A critical examination of the dendrite growth models: Comparison of theory with experimental data

Abstract

Dendrite tip temperature, dendrite tip radius and primary arm spacing data, and their variation with the growth speed and temperature gradient for directionally solidified succinonitrile-acetone, succinonitrile-salol, aluminum-copper, and lead-paladium alloys have been examined against their qualititative and quantitative fit with predictions from several dendrite growth models. The Burden and Hunt analysis while predicting the proper quantitative behavior, does not in general, yield a good quantitative agreement with experimental data. Models due to Trivedi, and more recently, Laxmanan (minimum dendrite tip undercooling approach as well as the tip stability approach) show a very good quantitative fit with the experimental data. Predictions of dendrite tip temperature and tip composition in the liquid have been shown to be inadequate to distinguish between the models within the experimentally feasible directional solidification conditions. Therefore, in order to determine which model is most appropriate, additional directional solidification experiments involving simultaneous measurements of dendrite tip radius, tip temperature, tip composition, and primary arm spacing in the low growth velocity regime are suggested.