Structure of One-Dimensional Al-Co-Ni Quasicrystal Studied by Atomic-Scale Transmission Electron Microscopy

Abstract

The structure of a one-dimensional Al–Co–Ni quasicrystal in an Al₇₁Co₁₉Ni₁₀ alloy annealed at 1100°C for 11 h has been studied by atomic-scale observations of high-angle annular detector scanning transmission electron microscopy and high-resolution transmission electron microscopy. Its structure can be characterized as a two-dimensional aperiodic arrangement of columnar clusters of atoms with a decagonal section of 2.0 nm in diameter and with pentagonal symmetry. In the arrangement of the atomic clusters, pairs of two lattice planes with high density of the atomic clusters are periodically arrayed with an interval of about 3 nm along the one direction. The atomic clusters with two orientations of pentagonal symmetry are randomly arranged with no special ordering manner.