Structural transformations in quasicrystal-forming quenched alloys of Al₆₁Cu₂₆Fe₁₃ subjected to isothermal annealing

Abstract

Conventional transmission electron microscopy (TEM) was employed to investigate structural transformations on annealing of rapidly solidified Al₆₁Cu₂₆Fe₁₃ alloys. In these alloys, β(CsCl)- and ι-phases reveal close to basic orientation relationships ( ‖ A5,  ‖ A2. The β-phase is characterized by short-range order with τ₃-type and ω-like displacements. On annealing at 450°C, a solid-state transformation of the β-phase (which has a copper concentration of 40–50 at.%) takes place by homogeneous precipitation of cuboid particles of a phase with triple the unit cell parameter 3a_β. This phase is regarded as close to β-based phases and the vacancy-ordered τ-phases. On annealing at 550°C, a single phase ι-structure is formed.

Acknowledgements

The authors thank Dr A.N. Yksysnikov for technical assistance and Mrs. N.G. Pomortseva for the help in preparing English version of manuscript. The TEM study was carried out in the Electron Microscopy Centre at the Ural Division of Russian Academy of Sciences. This work was supported by the 05-03-32186 RFBR grant.