CAREER: Fabrication & Characterization of Reactive Multi- layer Foils for Joining Application and Development of a Database for Classroom Demonstrations

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9702546 Weihs This CAREER grant explores a relatively new phenomena in nanoscale multilayer materials: self-propagating, exothermic reactions. Using free-standing multilayer foils that are sputter deposited, the velocities and temperatures of the self-propagating reactions are quantified using optical techniques. The thermodynamic driving forces are measured using calorimetry techniques, and resulting microstructures identified using electron microscopy and X- ray diffraction. The impact of structural and physical parameters on the ignition, velocity, and temperature of the reactions are investigated, and the resulting information used to develop models that aid in understanding the reactions and in predicting material properties. The educational program is designed to strengthen the materials science education infrastructure by developing a national database for classroom demonstrations. This educational program provides the design of a National Data Base for Classroom Demonstrations in Materials Science. The database could be linked to NSF's home page to permit quick access to ideas, instructions, and information for classroom demonstrations. It could include descriptions, pictures and videos of exciting new demonstrations in materials science. %%% Novel exothermic reactions have been demonstrated in thick, free-standing multilayer foils. They ignite at room temperatures with a simple spark, travel at speeds greater than 10m/s, and reach temperatures above 1500 C. As free- standing foils they offer the ability to generate heat rapidly and locally, providing new opportunities for joining materials. ***