INSITU OBSERVATION OF UNIDIRECTIONAL SOLIDIFICATION IN TRANSPARENT ORGANIC ALLOY

In-situ observation of unidirectional solidification was carried out in the transparent organic compound salol which develops faceted cellular arrays. Growth rate and the profiles of temperature and solute concentration in the vicinity of the solid-liquid interface could be simultaneously measured in a microscopic interferometer. Displacement of interference fringes was observed at large growth rates. This implied that the distribution of temperature ahead of the interface was influenced by the released latent heat. It was found that faceted interface was kept isothermal during the solidification and that there was the reversed profile of temperature around the concave of the interface.