LIU Tie, JIANG Shan, ZHANG Baoze, MEI Shucheng, PAN Baifu, LI Zhe, LIU Yanxin, WANG Qiang
A high magnetic field, as an emerging non-contact high-energy physical field, can regulate metal solidification through multiple mechanical, magnetic and energetic effects, including Lorentz force, thermoelectromagnetic force, magnetization force, magnetic torque and magnetocrystalline anisotropy energy, without altering the chemical composition of materials, thus offering a new route for improving solidification structures and material properties. The research progress on solidification behavior and microstructure evolution of metals under high magnetic fields is systematically reviewed. The various magnetic field types and their basic modes of action are introduced, and their effects on fundamental physical properties such as electrical resistivity, wettability, diffusion coefficient, phase transformation temperature and magnetic susceptibility are summarized. From thermodynamic and kinetic perspectives, the regulatory mechanisms of magnetic fields on melt flow, momentum transfer, solute migration and solid/liquid interface stability are analyzed. The influences on composition segregation, solidification morphology, columnar-to-equiaxed transition, grain refinement, crystallographic orientation and second-phase particle morphology are further summarized. Existing studies indicate that various magnetic effects are coupled with temperature, flow, solute and interface evolution fields, and their dominant roles are jointly governed by magnetic field intensity, direction and gradient, temperature gradient, solidification rate and alloy magnetic susceptibility. Finally, it is proposed to establish quantitative criteria for the competition and synergy of multiple magnetic effects, to develop data-driven prediction and high-temperature in-situ characterization techniques under high magnetic fields, and to promote the engineering application of magnetic-field-assisted solidification.
