Multilayer reactive foils: Fabrication, reaction characterization, and room-temperature joining

The self-propagating reactive multilayer foils studied here were composed of alternating nanoscale layers of Al and Ni. The reactions associated with these foils can reach temperatures well over 1600°C with propagation velocities one the order of 1 to 10 m/s.; In order to characterized these reactions, a high spatial resolution (50 micron), high temporal resolution (25 microsecond) and high temperature resolution ratio pyrometer with a range of 900°C to 2000°C, was designed and assembled. The pyrometer was optimized for use with the self-propagating reactive foil systems and was used in conjunction with an apparatus for measuring the propagation velocity of these reactive foils.; The custom velocity and temperature devices were used to analyze the interrelationships between reaction velocity, maximum temperature, and activation energy in the Al-Ni reactive foil system. The results of this study indicate that final temperature and layer thickness may have opposing influences on reaction rate.; The process of joining SiC to Ti-6-4 was investigated from the standpoint of using reactive foils as an in-situ heat source. Advances in reactive foil deposition techniques were made to facilitate the fabrication of thick foils (>100 micron). Room temperature reactive foil joining with no external heat source was demonstrated and preliminary studies on the substantial bond strength were performed.; Finally, an investigation into the feasibility of fabricating reactive foils from layers of metal sheet was performed. The combined techniques of swaging and rolling were shown to be a promising method for the scale-up of reactive foil production, and reactive foils with properties similar to those of vapor deposited materials were be obtained via this process.