Directional solidification of undercooled melt

The directional solidification of highly undercooled single phase alloy is put forward. In contrast with the conventional directional solidification, it occurs under a negative temperature gradient at the solid/liquid interface. The essential condition for this process is that the thermal diffusion in liquid plays a dominant role in the crystal growth. An experiment on Cu-30at. %Ni alloy was conducted, and a directional solidification structure consisting of a single crystal was obtained in the undercooling range of 105-155 K.