Nonequilibrium effect of anisotropic interface kinetics on the directional growth of ice crystals

Directional growth experiments were carried out on ice crystals in a water-KCl solution system. It is well known that the effect of anisotropic interface kinetics causes tilting of the cell axes. The nonequilibrium effect of anisotropic interface kinetics, namely the kinetic supercooling Delta T-k, was estimated by observing the tilt angle of the cell axes, based on the theoretical prediction of linear stability analysis for small perturbations on a planar interface during directional growth. It was found that Delta T-k of an ice crystal during directional growth is minimum in the [<11(2)over bar 0>] direction, i.e., the dendrite tip growth direction, and maximum in the [<10(1)over bar 0>] direction. Therefore, it is shown that the preferred growth direction determined by anisotropic interface kinetics coincides with the direction by anisotropic interface free energy.