Improving the Producibility and Predictability of Reactive Multilayer Joining

点击翻译按钮获取中文摘要

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.