Fast and reliable evaluation of lattice distortions from convergent-beam electron diffraction patterns

Abstract

A manual method for higher order Laue zone (HOLZ) line detection with an improved effective high-voltage correction for fast and reliable evaluation of local lattice distortions from convergent-beam electron diffraction (CBED) is presented. It is compared with a high-precision Hough transform method with a dynamic correction for each individual HOLZ line used by Krämer and Mayer. Both methods are applied to unfiltered and filtered experimental CBED patterns. As an example, the local lattice distortions in the γ − γ′ raft-like structure of a creep-deformed single-crystal nickel-based superalloy (CMSX-6) were measured. The lattice distortions obtained from both methods were analysed and showed good agreement. As a by-product, it was noted that specimen cooling enhanced the contrast of CBED patterns to the extent that the quality of CBED patterns taken at low temperatures without energy filtering was found to be qualitatively similar to that of CBED patterns taken at room temperature with energy filtering.