Measurement Of Interfacial Energy Anisotropy And Study Of Free Dendritic Growth Of Succinonitrile

The Microscopic Solvability Condition (MSC theory) for pattern selection of dendritic growth is one of the most important theories of modern solidification researches. The definitive test of the above theories is a critical problem for the development of solidification theories, which can only be made through precise measurement of the anisotropic factor of the interface energy. In this paper, high purity SCN, which is widely used in solidification researches, was prepared high efficiently through a modified purification equipment, the anisotropic factor of the interface energy was further measured in SCN, and then free crystal growth dynamics behaviors were also investigated. The main conclusions are as follows:1. The high-purity SCN is obtained by vacuum fractional distillation and its purity is determined accurately through measuring the triple point. It is found that the purity of SCN can be better than 99.99% only after two distillation stages using our simple fractional distillation system. A new vacuum filling procedure is also developed to achieve the rapid and convenient filling of sample boxes with high-purity SCN under vacuum.2. Solid-liquid interfacial energy and its anisotropic factor of SCN are determined through measurement of grain boundary groove shape. The results shows that the average solid-liquid interfacial energy γ=6.79×10^-3J·m^-2, and the average anisotropic factor of the interfacial energy is 1.89% in SCN. It is also found that solid-liquid interfacial energy is linearly relevant with the temperature gradient, but the anisotropic factor of the interface energy is not. The shape characteristic of grain boundary groove and the orientation of the crystal grain have a remarkable effect on the measurement of anisotropic factor of the interfacial energy.3. The dendritic tip radius and growth velocity for different undercooling are measured. The marginal stability parameter is calculated. The reason of the difference between the experimental results and the current solidification theory and...