抄録
Dilute Al-Ti alloys containing Ti up to 0.13% and Al-Ti-B alloys containing Ti and B up to 0.05% and up to 0.05% respectively were unidirectionally solidified. A columnar crystal consists of a cellular dendrite, and an equiaxed crystal consists of a free dendrite. No foreign particles such as TiC, TiB2 and TiAl3 are observed in the center of each crystal. If the unidirectionally solidified ingot entirely having columnar crystals is remelted and cast fine equiaxed crystals appear. Fine crystals nucleated on the top of the mold wall have a granular shape because of solute segregation of Ti and B. Granular crystals easily separate from the mold wall and form free dendrite crystals.
