INSITU OBSERVATION OF GROWTH MORPHOLOGIES IN SYSTEM WITH HIGH MELTING TEMPERATURES

Pattern formation during directional solidification from the melt is observed by optical methods. The investigations are made in the KCl-CsCl and the PbCl2-PbBr systems. The melting temperatures of the chosen compositions are approximately 750 and 430-degrees-C respectively. A detailed description of the experimental set-up is given. The results in the system of 95 mol% KCl + 5 mol% CsCl show that the relation between the primary dendrite spacing D and the growth velocity v is given by D alpha v-0.42; the relation between the tip radius and the growth velocity is R is-proportional-to v-0.53.