Defectiveness of two-subgrain Al–Cu–Co single quasicrystals in vicinity of subgrain boundary

Two-subgrain single quasicrystals of a decagonal phase of the Al–Cu–Co alloy were studied by means of X-ray diffractometry and X-ray topography. The full width at half maximum (FWHM) of the 00002 X-ray reflection, in vicinity of the subgrain boundary, was determined. The measurements were carried out at different distances from the boundary. The relation of the FWHM versus the distance from the subgrain boundary was called the FWHM linear distribution. These distributions were determined for the “as grown” single quasicrystals, after their thermal treatment at 100 °C and after the subsequent treatment at 900 °C. From the distribution analysis it was concluded that the annealing at 100 °C causes certain defects to spread from the subgrain boundary towards the subgrain inner areas. The direction of the defect spreading tallied with the direction of the 10-fold symmetry axis. Change of the linear distributions after the treatment at 900 °C were discussed in the relation to the change of the domain structure and rotation of the subgrains in relation to one another.