An Electromagnetic Compounding Technique for Counteracting the Thermoelectric Magnetic Effect During Directional Solidification Under a Transverse Static Magnetic Field

Abstract

An external direct current (DC) was introduced to counteract the thermoelectric magnetic effect during the directional solidification of Sn-10 wt pct Bi alloy under a 0.5 T transverse static magnetic field. The results show that the single-side Bi segregation induced by the thermoelectric magnetic effect gradually becomes weakened, disappeared, and then reversed with the increasing current density of the external DC. Therefore, a new method for counteracting the thermoelectric magnetic effect during materials processing under the magnetic field was proposed. In order to verify this method, the absolute thermoelectric power of Sn-10 wt pct Bi alloy and the internal thermoelectric current under the experimental conditions were measured and calculated, respectively. A 2D numerical simulation was established to simulate the evolution of the solid–liquid interface morphology, flow field, and composition segregation with the increasing current density of the external DC during directional solidification under a transverse static magnetic field. The present study not only facilitates the understanding of the effects of the forced flows on the directionally solidified microstructures and composition segregation, but also provides a new way for eliminating segregation and obtaining the higher-quality solidification structure by using the electromagnetic compounding technique.