Atomic model of dislocations in Al-Pd-Mn icosahedral quasicrystals

Abstract

Using the Green's function and eigenstrain method, we derived an analytical expression for the elastic displacement fields induced by a dislocation in an icosahedral quasicrystal. In this paper, we calculate the special case where the line direction of the dislocation is parallel to a fivefold axis. Combining this expression with a structure model of icosahedral Al-Pd-Mn (the model of Boudard et al.) the atomic structure of straight dislocations was calculated and the corresponding high-resolution electron microscopy images were simulated. These are the first simulations of dislocations in an icosahedral quasicrystal using a realistic structure model. As an example, series of images of dislocations are presented with different twofold Burgers vectors of type |b⊥|/|b∥| = τ³ and |b⊥|/|b∥| = τ⁷ respectively, which were both observed experimentally. An analysis of the fringe patterns, obtained by inverse Fourier transformation of the simulated images is presented.