层状金属复合材料物理外场作用下界面调控机理与性能研究

Laminar metal composite is a new type of structure and function material combined by two or more metal materials with different performance. This kind of materials has fine designability and combination property, which was widely used in aerospace, oceaneering, automobile industry and so on. In recent years, the research and development of this material has become an important research aspect. The interface is connective bond of different metal materials for laminar metal composite. Therefore, the study of interface formation mechanism is the key issue to prepare fine laminar metal composite. Three kinds of typical compound interfaces included copper/aluminium, magnesium/aluminium with chemical reaction and aluminium/aluminium without chemical reaction were chosen in this project. The thermodynamics and dynamics problems about nucleus formation and grain growth near the interface in physical field (low frequency rotating magnetic field and power ultrasonic field) were studied by the analysis of solidification structure, element distribution, mechanics performacce testing. In addition, the influencing mechanism of interface structure and mechanical property by physical field was also investigated. On this basis, the continuous casting by physical field and rolling method of preparing laminar metal composite was proposed, providing high-quality and low-valent laminar metal composite for industrial development of our country.

层状金属复合材料是将两种或多种不同性能的金属材料采用一定的加工工艺复合在一起的一种新型的结构和功能材料，具有较强的可设计性和良好的综合性能，因此被广泛应用于航天航空、海洋工程和汽车工业等领域，目前已成为新材料研究开发的重点方向之一。对于层状金属复合材料，界面是两种不同金属材料连接的纽带，直接影响其结合效果，研究界面形成机制是获得良好层状金属复合材料最关键的问题。本项目主要选取有化学反应的铜/铝、镁/铝层状复合材料以及无化学反应的铝/铝层状材料三种典型的复合界面为对象，通过对界面附近凝固组织结构、元素分布、力学性能测试的分析，研究了物理外场（主要为低频旋转磁场及功率超声场）作用下界面处晶核形成、晶粒生长的热力学和动力学问题，以及物理外场对界面结构和力学性能的影响机制。在此基础上，提出具有自主知识产权的层状金属复合材料物理外场连铸及轧制新方法，为我国工业发展提供高质、低价的层状金属复合材材料。

本项目主要选取有化学反应的铜/铝、镁/铝层状复合材料以及无化学反应的铝/铝层状材料三种典型的复合界面为对象，通过对界面附近凝固组织结构、元素分布、力学性能测试的分析，研究了物理外场（主要为低频旋转磁场及功率超声场）作用下界面处晶核形成、晶粒生长的热力学和动力学问题，以及物理外场对界面结构和力学性能的影响机制。研究发现，当两种金属为无反应的同种金属时，其界面结合是熔合和扩散双重作用机制，当两种金属为有反应的异种金属时，界面处流体的流动会加速该反应的进行，如交变旋转磁场制备5056/AZ91时，AZ91熔体的强迫运动加速对5056凝壳的冲刷，最终使得从界面到心部均为Mg2Al3铝镁间金属化合物。另外在功率超声作用下，空化效应的作用有利于物质表面氧化膜的破坏，有利于新鲜的材料表面之间直接接触，最终通过有限的化学反应复合实现界面结合。最后在此基础上，提出了具有自主知识产权的层状金属复合材料物理外场连铸及轧制新方法，为我国工业发展提供高质、低价的层状金属复合材材料。