Dendritic growth kinetics and disorder trapping of the intermetallic compound Ni3Sn under a static magnetic field

Melts of the intermetallic compound Ni3Sn were undercooled using the glass fluxing technique with and without imposition of a static magnetic field of 1 T. Dendritic growth velocities in the undercooled melts were measured by in-situ monitoring of the recalescence process with a high-speed camera. The measured growth velocities show an abrupt increase at a critical undercooling of 190 K independent of the magnetic field. This observation presents evidence for complete disorder trapping in the Ni3Sn compound. The imposition of the magnetic field lowers the growth velocities for undercoolings below 190 K, but it does not alter the growth velocities for higher undercoolings. This impeding effect of the magnetic field can be explained within the framework of the current theory on dendritic growth by considering damped thermal transport in the undercooled melts.