
4. Hug, G., Loiseau, A. and Veyssiere, P., Phil. Mag., 57, 499 (1988).Google Scholar
5. Kawabata, T., Kanai, T. and Izumi, O., Acta Metall., 33, 1355 (1985).Google Scholar
6. Vasudevan, V. K., Court, S. A., Kurath, P. and Fraser, H. L., Scripta Metall., 23, 467 (1989).Google Scholar
7. Prasad Rao, P. and Tangri, K., Mat .Sci. Engg., A132, 49 (1991).Google Scholar
8. Huang, S. C. and Hall, E. L., Scripta Met et Mat, 25,1805 (1991).Google Scholar
9. Pope, D. P. and Ezz, S. S., Int. Met. Rev., 29, 136 (1984).Google Scholar
10. Sriram, S., Vasudevan, V. K. and Dimiduk, D. M., Mat. Res. Soc. Symp., 213, 375 (1991).Google Scholar
11. Yang Chu, W. U. and Thompson, A. W., Scripta Met. 25, 641 (1991).Google Scholar
12. Hazzledine, P. M. and Sun, Y. Q., Mat. Res. Soc. Symp., 213, 209 (1991).Google Scholar
13. Court, S. A., Vasudevan, V. K. and Fraser, H. L., Phil. Mag., 6J, 141 (1990).Google Scholar
14. Woodward, C., MacLaren, J. M. and Rao, S., J.Mat. Res., 2 , 1735 (1992).Google Scholar
15. Hug, G. and Veyssiere, P., in: Proc. Int. Symp. of Electron Microscopy in Plasticity and Fracture Research of Materials (1989).Google Scholar