Analysis Of The Impact Of Macrosegregation On Hot Tearing Conditions During Dc Casting Of Aluminium Alloys

It is well known that the chemical composition has a strong impact on the hot tearing susceptibility of aluminium alloys. Macrosegregation formation during DC casting of aluminium may lead to large variations of the alloy composition. Assessments of the cracking susceptibility during DC-casting do not take into account composition variations within the ingot. A two-phase model where the main phenomena associated with the formation of hot tears are accounted for, i.e., the lack of feeding at the late stages of solidification and the localization of viscoplastic deformation, has recently been proposed by the authors. In the present study, the two-phase model is extended to allow for the computation of macrosegregation and its interaction with hot tearing formation. The impact of macrosegregation on mechanical fields often associated with the cracking tendency is assessed through case studies where both macrosegregation and the mechanical analysis are computed simultaneously. The case studies are carried out for the start-up of the DC casting process.