Study on the Effect of Melt Convection on Phase Separation Structures in Undercooled CuCo Alloys Using an Electromagnetic Levitator Superimposed with a Static Magnetic Field
Study on the Effect of Melt Convection on Phase Separation Structures in Undercooled CuCo Alloys Using an Electromagnetic Levitator Superimposed with a Static Magnetic Field
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DOI：
10.1007/s11663-014-0052-9
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发表时间：
2014-08-01
影响因子：
3
通讯作者：
Fukuyama, Hiroyuki
中科院分区：
文献类型：
--
作者：
Sugioka, Ken-ichi;Inoue, Takamitsu;Fukuyama, Hiroyuki
利用电磁悬浮装置研究了熔体对流对Cu80Co20过冷合金相分离结构的影响，并利用静磁场控制了熔体中的对流。结果表明，在较小的静磁场作用下，富Co相的组织弥散分布在富铜相的基质中。然而，当磁场超过某一值，即本研究中约1.5T时，富铜基质中出现了几个大的聚集态富钴相。富铜相基质中分布的液滴状富钴相的平均直径随着磁场的增加而逐渐增大，在1.5T附近迅速增大。根据周期性激光加热的结果推测，在1.5T附近相分离结构的显著变化可能是由于熔体中从湍流到层流的对流转变，其中测量了当样品上部被周期性加热时，电磁悬浮熔体下部温度的时间变化。
We studied the effect of melt convection on phase separation structures in undercooled Cu80Co20 alloys by using an electromagnetic levitator, where a static magnetic field was applied to control convection in the molten alloys. It was found that, when the static magnetic field was relatively small, dispersed structures with relatively fine Co-rich spheres distributed in the matrix of the Cu-rich phase were observed. However, a few large, coalesced Co-rich phases appeared in the Cu-rich matrix when the magnetic field exceeded a certain value, i.e., approximately 1.5 T in this study. The mean diameter of the droplet-shaped Co-rich phases distributed in the matrix of the Cu-rich phase increased gradually with the magnetic field and increased rapidly at approximately 1.5 T. Moreover, it was speculated from the result of periodic laser heating that the marked change in the phase separation structures at approximately 1.5 T might be due to a convective transition from turbulent flow to laminar flow in the molten sample, where the time variation of temperature in the lower part of the electromagnetically levitated molten sample was measured when the upper part of the sample was periodically heated.