Improving the Producibility and Predictability of Reactive Multilayer Joining

该项目是一项实验和计算相结合的工作，旨在提高这一加入过程的可生产性和可预测性。反应性多层铝箔是一种新型的工程材料，可作为局部热源进行连接。这些多层箔由数百个纳米级的层组成，这些层在具有大混合热的元素之间交替，如铝和镍。在室温下可以在这些箔中引发自蔓延反应，并且可以通过改变箔的组成和各层的厚度来控制反应性质。通过将反应箔放置在两个钎焊层和两个组件之间并引发反应，来自箔的热量熔化钎焊层并将组件连接在一起。这种新的连接方法不需要真空炉，并且通过非常局部的加热，限制了粘合部件的温度。这两个优点都为连接温度敏感部件以及金属和陶瓷等不同材料开辟了新的可能性。在计算上，本研究的目的是分析热损失的影响，预测钎焊层的熔化，以及焊接部件中温度的演变。预测将与实验测量结果进行验证，然后应用于反应性连接应用的优化设计。还将对所得到的接头的物理性能和微观结构进行表征。结合机械特性和数值预测，将提供将这种新的连接技术应用于各种制造应用所需的基本工具。预计这项研究将导致工业连接操作的重大变化，并为女子高中的高中生以及本科生和研究生带来教育经验。

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.