Direct observation of zonal dislocation in complex materials by atomic-resolution scanning transmission electron microscopy

Dislocation glide to carry plastic deformation in simple metals and alloys is a well-understood process, but the process in materials with complex crystal structures is not yet understood completely as it can be very complicated often involving multiple atomic planes during dislocation glide. The zonal dislocation is one of the examples predicted to operate in complex materials, and during glide it involves multiple atomic planes called shear zone, in which non-uniform atom shuffling occurs. We report direct observation made by Z-contrast atomic-resolution microscopy of the zonal dislocation in the sigma phase FeCr. The result confirms the zonal dislocation indeed operates in this material. Knowledge gained on the dislocation core structure will lead to improved understanding of deformation mechanisms in this and other complex crystal structures and provide ways to improve the brittleness of these complex materials. (c) 2022 The Authors. Published by Elsevier Ltd on behalf of Acta Materialia Inc.

Automated summary

Direct observation using Z-contrast atomic-resolution microscopy confirms the existence of zonal dislocation in the sigma phase FeCr. Understanding the dislocation core structure will improve the understanding of deformation mechanisms in complex crystal structures and provide methods to enhance the brittleness of these materials.