Abstract
Anomalous superlattice dark-field images of composite precipitates consisting of a dark core surrounded by a bright shell in Al-2.52Li-0.15Zr alloys, has been investigated by many beam dynamical image simulations employing a scattering matrix approach. The coherency strain field in the shell of the precipitate, as well as in the matrix, has been calculated by use of relations derived, and these are incorporated into the image calculations to determine whether the unexpected images can be elucidated by the coherency strain field of the precipitates. It has been found that the coherency strain field may modify the observed composite precipitate images, but it definitely cannot be the origin of the observed anomaly in these images. It has been also shown by the image matching technique, that the mismatch between the β' (Al3Zr) precipitates and aluminium matrix in Al-Li-Zr alloys should have a value of about 0.3%.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
P. L. Makin and B. Ralph, J. Mater. Sci. 19 (1984) 3835.
M. H. Tosten, J. M. Galbraith and P. R. Howell, J. Mater. Sci. Lett. 6 (1987) 51.
F. W. Gayle and J. B. Vandersande, Scripta Metall 18 (1984) 473.
Idem, Acta Metall. 37 (1989) 1046.
P. L. Makin, D. J. Lloyd and W. M. Stobbs, Philos. Mag. A51 (1985) L41.
P. J. Gregson and H. M. Flower, J. Mater Sci. Lett 3 (1984) 829.
T. Sato, Y. Kato, A. Kamio and T. Takahashi, Scripta Metall. 23 (1989) 447.
W. Stimson, M. H. Tosten, P. R. Howell and D. B. Williams, in “Proceedings of the 3rd International Confernce on Aluminium-Lithium Alloys”, Oxford, 1985, edited by C. Baker, P. J. Gregson, S. J. Harris and C. J. Peel (The Institute of Metals, London, 1986) p. 386.
P. B. Hirsch, A. Howie, R. B. Nicholson, D. W. Pashley and M. J. Whelan, “Electron Microscopy of Thin Crystals” (Butterworths, 1967) p. 276.
A. Howie and M. J. Whelan, Proc. R. Soc. Lond. A263 (1961) 217.
M. J. Goringe, in “Electron Microscopy in Material Science”, edited by U. Valdre (Academic Press, New York 1971) p. 463.
M. K. Aydinol, PhD thesis, Middle East Technical University, Ankara, Turkey (1994).
S. Timoshenko, “Theory of Elasticity” (McGraw-Hill, New York, 1934) p. 323.
E. Nes, Acta Metall 20 (1972) 499.
D. B. Williams and J. W. Edington, Metal Sci. 9 (1972) 529.
B. Noble, S. J. Harris and K. Dinsdale, J. Mater. Sci. 17 (1982) 461.
L. M. Brown and G. R. Woolhouse, Philos. Mag 21 (1970) 329.
O. Izumi and D. Oelschlagel, Z. Metallkde 60 (1969) 845.
M. F. Ashby and L. M. Brown, Philos. Mag. 8 (1963) 1083.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Aydinol, M.K., Bor, A.S. Coherency strain effects on TEM images of composite precipitates in Al-Li-Zr alloys. JOURNAL OF MATERIALS SCIENCE 31, 4883–4889 (1996). https://doi.org/10.1007/BF00355876
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/BF00355876