中文摘要：

进行了纵向强磁场下MnBi/Bi过共晶定向凝固实验研究。发现磁场使得MnBi相的形态发生了明显变化,对于Bi-0.82wt%Mn过共晶MnBi/Bi定向凝固组织,在无磁场条件下,当生长速度V=5μm/s,温度梯度GL=50℃/cm时,MnBi按照小平面生长,形成中空六方形和＂V＂字形结构;施加磁场条件下,随着磁场强度的提高,MnBi相呈小平面生长的趋势逐渐增强。并且发现磁场的存在使得MnBi相明显粗化,相间距增大。从晶体生长学和磁学的角度分析了强磁场对过共晶MnBi/Bi定向凝固组织的影响。

英文摘要：

Effect of high vertical magnetic field on the directional solidification structure of hypereutectic Bi-Mn was investigated. It was found that high magnetic field enhanced MnBi phase grow in the facet growth form. At the same growth condition, the facet growth specialty of MnBi strengthened with the increasing of the applied magnetic field. For hypereutectic MnBi/Bi of Bi-0.82wt%Mn alloy, the cross section of MnBi was V-shaped and hexagon at certain growth condition （GL =50 ~C/cm and V=5 μm/s）. It was also found that interphase spacing and mean phase diameters increased with the increasing of the applied magnetic field. The solidified microstructure of Bi-Mn hypereutectic alloy under magnetic field was discussed on the base of magnetization and crystal growth theory.