热电磁流动和热电磁力对液/固界面稳定性和枝晶生长的影响

项目名称： 热电磁流动和热电磁力对液/固界面稳定性和枝晶生长的影响

项目编号： No.51271109

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 一般工业技术

项目作者： 李喜

作者单位： 上海大学

项目金额： 80万元

中文摘要： 由于塞贝克效应，定向凝固过程中在液/固界面和枝晶间形成热电流。施加磁场后，磁场和热电流相互作用在液相和固相形成热电磁力。此力作用于液/固界面和枝晶臂上，并在液相诱发热电磁流动。本项目拟研究磁场作用下在定向凝固过程中热电磁流动和热电磁力及其对液/固界面稳定性和枝晶生长影响。首先从理论分析和数值模拟的角度上探明不同尺度上的热电磁流动及固相所受热电磁力分布和大小；及其随磁场强度和温度梯度的变化规律。进而以Al基和Ni基单相合金为研究对象进行磁场（强/弱）下定向凝固实验，并应用同步辐射实时观测，从实验角度上搞清磁场矢量和温度矢量对液/固界面和枝晶形貌影响规律。通过以上研究，探明热电磁流动和固相受热电磁力对液/固界面稳定性和枝晶生长的影响规律。最终达到深化液相流动和固相受力下液/固界面稳定性和枝晶生长理论的目的；并为固相受力下"Asaro-Tiller-Grinfield不稳定性理论"提供实验证据。

中文关键词： 热电磁流动；热电磁力；枝晶；凝固界面；定向凝固

英文摘要： Due to Seebeck effect, the thermoelectric current is created on the liquid/solid interface and the interdendrite during the directional solidification. When the magnetic field is applied, the interaction between the thermoelectric current and the magnetic field creates a thermoelectric magnetic force in the liquid and solid. This force will act on the solid near the liquid/solid interface and the dendrite arm on the one hand, and induce the convection of the liquid on the other hand. This project aims to investigate the effect of a high magnetic field on the liquid/solid interface stability and the dendrite growth. Firstly, the thermoelectric magnetic convection with different scales and the effect of the magnetic field intensity and temperature gradient on them have been investigated theoretically and numerically. Then, the effect of the magnetic field intensity and temperature gradient on the liquid/solid interface shape and dendrite morphology will be studied during directional solidification experimentally. Moreover, the synchrotron radiation will be applied to observe in situ the development of the interface shape and dendrite morphology under the thermoelectric magnetic convection and force. Through above investigations, the effect of the thermoelectric magnetic convection and thermoelectric magnetic for

英文关键词： Thermoelectric magnetic convection；Thermoelectric magnetic force；Dendrite；Solidification interface；Directional solidfication