Grain refinement by electromagnetic stirring and the impact on the mechanical properties of alsi-alloys

This present study examines the directional solidification of AlSi7 alloys from a water cooled copper chill. A rotating magnetic field was used for melt agitation. Different magnetic field configurations were considered to demonstrate the impact of diverse flow conditions on the resulting microstructure and the mechanical properties. The solidified structure was evaluated in comparison to an unaffected solidified ingot. Measurements of the phase distribution, the grain size, the hardness and the tensile strength were performed. Our results reveal the potential of magnetic fields to control the grain size, the formation of segregation freckles and the mechanical properties. In particular, time–modulated rotating fields demonstrated their capability to homogenize both the grain size distribution and to improve the mechanical properties.