Abstract
The initiation mechanism of hot tearing in direct chill casting ingot of 7000 series aluminum alloy was investigated. In 7000 series aluminum alloys, the temperature range between solidus (463°C) and 583°C was classified into brittle range on mechanical properties and deformation behaviors in semi solid state. The brittle range of 7000 series aluminum alloys was larger than that of other general aluminum alloys. In 7000 series aluminum alloy, the healing of the crack which initiated from shrinkage cavity was difficult to occur especially in the center of the direct chill casting ingot which was the last solidification part. Therefore, it was considered that the hot tearing in direct chill casting ingot of 7000 series aluminum alloys was easy to initiate the crack in the center of the ingot.
