(上海大學(xué) 材料科學(xué)與工程學(xué)院， 上海 200072)
摘 要: 對不同成分Bi-Mn合金在液固兩相區(qū)和凝固過程中加磁場，考察磁場的磁感應(yīng)強(qiáng)度和加熱溫度對合金中MnBi相的影響。結(jié)果發(fā)現(xiàn)， MnBi相沿磁場方向定向排列并且聚合長大，形成規(guī)則的棒狀凝固組織。Bi-Mn合金中MnBi相在磁感應(yīng)強(qiáng)度為0.1T的磁場中就能夠明顯地沿磁場方向排列，MnBi相定向排列因子Γ隨磁感應(yīng)強(qiáng)度的增大和加熱溫度的升高而提高。在相同強(qiáng)度的磁場中，含Mn6%(質(zhì)量分?jǐn)?shù))的合金中， MnBi相定向排列所需的加熱溫度高于含Mn3%的合金。
關(guān)鍵字: 磁場；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
