抄録
A simplified numerical model is presented to investigate the undercooling and solidification behavior of a hypereutectic Al–Si alloy during the mixing process of two kinds of molten alloys with different temperature and composition. This model involves a single slab of the second melt (Al–32 mass%Si alloy) stretching in the infinite bulk of the first melt (Al–12 mass%Si alloy). The second melt and, in some cases, a part of the first melt near the second melt are undercooled and solidified in the course of the mixing. The number of primary crystals is maximized at a certain strain rate of the stretching slab, depending on the initial thickness of the slab, while the maximum undercooling of the second melt increases as the strain rate increases. These results suggest that excessive agitation during the mixing may depress the refinement of the primary crystals.
