Temperature dependence of the 8-Å superstructure in decagonal Al–Co–Ni

Diffuse layers corresponding to an 8 A superperiod along the ‘periodic’ axis of decagonal Al–Ni–Co phases were investigated by in situ X-ray and neutron diffraction at temperatures up to 980 °C. The diffuse layers consist of an unstructured diffuse background, diffuse bands, and diffuse maxima which (almost) all vanish above 900 °C, but show a different temperature dependence in detail. A tentative scenario of the related structural ordering process during cooling from high temperature is developed. A 1D-columnar cluster model is compared to the experimental results.