Controlling solute channel formation using magnetic fields
Controlling solute channel formation using magnetic fields
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DOI：
10.1016/j.actamat.2023.119107
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发表时间：
2023-09
期刊：
影响因子：
9.4
通讯作者：
Xianqiang Fan;N. Shevchenko;C. Tonry;S. Clark;R. Atwood;S. Eckert;K. Pericleous;P. D. Lee;
中科院分区：
文献类型：
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作者：
Xianqiang Fan;N. Shevchenko;C. Tonry;S. Clark;R. Atwood;S. Eckert;K. Pericleous;P. D. Lee;
溶质通道的形成在一系列过程中引入了成分和微观结构的变化，从金属合金凝固到海洋和水库流动中的盐指。施加外部磁场与固体/液体界面处的热电流相互作用，产生额外的流场。这种热电（TE）磁流体动力学（TEMHD）效应可以影响溶质通道的形成，通过最近引起越来越多的关注的机制。为了研究这一现象，我们结合原位同步辐射X射线成像和基于格子-Boltzmann的数值模拟来研究TEHD下的流动和溶质输运特性。观察表明宏观TEMHD流出现在凝固前沿之前，再加上糊状区内产生的微观TEMHD流是控制羽流迁移和通道偏差的主要机制。两个TE制度被发现，每个独特的机制，占主导地位的流动。此外，我们表明，晶粒取向修改溶质流动通过各向异性渗透率。这些见解导致了一个提出的战略，用于生产溶质通道自由凝固使用时间调制磁场。
Solute channel formation introduces compositional and microstructural variations in a range of processes, from metallic alloy solidification, to salt fingers in ocean and water reservoir flows. Applying an external magnetic field interacts with thermoelectric currents at solid/liquid interfaces generating additional flow fields. This thermoelectric (TE) magnetohydrodynamic (TEMHD) effect can impact on solute channel formation, via a mechanism recently drawing increasing attention. To investigate this phenomenon, we combined in situ synchrotron X-ray imaging and Parallel-Cellular-Automata-Lattice-Boltzmann based numerical simulations to study the characteristics of flow and solute transport under TEMHD. Observations suggest the macroscopic TEMHD flow appearing ahead of the solidification front, coupled with the microscopic TEMHD flow arising within the mushy zone are the primary mechanisms controlling plume migration and channel bias. Two TE regimes were revealed, each with distinctive mechanisms that dominate the flow. Further, we show that grain orientation modifies solute flow through anisotropic permeability. These insights led to a proposed strategy for producing solute channel-free solidification using a time-modulated magnetic field.