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Science 30 October 1987:
Vol. 238. no. 4827, pp. 660 - 663
DOI: 10.1126/science.238.4827.660
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Articles

Disorder in Al-Li-Cu and Al-Mn-Si Icosahedral Alloys

P. A. HEINEY 1, P. A. BANCEL 1, P. M. HORN 2, J. L. JORDAN 2, S. LAPLACA 2, J. ANGILELLO 2, and F. W. GAYLE 3

1 Department of Physics and Laboratory for Research on the Structure of Matter, University of Pennsylvania, Philadelphia, PA 19104.
2 IBM T. J. Watson Research Center, Yorktown Heights, NY 10598.
3 Metallurgy Laboratory, Reynolds Metals Company, P.O. Box 27003, Richmond, VA 23261.

Faceted dendrites of icosahedral AL6Li3Cu have been studied by high-resolution x-ray scattering. The samples display long-range icosahedral symmetry both in their diffraction patterns and in their macroscopic morphology. Despite the appearance of well-defined facets, the samples have a high degree of atomic disorder. The Bragg peaks have symmetry-dependent shapes and widths that scale linearly with Gperp (phason momentum). The peak widths are surprisingly similar to those found in icosahedral Al-Mn-Si alloys in both their absolute magnitude and their dependence on Gperp. The origin of these features in models for the icosahedral phase is discussed.

Submitted on May 21, 1987
Accepted on July 28, 1987


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Electron Localization in Metallic Quasicrystals.
F. S. Pierce, S. J. Poon, and Q. Guo (1993)
Science 261, 737-739
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