COOLING AND CRYSTALLIZATION OF MOLTEN ALUMINUM ALLOY DROPS IN WATER

The physical processes of crystallization of melt drops in water were studied using the drop granulation and melt centrifugation methods. A mathematical model was developed to determine the cooling and crystallization rates and structural dendritic parameter for aluminum alloy granules based on the initial data of the process, the diameter of melt drops, and cooling conditions. Predicting the dendritic parameter of the microstructure of granules makes it possible to predict the level of microstructure dispersion and hence the strength properties of the granulate material. The model parameters take into account the drop speed, features of heat removal processes, and the temperature dependence of the thermophysical parameters of the media. An application program implementing the developed mathematical model was developed. The developed mathematical model was implemented using the Microsoft Visual C++ programming language. The mathematical model was tested for the granulation of high-alloyed aluminum alloys (D1 and D16 alloys of the Al–Cu–Mg system, and B95 and B96Ts alloys of the Al–Zn–Mg–Cu system) obtained by centrifugal melt spraying and the drop method with cooling in water. Crystallization rate in full-scale samples was measured based on an analysis of the structural dendritic parameter of the material. Analysis of the calculated values of the dendritic parameter and its measurements for real granule samples shows good convergence of the simulation and measurement results.