3D phase field-lattice Boltzmann modeling of microstructure evolution in binary alloys
The aim of this project is the development of a phase-field based lattice Boltzmann method to investigate the solidification of binary alloys taking into account the effects of diffusion, convection and buoyancy.
Microstructure evolution under the combined effects of diffusion, forced advection and buoyancy driven flow provides a research field with a very rich phenomenology already for a material composed of one single element. The situation is still more interesting when binary alloys are considered. In this case, when combined with solidification, the competition between thermodynamic driving forces on the one hand and flow-induced kinetics on the other hand may give rise to a complex microstructure. Fluid flows during the solidification process are inevitable in metallurgy (e.g. strand casting). Hence, it is of great industrial interest to understand the effect of individual parameters such as the relative strength of buoyancy flow as compared to diffusion as well as the subtle effects related to the flow patterns on the resulting microstructure. An important aim of such a study is to provide specific hints on how to tune the control parameters in order to obtain a desired microstructure. The present project aims at addressing this problem for the specific case of binary alloy solidification. The use of a combined phase field-lattice Boltzmann approach naturally arises from the fact that these two methods have proved to be reliable, efficient and complementary with regard to two basic involved processes. While phase field is best suited for a study of microstructure evolution, the lattice Boltzmann method is the method of choice when it comes to flow in intricate geometries as is usually the case during microstructure evolution. The ultimate goal of this project is to develop methodological and computational tools allowing tackling comprehensively complex phenomena such as sedimentation of dendrites during solidification and its influence on microstructure evolution.