Abstract
Unidirectionally solidified Al-4.5%Cu alloy ingots having columnar and feather crystals were homogenized for prolonged time up to 100hr. Completion of homogenization is delayed in the feather crystals. If the feather and columnar crystals are solidified under the same conditions, the former has the expanded secondary dendrite arm spacing, the increased mean Cu concentration, and the lower minimum Cu concentration in the α-matrix. The delay of homogenization in the feather crystals is partly attributed to these phenomena.
