Direct observation of thermoelectric magnetic convection in unidirectionally solidified Al-Cu alloys

摘要

This study performed the time-resolved and in-situ observation of unidirectional solidification of Al-Cu and Sn-Bi alloys under a static magnetic field up to 0.45T.In the case of Sn-Bi alloy,the static magnetic field reduced the local convection around the primary dendrite arms.No thermoelectric convection was detected.On the other hand,the thermoelectric convection was clearly observed in Al-Cu alloy.The observed convection was consistently explained by the thermoelectric magnetic convection.According to a simplified model,the thermoelectric magnetic convection can be induced if the difference in the thermoelectric power between the solid and the liquid phases is in the order of 1 μV/K and temperature gradient is several K/mm.