Dendritic growth velocities in an undercooled melt of pure nickel under static magnetic fields: A test of theory with convection
Dendritic growth velocities in an undercooled melt of pure nickel under static magnetic fields: A test of theory with convection
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DOI：
10.1016/j.actamat.2015.10.014
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发表时间：
2016-01-15
期刊：
影响因子：
9.4
通讯作者：
Galenko, Peter K.
中科院分区：
文献类型：
--
作者：
Gao, Jianrong;Han, Mengkun;Galenko, Peter K.
用高速相机测量了6T恒磁场作用下过冷纯镍熔体中的枝晶生长速度。在低磁场下，120K以下过冷区的生长速度被抑制，但在强磁场下，生长速度逐渐恢复。这种逆行行为源于熔体中两种相互竞争的磁流体动力学，对于更高的过冷度，这种行为变得难以区分。测量的数据被用来检验最近的有对流的枝晶生长理论。通过假设随磁场变化的流速，得到了一个合理的一致性。结果表明，该理论还可以解释在正常重力和微重力条件下纯丁二腈中的枝晶生长动力学数据。这些试验证明了该理论的有效性，该理论为具有对流的纯物质的枝晶生长动力学提供了真实的描述。0 2015 Acta Materialia Inc.由爱思唯尔有限公司出版。保留所有权利。
Dendritic growth velocities in an undercooled melt of pure nickel under static magnetic fields up to 6 T were measured using a high-speed camera. The growth velocities for undercoolings below 120 K are depressed under low magnetic fields, but are recovered progressively under high magnetic fields. This retrograde behavior arises from two competing kinds of magnetohydrodynamics in the melt and becomes indistinguishable for higher undercoolings. The measured data is used for testing of a recent theory of dendritic growth with convection. A reasonable agreement is attained by assuming magnetic fielddependent flow velocities. As is shown, the theory can also account for previous data of dendritic growth kinetics in pure succinonitrile under normal gravity and microgravity conditions. These tests demonstrate the efficiency of the theory which provides a realistic description of dendritic growth kinetics of pure substances with convection. 0 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.