Simulation of electron microscope dislocation images in cubic and non-cubic structures

Abstract

For the quantitative evaluation of transmission electron microscope images of dissociated dislocations a contrast simulation program has been developed. These image simulations, based on methods described in the literature, use the column approximation and take into account many beams as well as linear anisotropic elasticity. The program also allows images to be simulated for samples containing any number of straight dislocations and planar faults and crystallized in the cubic, hexagonal, tetragonal, or orthorhombic structure. The defects can be positioned arbitrarily in wedge shaped samples. The shape of the samples allows the sign of the Burgers vectors to be obtained owing to the presence of thickness fringes. The image simulations show the influence of elastic anisotropy and of the positions of defects on their contrast.