Crystallochemical aspects of solid state reactions in mechanically alloyedAl-Cu-Fe quasicrystalline powders

A number of elemental mixtures having initial compositions close to Al65Cu2 3Fe12 were mechanically alloyed at different energy intensities using a pla netary mill. Laboratory X-ray diffraction analysis, differential scanning c alorimetry and Mossbauer spectroscopy were used for characterization of the phase and structural state of mechanically alloyed powders after different periods of milling and annealing. Several exothermic effects were found, a nd these were ascribed to specific solid-state reactions. Quantitative phas e analysis was applied in order to identify the mechanism of solid-state re actions laking place in the vicinity of the quasicrystalline phase domain i n the Al-Cu-Fe system as a result of mechanical and thermal excitation and homogenization, Metastable intermetallics were identified which possess cer tain structural and topological elements identical to those found in quasic rystals. (C) 2001 Acta Materialia Inc. Published by Elsevier Science Ltd. A ll rights reserved.