The objective of this paper is the experimental investigation of the microstructure in Al-6wt%Si-4wt%Cu alloy, directionally solidified without and with forced melt flow, induced by a rotating magnetic field. The flow leads to reduced primary dendrite spacing and to strong radial segregation of silicon and copper. As a consequence the local solidification conditions change, resulting in different types of Al2Cu phase formation. This outcome is explained by ThermoCalc calculations predicting the corresponding solidification behavior.
