Improving the Producibility and Predictability of Reactive Multilayer Joining

这个项目是一个实验和计算相结合的努力，旨在提高这个连接过程的可生产性和可预测性。反应性多层箔是一种新型的工程材料，可作为局部热源用于连接。这些多层箔由数百个纳米级层组成，这些层在混合热较大的元素（如Al和Ni）之间交替存在。自传播反应可以在室温下在这些箔中开始，并且反应性质可以通过改变箔的组成和各层的厚度来控制。通过在两个钎焊层和两个组件之间放置一个反应性箔并启动反应，来自箔的热量熔化了钎焊层并连接了组件。这种新的连接方法不需要真空炉，并且加热非常局部，限制了被粘合部件所看到的温度。这两个优点为连接温度敏感部件和不同材料（如金属和陶瓷）开辟了新的可能性。在计算上，本研究旨在分析热损失的影响，预测钎焊层的熔化，以及焊接部件的温度演变。预测将根据实验测量进行验证，然后应用于优化反应连接应用的设计。所得到的接头的物理性能和微观结构也将被表征。结合机械特性和数值预测，将提供将这种新连接技术插入各种制造应用所需的基本工具。预计本研究将对产业加盟运作及女高中学生、本科生及研究生的教育经验带来显著的改变。

This project is a combined experimental and computational effort that aims at improving the producibility and predictability of this joining process. Reactive multilayer foils are a new class of engineered materials that can be used as local heat sources for joining. These multilayer foils are comprised of hundreds of nanoscale layers that alternate between elements with large heats of mixing, such as Al and Ni. Self-propagating reactions can be initiated in these foils at room temperature, and the reaction properties can be controlled by varying the foil composition and the thickness of individual layers. By placing a reactive foil between two braze layers and two components and initiating the reaction, heat from the foil melts the braze layers and joins the components. This new method of joining requires no vacuum furnace and, with very localized heating, limits the temperature that is seen by the bonded components. Both advantages open new possibilities in the joining of temperature-sensitive components and of dissimilar materials like metals and ceramics. Computationally, this research aims to analyze the effect of heat losses, predict the melting of braze layers, and the evolution of temperature in the bonded components. Predictions will be validated against experimental measurements and then applied to optimize the design of reactive joining applications. The physical properties and microstructure of the resulting joints will also be characterized. Combined, the mechanical characterizations and numerical predictions will provide the fundamental tools that will be needed to insert this new joining technology into various manufacturing applications.It is expected that this research will lead to significant changes in industrial joining operations and to educational experiences for high school students from a woman's high school as well undergraduate and graduate students.