Lattice Boltzmann modeling of convective heat transfer and solute segregation during solidification of multi-component alloy in an electromagnetic field

In the solidification process of alloy with current, the Lorentz force generated by current and magnetic field will significantly affect the melt flow and solute segregation behavior in the melt pool. A multi-physics field lattice Boltzmann model is proposed to investigate the effects of Lorentz force on melt flow and solute segregation in solidification of multi-component alloy. The multi-relaxation time lattice Boltzmann (MRT-LB) equation is used to model the melt flow and coupled with the enthalpy equation, solute convective diffusion equation and static electromagnetic field equation. This study averaged the dendritic structure at the liquid-solid interface during solidification, without considering the actual dendritic morphology. Real-time access to the material parameters of the multi-component alloy is realized by coupling with the CALPHAD computed information. The accuracy of the present model is validated and verified by several benchmark cases. Finally, the influence mechanisms of different intensities of self-induced Lorentz force and stirring Lorentz force on the melt flow and solute segregation of Ti-6Al-4V alloy in a hemispherical molten pool were investigated by simulation. The results provide a detailed discussion on the effects of thermalsolutal buoyancy, self-induced Lorentz force, and stirring Lorentz force on melt flow and solute segregation. This study deepens the understanding of the effect of Lorentz force on melt flow and solute segregation, and proposes a model with wide practicality for the solidification process of metals in the presence of Lorentz force.