LACBED study of a Σ3 grain boundary in a Cu +6 at% Si alloy

A new application of the large-angle convergent-beam electron diffraction technique for the determination of the displacement vector R at a Σ3 grain boundary in Cu+6 at% Si alloy is presented here. It is shown that in large-angle convergent-beam diffraction many high-index reciprocal coincident site reflections, gc, can be utilized to obtain the phase factor of gc·R, allowing a high accuracy for the determination of R. In this study the value of R at an asymmetric boundary of (1 2 1)/(5 2 5) in a (1̄ 2 1̄) twin is accurately determined. This result indicates that there is no excess volume at this boundary.