Demonstration of the g.b x u = 0 edge dislocation invisibility criterion for electron channelling contrast imaging

Dislocations with a large edge component do not exhibit a full loss of diffraction contrast in the transmission electron microscope unless the conditions g · b = 0 and g · b x u = 0 are simultaneously met. Because of a similarity between transmission electron microscopy (TEM) diffraction contrast and electron channelling contrast in the scanning electron microscope, the same contrast rules would be expected to apply for electron channelling contrast imaging (ECCI). Using the characteristic edge dislocations formed in annealed FeAl, it is demonstrated that the same extinction conditions apply for TEM diffraction contrast and ECCI.