Decomposition of quasicrystalline phase in a rapidly solidified Al-Fe-V-Si alloy

Decomposition of quasi-crystalline phase formed in a rapidly solidified Al-Fe-V-Si alloy has been studied by TEM. The as-cast microstructure varies through the thickness of melt-spun ribbon; microeutectic precipitation of the bcc silicide near the wheel side, formation of globular quasi-crystalline icosahedral phase with the microeutectic silicide phase at the middle of the ribbon, and the decomposition of quasi-crystalline phase near the air side of the ribbon. During heating, as observed by annealing studies and by in situ TEM studies, quasi-crystalline phase decomposes into various phases such as aluminum, silicide and other unidentified phases. It has been shown that the preferential sites for the transformation are either at the center of quasi-crystalline particles or at the quasi-crystal/matrix interface, depending on the location of quasi-crystalline particles. 13 refs