Formation of crystallographically aligned BiMn grains by semi-solid processing of rapidly solidified Bi-Mn alloys under a magnetic field
Formation of crystallographically aligned BiMn grains by semi-solid processing of rapidly solidified Bi-Mn alloys under a magnetic field
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DOI：
10.2320/matertrans.44.2207
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发表时间：
2003-10-01
影响因子：
1.2
通讯作者：
Kishio, K
中科院分区：
文献类型：
--
作者：
Yasuda, H;Ohnaka, I;Kishio, K
研究了Bi-Mn合金（20,30,40和50at%Mn）在磁场作用下凝固过程中晶粒的排列情况。在常规的包晶凝固过程中，由于晶粒旋转困难，通过包晶反应产生的BiMn晶粒没有排列。快速凝固在富bi基体中形成分布较细的BiMn晶粒，在非共晶成分中形成Bi-BiMn共晶组织。加热快速凝固的组织，即使对于Bi-50 at%Mn合金，也会产生半固态，其中不含平衡的BiMn相。悬浮在半固态的BiMn晶粒向有利方向旋转。旋转后的BiMn晶粒生长实现了BiMn晶粒的c轴排列。由快速凝固获得的初始组织控制的半固态对磁取向有重要作用。
Alignment of the BiMn grains during solidification under a magnetic field was examined for Bi-Mn alloys (20,30,40 and 50at%Mn). During the conventional peritectic solidification, the BiMn grains produced through the peritectic reaction did not align because of difficulties of the grain rotation. Rapid solidification produced the finely distributed BiMn grains in the Bi-rich matrix or the Bi-BiMn eutectic structure at off-eutectic compositions. Heating the rapidly solidified structure resulted in the semi-solid state even for Bi-50 at%Mn alloy, in which no semi-solid state containing BiMn phase in equilibrium. The BiMn grains suspended in the semi-solid state rotated in the favorable direction. Growth of the BiMn grains following the rotation achieved c-axes alignment of the BiMn grains. The semi-solid state, which is controlled by the initial microstructure obtained by the rapid solidification, is significantly useful for the magnetic alignment.