Uses of electron channelling in studying material deformation

Abstract

Channelling contrast arises from variations in the intensity of electron diffraction from the various planes within a crystal as the beam angle is changed within a scanning electron microscope. Channelling-contrast micrographs may be made in any scanning electron-beam instrument, and selected-area electron -channelling patterns may be produced in many of these instruments. The patterns observed are uniquely dependent upon the relative orientation of the electron beam direction and the planes of the crystal, and the acuity of the lines depends directly on the density of defects and their arrangement in the crystal. Channelling-contrast micrographs may be used to observe the tilting of portions of the grains that occurs during the formation of subcells. This review examines the origin of channelling contrast and the ways in which it may be used in the study of material deformation. Specific applications are referred to and illustrated.