Hostname: page-component-78c5997874-94fs2 Total loading time: 0 Render date: 2024-11-10T07:45:21.205Z Has data issue: false hasContentIssue false
  • English
  • Français

Quantitative analysis of microstructures produced by creep of Ti–48Al–2Cr–2Nb–1B: Thermal and athermal mechanisms

Published online by Cambridge University Press:  31 January 2011

M. A. Morris  and
M. Leboeuf
M. A. Morris
Affiliation:
Institute of Structural Metallurgy, University of Neuchêtel, Av. Bellevaux, 51, 2000 Neuchêtel, Switzerland
M. Leboeuf
Affiliation:
Institute of Structural Metallurgy, University of Neuchêtel, Av. Bellevaux, 51, 2000 Neuchêtel, Switzerland
Get access

Abstract

A γ-based TiAl alloy with equiaxed microstructure and fine grain size has been studied to analyze the deformation mechanisms responsible for the creep behavior. The microstructures produced by creep and high temperature deformation have been examined by TEM to obtain information about the different aspects characterizing the primary and secondary stages of creep. Mechanical twinning has been confirmed to occur in a fraction of the grains that never exceeds 50% while 1/2 ‹110› dislocations are active within all the γ grains. The twins are only responsible for a small amount of strain, but they lead to a subdivision of the microstructure and determine (directly or indirectly) the hardening process observed during the primary stage of creep. We have proposed that during the secondary stage the creep rate is determined by the unblocking of pinned dislocations by processes such as a pipe diffusion or cross slip that allow thermally activated glide of 1/2‹110› dislocations on (001) planes.

Type
Articles
Information
Journal of Materials Research , Volume 13 , Issue 3 , March 1998 , pp. 625 - 639
Copyright
Copyright © Materials Research Society 1998

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.Kim, Y. W. and Froes, F. H., High Temperature Aluminides and Intermetallics, edited by Whang, S. H., Liu, C. T., Pope, D. P., and Stiegler, J. U. (TMS, Warrendale, PA, 1990), p. 465.Google Scholar
2.Brady, M. P., Brindley, W. J., Smialek, J. L., and Locci, I., JOM 48, 46 (1996).Google Scholar
3.Takahashi, T., Nagai, H., and Oikawa, H., Mat. Trans. JIM 30, 1044 (1989).Google Scholar
4.Hayes, R. W. and London, B., Acta Metall. Mater. 40, 2167 (1992).Google Scholar
5.Es-Souni, M., Bartels, A., and Wagner, R., Acta Metall. Mater. 43, 153 (1995).Google Scholar
6.Beddoes, J., Wallace, W., and Zhao, L., Int. Mat. Rev. 40, 197 (1995).Google Scholar
7.Mitao, S., Tsuyama, S., and Minakawa, K., Mater. Sci. Eng. A 41, 51 (1991).Google Scholar
8.Bartholomeusz, M. F., Yang, Q., and Wert, J. A., Scripta Metall. 29, 389 (1993).Google Scholar
9.Hayes, R. W. and McQuay, P. A., Scripta Metall. Mater. 30, 259 (1994).Google Scholar
10.Worth, B. D., Jones, J. W., and Allison, J. E., Metall. Mater. Trans. A 26, 2947 (1995).Google Scholar
11.Wheeler, D. A., London, B., and Larsen, D. E., Jr., Scripta Metall. Mater. 26, 934 (1995).Google Scholar
12.Hayes, R. W. and Martin, P. L., Acta Metall. Mater. 40, 2761 (1995).CrossRefGoogle Scholar
13.Wang, J. N., Schwartz, A. J., Nieh, T. G., Liu, C. T., Sikka, V. K., and Clemens, D., in Gamma Titanium Alumindes, edited by Kim, Y-W., Wagner, R., and Yamaguchi, M. (TMS, Warrendale, PA, 1995), p. 949.Google Scholar
14.Beddoes, J., Zhao, L., Triantafillou, J., Au, P., and Wallace, W., in Gamma Titanium Aluminides, edited by Kim, Y-W., Wagner, R., and Yamaguchi, M. (TMS, Warrendale, PA, 1995), p. 959.Google Scholar
15.Oikawa, H., High Temperature Aluminides and Intermetallics, edited by Whang, S. H., Liu, C. T., Pope, D. P., and Stiegler, J. U. (TMS, Warrendale, PA, 1990), p. 353.Google Scholar
16.Jin, Z., Cheong, S-W., and Bieler, T., in Gamma Titanium Alumindes, edited by Kim, Y-W., Wagner, R., and Yamaguchi, M. (TMS, Warrendale, PA, 1995), p. 975.Google Scholar
17.Morris, M. A., Intermetallics 5, 339 (1997).Google Scholar
18.Morris, M. A., Philos. Mag. A 68, 237 (1993).CrossRefGoogle Scholar
19.Luster, J. and Morris, M. A., Metall. Mater. Trans. 26A, 1745 (1995).CrossRefGoogle Scholar
20.Jin, Z. and Bieler, T. R., Philos. Mag. A 71, 925 (1995).CrossRefGoogle Scholar
21.Groh, P., Dislocations et Déformation Plastique, edited by Groh, P., Kubin, L. P., and Martin, J. L. (Diffusion les Editions de Physique, Societé Française de Physique, 1979), p. 67.Google Scholar
22.Langdon, T. G., in Dislocation and Properties of Real Materials (The Institute of Metals, London, 1985), p. 221.Google Scholar
23.Poirier, J. P., Plasticité à Haute Temperature des Solides Cristallins (Editions Eyroles, Paris, 1976).Google Scholar