A study of the high-Cu Al–Cu–Co decagonal phase

Abstract

The decagonal phase was studied by transmission and scanning electron microscopy in an Al62Cu24Co14 alloy annealed at 550–850 °C. The electron diffraction patterns of the decagonal phase exhibited weak quasiperiodic odd-n reflections in the [1-2100] zone axis corresponding to the equilibrated structure. The relative intensities of these reflections were significantly lower in the Al62Cu24Co14 than in the Al68Cu11Co21 decagonal phase. Diffuse scattering observed previously at the same positions can be related to a nonequilibrium state of the decagonal phase.