Effect of magnetic field intensity on the liquid state-dependent solidification of a Co-B hypereutectic alloy: Experiments and modeling

A systematic understanding of the effect of magnetic field intensity on the liquid state-dependent solidification of a Co-B hypereutectic alloy was carried out. The application of a magnetic field promotes nucleation, as evidenced by the reduction in undercooling, and the extent of the reduction is proportional to the intensity of the magnetic field. Nevertheless, for different liquid states, the magnetic field has dissimilar impacts on facilitating nucleation, manifested in the low-temperature liquid is more affected by the magnetic field, and the enhancing effect is more significant. A pre-nucleation model, modified from classical nucleation theory to include clusters as nucleation precursors, has been developed to describe the phenomena of liquid state-dependent nucleation. The model adeptly elucidates how the magnetic field intensity influences the nucleation of diverse melt structures differently, which is primarily attributed to the varying contact angles resulting from differences in surface tension as the magnetic field interacts with distinct melt structures. The present work might be helpful for not only theoretically understanding the effect of magnetic field intensity on the liquid state-dependent solidification but also providing an alternative strategy and criterion to tailor the microstructure and properties via magnetic field.