Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1678487 | Ultramicroscopy | 2006 | 11 Pages |
Abstract
The Vincent-Midgley precession technique has been used to collect three-dimensional electron diffraction intensity data from a dispersion of coherent precipitates in a matrix. In order to suppress severe effects from multiple diffraction via matrix reflections, a fairly large precession (tilt) angle had to be used. This implied a high background from the surrounding matrix, and limited the number of reflections that could be measured from patterns on image plates. The heavily faulted hexagonal ηâ²-precipitates (a=0.496nm, c=1.405nm) with thickness 3-5 nm occur in four equivalent orientations relative to the aluminium matrix; with frequent overlap of reflections. A model of the average structure in the space group P63/mmc with assumed composition Mg2Zn5âxAl2+x, have been derived by Patterson analysis and intensity comparisons.
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Authors
A. Kverneland, V. Hansen, R. Vincent, K. Gjønnes, J. Gjønnes,