作为一种独特的金属基自生复合材料，难混溶合金组织、成分的均匀化和先析出相的弥散细化，是决定其优异性能的关键。由于磁场具有磁制动效应、磁力及热电磁效应，施加磁场对难混溶合金凝固过程可形成有效调控，因而成为电磁冶金的前沿领域之一。但迄今为止，有关磁场对难混溶合金凝固中第二相液滴析出、长大、迁移、凝并等动力学机制，仍远未深入。本项目提出磁场下X射线原位观察新思路，采用体凝固和Bridgeman凝固手段，从可视化的角度，研究多模式磁场（静磁场/交变磁场）下难混溶合金熔体中先析出相液滴的运动和长大行为，考察多模式磁场对先析出相的Stokes沉降、Marangoni迁移和液滴间的碰撞、凝并过程的影响机制，建立基于Hartman准数的先析出相液滴的迁移动力学模型，探讨实现难混溶合金凝固组织超细化的最佳磁场条件。本项目为实现多模式磁场均质化难混溶合金成分及组织，开发新的易偏析合金均质化制备技术提供理论借鉴

As a kind of special metal matrix in-situ composites, the homogenization of microstructure and dispersion of primary precipitated phase in immiscible alloy are the key conditions to determine its excellent properties. Due to the magnetic braking effect, magnetic force and thermal electromagnetic effect of magnetic field, the solidification process of immiscible alloy can be effectively modified by superimposing a magnetic field. Thus, the electromagnetic processing of materials is one of the frontier physical metallurgy. However, up to now, kinetics related to the precipitation of the second droplet phase in the solidification process of immiscible alloy under a magnetic field have been deeply studied. This project proposes a new idea about in-situ X-ray investigation method to study the movement and growth behavior of primary precipitated droplet under multi-mode magnetic fields (static magnetic field/alternating magnetic field) from a visualized angle. One of the aims is studying the mechanism about the effect magnetic field on the Stokes sedimentation, Marangoni migration of droplet and the collision, coalescence process between the droplets. Basing on the Hartman number, a migration kinetic model of primary precipitated droplet will be established. In addition, the other aim is discussing the optimized magnetic field parameters to realize the super refinement of the second phase in immiscible alloy. This project will offer a theoretical references for homogenization of microstructure and composition in immiscible alloy and, further, develop a new technology about manufacturing easy-segregation alloys with a homogenized microstructure.