Structural study of a superlattice Al-Ni-Ru decagonal quasicrystal using high-resolution electron microscopy and a high-angle annular dark-field technique

A high-quality superlattice Al-Ni-Ru decagonal quasicrystal with 0.4 nm per iodicity, formed in the conventionally solidified Al70Ni20Ru10 alloy, has b een studied by high-resolution electron microscopy and a high-angle annular dark-field (Z-contrast) technique. It has been clearly revealed that its s tructure is characterized as an a periodically ordered arrangement of decag on-shaped atomic columnar clusters which have a diameter of 2 nm and show p entagonal symmetry. On the basis of high-resolution electron microscopy str ucture images, and the atom-resolution Z-contrast observations which highli ght the transition-metal sites, the arrangement of atoms in the superlattic e decagonal quasicrystal are proposed.