STRUCTURE OF DECAGONAL AL6PD

We present a detailed analysis of the peak shapes, positions, and intensities seen in electron diffraction and high-resolution powder X-ray diffraction patterns in the decagonal phase of rapidly quenched Al6Pd. We use two different models to analyse the data. In one case the material is considered to be a decagonal quasicrystal, in which the diffraction pattern results from five incommensurate vectors in a plane and one vector normal to that plane. In the other case the tenfold diffraction pattern is considered to arise from coherent twinning of microcrystals; additional multiple scattering is postulated to reconcile inconsistencies between the electron and X-ray diffraction patterns. Reasonable agreement is found with both models. © 1990 Taylor & Francis Group, LLC.