微/纳米颗粒对复杂相分离体系凝固组织的调控机制

项目名称： 微/纳米颗粒对复杂相分离体系凝固组织的调控机制

项目编号： No.51301139

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： 臧渡洋

作者单位： 西北工业大学

项目金额： 26万元

中文摘要： 通过在稳定、亚稳和模拟合金三类相分离体系中主动引入微/纳米尺度的固体颗粒，探索颗粒与合金熔体的浸润性，研究颗粒对合金熔体温度场、溶质浓度场的影响规律，揭示颗粒对初生固相、第二相液滴的诱发形核机制。利用落管、单辊急冷和熔融玻璃等实验手段实现合金熔体在不同物理条件下的相分离与凝固，研究固体颗粒、溶质分布规律以及两者之间的竞争机制，阐明合金凝固组织演变规律，揭示固体颗粒性质、颗粒引入方式等因素对凝固组织的影响机制。利用透明模拟合金进行实时观测，研究固体颗粒对固/液界面形态及其迁移速度的调控作用，探索其在液/液界面的吸附机理。同时结合相场模拟，深刻揭示固体颗粒与固/液、液/液界面的相互作用机制，建立"颗粒/界面相互作用－液相分离－凝固组织演变"的内在关系，最终阐明固体颗粒对复杂难混溶合金体系液相分离与凝固组织的调控规律，为该类合金的均质化制备提供新的思路。

中文关键词： 润湿；形核；相分离；液滴；液-液界面

英文摘要： The preparation of homogenous immiscible alloy without the formation of macroscopic segregation is quite a challenge due to the occurrence of liquid-liquid phase separation when the alloy melt falls into the liquid immiscibility gap. In this project, we propose a novel approach to obtain homogenous microstructure by tuning the liquid phase separation and microstructural evolution through introducing micro/nano-sized solid particles into the alloy melt. We will study the phase separation and solidification of three types of immiscible systems: Al-Pb monotectic alloy, metastable immiscible Co-Ni-Cu alloy and transparent H2O-SCN system. The introduced solid particles include SiC, Al2O3 and SiO2 particles. The techniques of drop tube, melt spinning and glass fluxing will be applied to obtain different physical conditions for solidification, such as different cooling rate and temperature gradient. The wettability of particles with the alloy melt will be studied. How the particles influence the temperature and solute fields and induce the nucleation of solid phase and L2 droplet will be clarified. The solidification rate versus undercooling will be measured experimentally. The microstructural evolution and the redistribution of particles will be researched by microstructure analysis of the final solidified samples. T

英文关键词： Wetting；Nucleation；Phase separation；Droplet；Liquid-liquid interface