The production of single-phase Al–Cu–Fe quasicrystals is a complex task requiring precise control of the synthesis parameters. High-energy ball grinding (HEBG) has proven to be an effective method for the synthesis of these materials due to the possibility of creating nanoscale structures and stimulating diffusion processes.
The experimental procedure involved mixing Al, Cu and Fe powders in a stoichiometric ratio corresponding to the composition Al62Cu25.5Fe12.5. The mixture was mechanically processed in a high-energy ball mill for various periods of time. After grinding, the powders were analyzed by X-ray diffraction (XRD) to identify the phase composition and determine the crystal structure.
The XRD results showed that after a certain grinding time, a single-phase Al–Cu–Fe quasicrystal was formed. Further increase in grinding time did not lead to significant changes in the phase composition. The resulting quasicrystals were characterized by a high degree of order and the absence of any other crystalline phases.
Aluminum-based quasicrystals, due to their unique combination of physical, thermal and mechanical properties, are of considerable interest for various applications, including the creation of hard coatings with a low coefficient of friction. However, since the stability of quasicrystalline phases is usually limited to narrow composition ranges, their industrial production faces certain difficulties.
Al67Cu23Fe10 alloys were synthesized using high-energy ball milling of elemental powders. The resulting powder samples consisted of a nanocrystalline Al(Cu, Fe) solid solution. Structural phase transformations in the ball-milled Al–Cu–Fe nanopowders were investigated by in situ X-ray diffraction at a constant heating rate at the B2 station of DESY-hasylab (Hamburg, Germany). High-quality single-phase quasicrystalline (QC) powders were obtained by slowly heating the nanocrystalline precursors to temperatures exceeding 750 °C. The resulting QC phase was retained during quenching and remained stable during subsequent heating to 800 °C.
Author: F. Turquier, V. D. Cojocaru, M. Stir, R. Nicula, E. Burkel
Institute: University of Rostock, Department of Physics, August-Bebel-Strasse 55, D-18055 Rostock, Germany