On the nature of phason planes in the complex metallic alloy ξ′-Al–Pd–Mn

A transmission electron microscopy study on phason planes, a type of defect involved in plasticity and phase transformations of the complex metallic alloy ξ′-Al–Pd–Mn, is presented. It is demonstrated that phason planes are not antiphase boundaries. The full displacement vector of a phason plane is determined by means of a fringe-contrast analysis. On the basis of the experimental results, an intuitive approach to the concept of metadislocations in terms of a Volterra-type construction process is presented.