多元单相合金的超声悬浮与快速凝固研究

项目名称： 多元单相合金的超声悬浮与快速凝固研究

项目编号： No.51301138

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 一般工业技术

项目作者： 闫娜

作者单位： 西北工业大学

项目金额： 26万元

中文摘要： 超声悬浮技术是实现合金熔体深过冷与快速凝固的有效途径之一，为开展极端非平衡条件下材料合成与制备研究提供了有利条件。超声场中液态合金特有的振荡和流动形态使多元单相合金在悬浮无容器状态下的凝固过程呈现出新现象和新规律。本项目拟选取三~五元Ni基单相合金作为研究对象，将超声悬浮与激光熔凝和高速摄像等实验方法相结合，系统开展深过冷条件下的快速凝固机理研究。重点探索超声悬浮状态下合金熔体的不同运动模式对传热传质、过冷能力和晶体形核的作用机制。实验测定多元合金熔体中枝晶生长速度随过冷度变化特征，同时采用相场理论方法对微观组织演化进行模拟计算研究。通过深入分析快速凝固过程中溶质截留效应，研究不同溶质元素间的交互作用规律。系统揭示超声悬浮状态下"熔体运动-内部对流-枝晶生长-凝固组织"之间的本征关系，阐明多元单相合金无容器快速凝固的共性规律，促进多元合金非平衡凝固理论的进一步发展。

中文关键词： 超声悬浮；多元合金；枝晶生长；溶质截留；力学性能

英文摘要： Acoustic levitation is an effective method to realize high undercooling and rapid solidification of alloy melts, which can provide convenience for the investigation of material synthesis and preparation under nonequilibrium condition. The rapid solidification process of multicomponent single phase alloy will present a new phenomena and new characteristics due to the droplet oscillation and internal flow under ultrasonic field. Here, the acoustic levitation, laser melting and high speed camera are applied to the investigation of rapid solidification process of undercooled multicomponent Ni-based single phase alloy. The influences of acoustically levitated state on droplet oscillation, heat and mass transfer， undercoolability as well as crystal nucleation are to be explored during containerless processing. By taking full advantage of such method, systematic measurements are carried out on the dendritic growth of substantially undercooled liquid alloys. Meanwhile, the phase field theory method is employed coupled with the internal flow to carry out the numerical simulations on the microstructure evolution and solidification process of highly undercooled liquid alloys. The interaction between different solute elements is studies combined with the microstructure evolution and solute distribution of single phase alloy

英文关键词： Acoustic levitation；multicomponent alloy；dendritic growth；solute trapping；mechanical property