静电悬浮条件下液态合金的热物理性质与快速凝固研究

项目名称： 静电悬浮条件下液态合金的热物理性质与快速凝固研究

项目编号： No.51271150

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： 魏炳波

作者单位： 西北工业大学

项目金额： 83万元

中文摘要： 采用静电悬浮实验技术模拟空间环境条件，实现三元Ni基和Ti基合金熔体的深过冷与快速凝固。研究高压静电场中固态和液态合金的表面极化过程，探索静电感应对悬浮液滴运动形态、传热传质和晶体形核的作用机制。在静电悬浮状态下，系统地测定液态合金的表面张力、粘度、密度和扩散系数等热物理性质随过冷度变化规律，为定量研究快速凝固动力学获取必需的原始数据。重点研究静电场和强激光的耦合作用下深过冷三元合金中枝晶、共晶和包晶生长特征，实验确定单相和复相凝固组织发生形态演变的临界过冷度，揭示固/液界面高速运动与传热传质和溶质截留的本征关系。同时采用分子动力学和相场理论方法，对深过冷合金熔体的微观原子组态、宏观热物理性质和晶体形核与生长进行深入的数值模拟研究。在实验研究和理论分析的基础上，阐明三元单相和复相合金的快速凝固共性规律，并建立相应的组织形成理论模型。

中文关键词： 静电悬浮；热物理性质；深过冷；快速凝固；相分离

英文摘要： The containerless processing of liquid ternary Ni and Ti based alloys is accomplished by electrostatic levitation technique. This ensures the realization of high undercooling and rapid solidification. An experimental study will be conducted about the surface polarization process of both solid and liquid alloys. The influences of electrostatic induction on droplet oscillation, heat and mass transfer as well as crystal nucleation are to be explored during containerless processing. By taking full advantage of the electrostatically levitated state, systematic measurements are carried out about the thermophysical properties of substantially undercooled liquid alloys such as surface tension,viscosity, density and solute diffusivity. These physical parameters provide the indispensable original data for the further quantitative research of rapid solidification kinetics. The keynote of this project is focused upon the experimental investigations of rapid dendritic, eutectic and peritectic growth processes with the coupled effects of electrostatic field and intense laser. The undercooling thresholds for microstructural transitions are determined for both single phase and composite alloys, whereas the correlations of solid/liquid interface advancement with temperature and concentration fields as well as solute trapping are

英文关键词： electrostatic levitation；thermophysical property；liquid undercooling；rapid solidification；phase separation