Heterogeneous Nucleation of Eutectic Structure in Al-Mg-Si Alloys

The microstructure of Al-5Mg-2Si-0.4Mn-0.7Fe alloy solidified at different conditions were examined. Different kinds of eutectic structures such as (Al₁₅(Fe,Mn)₃Si₂ + α-Al), (Mg₂Si + α-Al) and (FIMCs + Mg₂Si + α-Al) were selected due to the different primary phases formation. The phase relationships between the phases within the eutectic structures, and the phase relationships between the primary phases and the eutectic leading phases were investigated. A well-defined orientation relationship (OR) between α-Al₁₅(FeMn)₃Si₂ and Mg₂Si was examined.