Distortion and Peak Broadening in Quasicrystal Diffraction Patterns

In this paper, we discuss how quenched strains in phonon and phason variables and/or quenched dislocations can lead to peak broadening and distortion in quasicrystal diffraction patterns. We argue that high-resolution electron micrographs and observations of distortions in electron diffraction patterns indicate the presence of anisotropic strains in the phason variable in the icosahedral phase of Al-Mn and related alloys. Such strains also contribute to the x-ray peak widths and line shapes.