Effect of phason strain on the transition of an octagonal quasicrystal to a<i>β</i>-Mn-type structure

Abstract

The process of transition from an octagonal quasicrystal to a crystal with \ensuremath{\beta}-Mn-type structure in Cr-Ni-Si alloy was investigated theoretically and experimentally. Using the linear phason strain field theory, the computer simulation of the diffraction patterns described the process of transition. The results of electron-diffraction experiments confirmed the correctness of the theoretical ones. The real-space tilings were also given. From the point of view of the geometric structural description, they also show the transition from octagonal quasiperiodicity to periodicity in a \ensuremath{\beta}-Mn-type structure. The transition involves the nucleation of regions of local translational periodicity in the original quasicrystal.