FLOW AND TEMPERATURE FIELD EVOLUTION DURING SOLIDIFICATION OF AN ELECTROMAGNETICALLY STIRRED MELT: INFLUENCE OF MAGNETIC SHIELDS

摘要

This paper investigates the effect of magnetic shield placement in proximity to an electromagnetically-stirred melt undergoing solidification. The electromagnetic field in both the molten metal and magnetic shields was computed using the mutual inductance technique. An improved dual-zone model was employed to describe the flow behavior in the mushy region. The key feature of the model is that it accounts for damping of the flow due to the interactions between the turbulent eddies and the crystallite surfaces. Calculations were performed for unidirectional solidification of an Al-based alloy in a bottom-chill mold for different shield geometries and locations. The magnetic shields were found to induce pronounced modifications to the flow characteristics of the melt, varying strongly with the shield placement. The evolution of both liquid fraction and temperature fields during solidification were likewise affected. The significance of these findings on grain refinement in electromagnetically-stirred melts will be discussed.