Phason Strains and Periodicity in Al-Ru-Cu Icosahedral Quasicrystals

Abstract
Phason strains in a stable AN-Ru-Cu quasicrystal prepared by a conventional melting method were examined by electron diffraction and high-resolution electron microscopy. The phason strains are frozen in an as-cast AN-Ru-Cu alloy, and then are relaxed and virtually disappear by annealing at a high temperature of 1118 K which is about 50 K below the melting point of the alloy. The frozen phason strains, which are homogeneous at a µm scale having a long-range correlation, show a tendency to produce a periodicity along one axial direction.