Crystal Growth in Undercooled Ni-18.7at.Sn Eutectic Melt

摘要

Ni-18.7at.%Sn melt was undercooled and solidified in the encasement of glass flux. Temperature recalescence in the surface layer of sample was partially depressed due to its contact with the glass, which remained more of the rapidly solidified structure to the room temperature. It was clearly revealed that the alloy melt solidified into eutectic dendrite at low undercooling. At the undercooling higher than 130 K, however, α-Ni dendrites formed first. Taking the thermal diffusion into account, a model to describe the eutectic growth in undercooled melts was established, and an excellent agreement between theoretical prediction and experimental result was achieved.