Tailoring homogeneous immiscible alloy via magneto-Archimedes levitation

Processing of immiscible alloys with a homogeneous distribution of fine minor segregated phases is a great challenge. Al-10wt.%Bi immiscible alloys were solidified under the homogeneous and gradient high magnetic fields (HHMF and GHMF). X-ray computed tomography technique was applied to study the spatial features of the minor Bi-rich particles (MBPs). The results show that the MBPs displayed as centripetal and centrifugal distributions along the radial directions of the ingots solidified under the GHMF. The segregation of the minor Bi-rich droplets (MBDs) was dominated by both radial Marangoni migration and the vertical Stokes sedimentation under the HHMF. In the case of the GHMF, both the radial Marangoni migration and vertical Stokes sedimentation of the MBDs can be effectively stopped by the gradient forces. This work provides a novel path to design the novel alloys with homogeneous microstructures by utilizing the magneto-Archimedes levitation.