强磁场下深过冷Cu-Co、Al-Bi难混溶合金的形核、生长及凝固组织演变行为研究

项目名称： 强磁场下深过冷Cu-Co、Al-Bi难混溶合金的形核、生长及凝固组织演变行为研究

项目编号： No.51501036

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 一般工业技术

项目作者： 张义坤

作者单位： 上海大学

项目金额： 21万元

中文摘要： 由于难混溶合金在工业上具有非常重要的应用价值而成为材料科学领域的研究热点之一，同时强磁场作为一种极端手段可有效地调控材料在凝固过程中的组织结构进而提高其相关性能。本项目拟选择具有亚稳溶解度间隙的Cu-Co和稳定溶解度间隙的Al-Bi难混溶合金为模型合金，采用超导强磁场和深过冷快速凝固相结合对两种合金的形核动力学及相关参数进行系统研究；在此基础上，结合高速摄影技术对合金过冷熔体的枝晶生长速率进行原位观测；并利用SEM/EDS/EBSD等对合金及弥散相液滴的微观组织进行表征；最终建立磁场强度-形核动力学及相关参数-生长动力学-弥散相液滴尺寸、成分分布之间的定量关系。旨在揭示强磁场下难混溶合金的形核、生长过程与最终的凝固组织之间的内在关联，为难混溶合金的组织优化及性能调控到工业应用提供新的数据和思路。

中文关键词： 偏晶合金；强磁场；形核；深过冷；凝固组织演变

英文摘要： Investigation of the immiscible alloys becomes one of the hottest topics in the field of material due to its great potential application in the engineering. The high magnetic field as an extreme condition can adjust the microstructure during solidification and promote the related properties of the materials. The present research will choose the Cu-Co (with a metastable miscibility gap) and Al-Bi (with a stable miscibility gap) immiscible alloys as modal alloys, the nucleation kinetics and related parameters of the two alloy systems will be systematically investigated by using a combination of a superconducting high magnetic field and glass fluxing methods. The crystallization process of undercooled Cu-Co and Al-Bi alloys will be in-situ observed using a high-speed camera. The microstructure of alloys as well as the particle size distribution, composition and substructure will be systematically studied by means of SEM, EDS and EBSD methods. A quantitative relationship between magnetic fields, nucleation kinetics and related parameters, growth kinetics, and droplet size distribution and composition will be established based on the experimental results and related theory. The inherent correlation between nucleation, growth and phase evoluation in immiscible alloys during solidification will be clarified. The present research may provide some new data and methods to promotion of microstructure and related property modulation for industrial application of immiscible alloys.

英文关键词： Monotectic alloy;High magentic field;Nucleation;Undercooling;Microstructure evolution