| Evolution of microstructure in a rapidly solidified Al-Fe-V-Si alloy has been investigated by TEM. The as-cast, microstructure varies depending on casting conditions and also through the thickness of melt-spun ribbon. Microstructure of the completely zone A ribbon consistis of the microcellular precipitation of the mocroquasicrystalline phase, with the globular particles of clustered mcroquasicrystalline phase near the air side of the ribbon. For the zone A and zone B mixed ribbon, on the other hand, intercellular particle is composed of silicide phase, but the formation of globular particles of microquasicrystalline phase(somewhat decomposed) is again observed near the air side of the ribbon. During heating, as observed by annealing studies and by in-situ hot-stage TEM studies, intercellular microquasicrystalline particles are quite nustable and decompose at a very fast rate, resulting in a coarse distribution of silicide particles. This decomposition of the intercellular microquasicrystalline particles assists the decomposition of glebular partioles of clustered microquasicrystalline phase in completely zone A ribbon, resulting in a very coarse distribution of silicide particles after annealing. For the zone A and zone B mixed ribbon, decomposition of globular particles of clustered microquasicrystalline phase results in the precipitation of silicide particles along the cell boundaries. |
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