Hostname: page-component-cd9895bd7-q99xh Total loading time: 0 Render date: 2024-12-28T00:58:26.758Z Has data issue: false hasContentIssue false

Thermal and thermomechanical effects on defect evolution in an Al–Li superplastic alloy

Published online by Cambridge University Press:  26 July 2012

K. A. Padmanabhan
Affiliation:
Department of Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt, Germany
A. G. Balogh
Affiliation:
Department of Materials Science, Darmstadt University of Technology, Petersenstr. 23, 64287 Darmstadt, Germany
W. Puff
Affiliation:
Institute of Technical Physics, Technical University Graz, A-8010 Graz, Austria
Get access

Extract

A commercial Al–Li alloy, in which the superplastic microstructure is developed by “strain-assisted continuous recrystallization” in early stages of flow, was studied using positron annihilation lifetime spectroscopy. Results revealed that exposing the material to a temperature of 525 °C (optimal temperature of superplastic deformation for this alloy) led to agglomeration of single vacancies into vacancy clusters of size of approximately four vacancies. Evidence for superplastic strain-induced cavitation was not found at 450 °C up to an elongation of 432% and at 525 °C up to 341%, the initial strain rate of deformation in both cases being 1.0 ×10−3 s−1. These results have practical significance.

Type
Articles
Copyright
Copyright © Materials Research Society 1999

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.McKee, B. T. A., Carpentier, G. J. C., Walters, F. F., and Schults, R. J., Philos. Mag. A 41, 65 (1980).Google Scholar
2.Hidalgo, C., de Diego, N., and Plazaola, F., Phys. Rev. B 31, 6941 (1985).Google Scholar
3.de Diego, N. and Hidalgo, C., Philos. Mag. A 53, 123 (1986).Google Scholar
4.Romero, R., Silvetti, S. P., and Somoza, A., Scr. Metall. Mater. 24, 2225 (1990).Google Scholar
5.Dong, Y., Xiong, L.Y., and Lung, C. W., J. Phys.: Condes. Matt. 3, 3166 (1991).Google Scholar
6.Somoza, A., Romero, R., and Dupasquier, A., Mater. Sci. Forum 105–110, 1237 (1992).Google Scholar
7.Kim, J. and Bryne, J.G., Scr. Metall. Mater. 26, 1199 (1992).CrossRefGoogle Scholar
8.Ayciriex, M. D., Romero, R., Somoza, A., Silvetti, S. P., and Villagra, O., Scr. Metall. Mater. 28, 1577 (1993).Google Scholar
9.Dupasquier, A., Romero, R., and Somoza, A., Phys. Rev. B 48, 9235 (1993).Google Scholar
10.Padmanabhan, K. A. and Davies, G. J., Superplasticity, (SpringerVerlag, Berlin, 1980).Google Scholar
11.Kaibyshev, O. A., Superplasticity of Alloys, Intermetallide and Ceramics (Springer-Verlag, Berlin, 1992).Google Scholar
12.Gottstein, G., Brunger, E., Lochte, L., Fischer-Buhner, J., and Ponge, D., Proc. 16th Risø, Int. Symp. on Mater. Sci: Microstructural and Crystallographic Aspects of Recrystallization, edited by Hansen, M., Jensen, D. J., Liu, Y. U., and Ralph, B., Risø National Lab, Roskilde, Denmark (1995), p. 37.Google Scholar
13.Padmanabhan, K. A. and Lücke, K., Z. Metallkd. 77, 785 (1986).Google Scholar
14.Padmanabhan, K. A., Hirsch, J., and Lücke, K., J. Mater. Sci. 26, 5309 (1991).Google Scholar
15.Ricks, R. A. and Winkler, P. J., Proc. Sixth Int. Al–Li Conf., 1991 (Garmisch-Partenkirchen, Germany, edited by Peters, M. and Winkler, P. J. (Pub. DGM Informationsgesellschaft mbH, 1992), p. 1035.Google Scholar
16.Blackwell, P. L. and Bate, P. S., Superplasticity: 60 Years after Pearson, edited by Ridley, N. (The Institute of Materials, London, 1995), p. 183.Google Scholar
17.Hogg, B. G., Paulin, R., and Trojev, T. O., Phys. Status Solidi (a) K129, 54 (1979).Google Scholar
18.Mills, A. P., in Positron Solid-State Physics, edited by Brandt, W. and Dupasquier, A. (North-Holland, 1983), p. 4321.Google Scholar
19.Snead, C. L., Goland, A. N., and Wiffen, F. W., J. Nucl. Mater. 64, 195 (1977).Google Scholar
20.Padmanabhan, K. A., Engler, O., and Lücke, K., J. Mater. Sci. 31, 3971 (1996).Google Scholar
21.Bhattacharya, S. S., Ph.D. Thesis, IIT, Madras, India (1994).Google Scholar
22.Puff, W., Comput. Phys. Commun. 30, 359 (1983).Google Scholar
23.Hautojarvi, P., Positrons in Solids (Springer, Berlin, 1979).Google Scholar
24.Schaefer, H-E., Gugelmeier, R., Schmilz, M., and Seeger, A., Mater. Sci. Forum 15–18, 111 (1987).Google Scholar
25.Fluss, M. J., Smedskjaer, L. C., Chason, M. K., Legnini, D. G., and Siegel, R. W., Phys. Rev. B 17, 3444 (1978).Google Scholar
26.Seeger, A. and Banhart, F., Phys. Status Solidi A 102, 171 (1987).Google Scholar
27.Puska, M. J. and Nieminen, R. M., J. Phys. F 13, 333 (1983).Google Scholar