The effect of the flow driven by a travelling magnetic field on solidification structure of Sn–Cd peritectic alloys

The effect of the flow driven by a travelling magnetic field (TMF) on solidification structure of Sn–1.8 wt% Cd peritectic alloy was investigated numerically and experimentally. A new TMF generator consisting of three co-coils and a cooling system has been designed and applied successfully. The corresponding radial and axial magnetic field intensity in the inner space of the TMF generator are measured by teslameter. Numerical results indicate that the flow velocity under a downward TMF is smaller than that under an upward TMF. The experimental results demonstrate that α island structures in β matrix are mainly observed under the 6.3 mT and 10.3 mT upward TMF, and the number of α island phase increases with increasing magnetic field intensity. Banded structure is observed under the 6.3 mT and 10.3 mT downward TMF, and the number of bands increases with increasing magnetic field intensity. This should be attributed to the different flow intensity at the interface front under an upward/downward TMF.

► A new travelling magnetic field (TMF) generator has been designed.
► The banded structure can form more easily under a downward TMF.
► An upward TMF appears not to be beneficial in the formation of banded structure.