| A study on the microstructure of rapidly solidified Al-Cr, Al-Zr, and Al-Ni alloys was carried out using levitation melting and two-piston apparatus. The microcrystalline structure of the rapidly solidified Al-Cr alloy transformed into a cellular structure showing a regularity as the solidification progressed. The effect of the initial temperature of liquid on the microstructure was not significant. A cluster of precipitate, confirmed to be Al_(11)Cr₂was thought to be formed in the undercooled liquid. The texture of the cellular structure was identified to be of $lt;111$gt; direction, which may be due to the anisotropy of interfacial energy and interface velocity in large undercooked liquid. In Al-Zr alloy, equiaxed α-Al grain structure of 1-5㎛ in size was obtained, in which intermediate compound A1₃Zr was supposed to act as a nucleation site of α-Al. In Al-Ni alloy of a hyper-eutectic composition (7 wt% Ni), the solidification development depended on the condition of contact with the substrate. In the case ofa bad contact the solidification development was microcell, cellular, dendrite, and equiaxed-grain which is nucleated by the A1₃Ni compound, while in the case of a good contact solidification transformed into a microcell, cellular, and rod-type eutectic structure. |
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