(上海大学 材料科学与工程学院， 上海 200072)
摘 要: 对不同成分Bi-Mn合金在液固两相区和凝固过程中加磁场，考察磁场的磁感应强度和加热温度对合金中MnBi相的影响。结果发现， MnBi相沿磁场方向定向排列并且聚合长大，形成规则的棒状凝固组织。Bi-Mn合金中MnBi相在磁感应强度为0.1T的磁场中就能够明显地沿磁场方向排列，MnBi相定向排列因子Γ随磁感应强度的增大和加热温度的升高而提高。在相同强度的磁场中，含Mn6%(质量分数)的合金中， MnBi相定向排列所需的加热温度高于含Mn3%的合金。
关键字: 磁场；Bi-Mn合金；MnBi；凝固；定向排列
alignment structure of MnBi phase in
semi-solidified Bi-Mn alloy
（Department of Materials Science and Engineering,
Shanghai University, Shanghai 200072, China）
Abstract:The influences of magnetic flux density and heating temperature on alignment of the MnBi phase in mushy zone and during solidification of Bi-Mn alloy with a magnetic field were investigated experimentally. The results show that the MnBi crystals grow up and align along the field so that a regular club-shaped structure is formed. The alignment degree of MnBi increases with the in crease of magnetic flux density and heating temperature and 0.1T magnetic fie ld is enough to make the MnBi crystals aligned. The heating temperature needed to form aligned MnBi in 6%Mn(mass fraction) alloy is higher than that in 3%Mn alloy.
Key words: magnetic field; Bi-Mn alloy; MnBi; solidification; alignment
