Abstract:The diversity of interface morphologies is observed for directionally solidified Sn-0.65%Cd alloy under a travelling magnetic field (TMF) in the 4 mm-diameter sample. Under an upward TMF, planar and cellular interface morphologies transform alternately with increasing magnetic flux density (B≤10.3 mT). The interface morphology transforms from shallow cellular to deep cellular morphology under a weak downward TMF (B=3.2 mT). When the magnetic flux density increases further, both sides of the interface morphology appear to be slightly inconsistent, but they roughly tend to be planar under a strong downward TMF (B≤10.3 mT). The interface instability may be attributed to the flow driven by the TMF. Moreover, the shape of interface appears to be almost flat under an upward TMF, but deflective under a downward TMF.

Key words: directional solidification; travelling magnetic field; interface morphology; Sn-Cd alloy