CONTROL OF INTERDENDRITIC CONVECTION BY THE APPLICATION OF TIME-DEPENDENT MAGNETIC FIELDS DURING DIRECTIONAL SOLIDIFICATION OF ALUMINIUM ALLOYS

摘要

Macrosegregations due to the application of electromagnetic fields during directional solidification of cylindrical Aluminium alloys are analyzed by the application of numerical modelling. We consider columnar solidification of AlSi7 alloys from the bottom to the top with a fixed growth velocity of v_G=0.1mm/s and a fixed temperature gradient of G=4K/mm ahead of the mushy zone. Controlled melt convection is achieved by the utilization of rotating and travelling magnetic fields. The presented numerical results are qualitatively confirmed by experimental measurements.