A new application of the large-angle convergent-beam electron diffraction t
echnique for the determination of the displacement vector R at a Sigma 3 gr
ain boundary in Cu + 6 at% Si alloy is presented here. It is shown that in
large-angle convergent-beam diffraction many high-index reciprocal coincide
nt site reflections, g(c), can be utilized to obtain the phase factor of g(
c).R, allowing a high accuracy for the determination of R. In this study th
e value of R at an asymmetric boundary of (1 2 1)/(5 2 5) in a ((1) over ba
r 2 (1) over bar) twin is accurately determined. This result indicates that
there is no excess volume at this boundary. (C) 1999 Published by Elsevier
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