Microstructure evolution of immiscible alloy solidified under the effect of composite electric and magnetic fields

Solidification experiments were performed with Lead–Aluminum immiscible alloy under the effect of composite electric and magnetic fields (CEMFs). The results demonstrate that CEMFs not only decrease the size of minority phase particles (MPPs) but also promote a more uniform distribution of the MPPs. A theoretical model was built to describe the microstructure evolution during cooling the immiscible alloy. The solidification process of Pb–0.4 wt.%Al alloy under the effect of the CEMFs was simulated. The numerical results are well consistent with the experimental data. These results demonstrate that CEMFs affect the solidification process through changing melt convection and the nucleation behavior of minority phase droplets (MPDs). On one hand, the CEMFs can inhibit the convection and lead to the homogeneous distribution of MPPs along the radial direction of the sample. On the other hand, the CEMFs can increase the nucleation driving force for the MPDs, which decreases the average radius of MPDs and boosts the formation of dispersed solidification structures. This research indicates that the application of CEMFs is a promising strategy for controlling the microstructure of immiscible alloys.