| The microstructure changes of rapidly solidified Al-Fe-Mo-Si alloys(Al-4Fe-0.5Mo-1.5-Si and Al-8Fe-2Mo-1.5Si) have been investigated by in -situ heating experiments at 450° and 500℃ in the transmission electron microscope. Both alloys contain two distinct regions : regions without solidification cell structure but with intergranular precipitates (A) and regions with intergranular precipitates (B) The fine nm-scale precipitates existing in Al-Fe-Mo-Si alloys coarsen during annealing. Intercellular precipitates in zone B of the Al-4Fe-0.5Mo-1.5Si alloy, which were initially of rod-like morphology, change into sphere-like particles after annealing for 10 minutes at 450℃. The precipitates in regions A and B are observed to obey an R³∝t kinetic relationship. On the other hand, the precipitates in Al-8Fe-2Mo-1.5Si alloy show no sign of coarsening at 450℃. At 500℃, however, the precipitates in the zone A of Al-8Fe-2Mo-1.5Si alloy coarsen slightly, but the precipitates in zone B do not coarsen appreciably. |
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