单相高熵合金凝固过程中固液界面特性及行为

项目名称： 单相高熵合金凝固过程中固液界面特性及行为

项目编号： No.51471133

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 一般工业技术

项目作者： 王志军

作者单位： 西北工业大学

项目金额： 80万元

中文摘要： 由于具有高混合熵、高晶格畸变、缓慢扩散等新效应，且在某些特殊工作环境中具有重要的应用前景，高熵合金自一提出就引起了广泛的关注。凝固是高熵合金制备的关键环节,凝固过程的研究是高熵合金微观组织调控的基础，同时高熵合金的新效应也必为凝固理论带来新现象和新规律。然而，高熵合金凝固过程的研究并未得到足够重视，且已成为高熵合金进一步发展的瓶颈之一。本项目拟结合关键实验和理论计算分析，以高熵合金的凝固界面热力学特性及动力学行为为主线，完善高熵合金热力学数据库，建立适用于高熵合金的固-液界面结构模型及溶质截留模型，揭示高熵效应对相变驱动力、界面平衡溶质分配、界面能等热力学特性的影响机制，阐明缓慢扩散效应对溶质截留及界面形态演化等动力学行为的影响规律，明确不同凝固条件下高熵合金固-液界面演化动力学及微观组织选择规律，为实现高熵合金凝固微观组织的调控及高熵合金凝固理论的完善奠定基础。

中文关键词： 金属凝固；固液界面；高熵合金

英文摘要： High Entropy Alloys (HEAs) have drawn much attention recently because of their remarkable features, including high configurational entropy, severe lattice distortion and sluggish diffusion， and their potential applications in some special circumstances. On the one hand, solidification is the essential process during the preparation of HEAs and plays an important role in microstructure control. On the other hand, the new features of HEAs bring new phenomena and challenges to the existing solidification theory. Up to now, however, the solidification of HEAs causes less attention, which also limits the development of HEAs. In this proposal, we will investigate the solidification process of HEAs with emphasis on the solid-liquid interface from both thermodynamics and kinetics aspects. The thermodynamic model of HEAs will be evaluated to improve the thermodynamic database of HEAs. The solid-liquid interface model and solute trapping model suitable for HEAs will also be established. We will reveal the mechanisms of high entropy effect on the thermodynamic driving force, equilibrium solute partition and interface energy across the solid-liquid interface. The influence of sluggish diffusion on the solute trapping and interface morphology evolution will also be evaluated. The success of this proposal can supply theoretical explanation for the microstructure evolution in HEAs' solidification under various conditions and pave the way for the design of solidification microstructures.

英文关键词： Solidification;Solid/liquid interface;High entropy alloys