Abstract
The microstructure characterisation of the quasicrystalline approximant Al₆₅Cr₂₈Fe₇ was performed by transmission electron microscopy, electron diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and other methods. In the investigated sample, two phases were identified: the metallic matrix possessing hexagonal structure with lattice parameters a = 1.2728 nm and c = 0.7942 nm (isostructural with the gamma-brass) and Al₂O₃ in the form of inclusions. The microstructure of the approximant was found to be formed by grains (their interior consists of plain and lamellate areas) surrounded by heterogeneous areas rich on the Al₂O₃ inclusions. The lamellate areas were found to be formed by parallel bands. Every other band showed the same orientation. In the band boundaries, the dislocation networks were found. It was shown that two sets of dislocations oriented nearly perpendicular to each other form dislocation networks also inside the bands.

Key words
quasicrystalline approximant, substructure, transmission electron microscopy

Full text (609 KB)