王晖
,
任忠鸣
,
王秋良
,
严陆光
材料研究学报
研究了Bi--6\%Mn合金从低于446℃开始的半固态凝固过程中,
MnBi析出相磁致织构的形成过程和规律. 结果表明, 合金从355$\sim$446℃开始半固态凝固时,
合金中的MnBi相在340℃(MnBi相顺磁--铁磁转变温度)附近发生形态突变,
由规则的六方晶体转变为沿ab面长大的不规则片状晶体;
析出相的磁致织构是在发生磁性转变生成铁磁性MnBi相后通过晶粒旋转取向形成的.
合金从低于355℃开始半固态凝固, 导致织构形成的磁感应强度阈值随着温度的升高而降低,
从355$\sim$446℃之间开始的半固态凝固则相反.
磁场中合金从低于355℃开始的半固态凝固有利于制取高性能的过共晶Bi/MnBi磁性复合材料.
关键词:
金属材料
,
solidification
,
textured structure
,
magnetic field
,
Bi-Mn alloy
,
MnBi precipitated ph
Zhongming REN
,
Hui WANG
,
Kang DENG
,
Kuangdi XU
材料科学技术（英）
The solidification structure of Bi-3 wt pct Mn alloy grown up in the semisolid zone under the influence of a static magnetic field (up to 1.0 T) and the relation of the magnetic property with the solidification structure have been investigated experimentally. It was shown that the primary phase MnBi crystals in the alloy aligned and oriented along the direction of the applied magnetic field. The orientating tendency and the average length of the elongated MnBi crystals increased with the increase of the applied field and the solidification time. Moreover, the remanence of the alloy along the aligned direction of the MnBi phase in the case of solidification with a magnetic field was apparently anisotropic and nearly double of that without the magnetic field. This indicated that the MnBi crystals oriented and aligned along their easy magnetization axis. A model was proposed to explain the alignment and orientation growth of the MnBi crystals in a magnetic field in terms of the magnetic anisotropy of the crystals and the magnetic interaction between them.
关键词:
Magnetic field
,
null
,
null
,
null
