Real time study of the quasicrystal formation in annealed Al-Cu-Fe metallic multilayers

We present a study of the formation of the icosahedral Al-Cu-Fe quasicrystalline phase, when (Al, Cu, Fe) multilayers an heat treated. We first show that pure quasicrystalline films can be obtained in similar conditions, whatever the stacking sequence of the multilayers, even for quite thick elemental layers (hundreds or thousands of angstroms). Using synchrotron radiation diffraction, we, furthermore, study in real time the succession of intermediate phases forming during ramp heat treatments of the sandwiches. This study shows that in contrary to previous suggestions, the purl quasicrystalline phase can be prepared even when (Al, Cu) (and not (Al, Fe)) binary alloys form first. (C) 2000 Elsevier Science B.V. All rights reserved.