Effects of Si content and pulsed magnetic field on the AlSi alloys: An experimental and multiphysics simulation study

This study explored the influence of silicon (Si) concentration and pulsed magnetic field (PMF) on the morphology of AlSi alloys through experiments and multiphysics simulations. The research illustrates that the as-cast commercial purity aluminum (CP-Al) exhibits coarse columnar crystals, whereas the addition of Si changes the macrostructure into equiaxed grains. Upon the addition of Si, the average grain size of AlSi alloys initially decreases, but then begins to increase. Notably, Al2Si exhibits the finest grain size. This indicates that solute content plays a dominant role in the morphology of AlSi binary alloy, mainly due to the solidification interval. Furthermore, the application of PMF leads to significant refinement of grain size in AlSi alloys. Specifically, with increasing Si content, the grain initially increases, then undergoes a decrease before subsequent increase. The finest grain size is observed in CP-Al, followed by Al2Si. Additionally, the forced convection of AlSi alloys induced by Lorentz force is basically the same, but the temperature gradients and instantaneous cooling rates are significantly altered. Phase field simulations indicated that fluid flow promotes more pronounced dendrite growth in the flow direction, along with solute migration and localized solute enrichment.