Reactive Multilayer Joining of SiC and Ti

This SBIR Phase I project introduces a new technology for joining components exhibiting large mismatch in coefficients of thermal expansion. The proposed technology is a reactive joining process that uses reactive multilayer foils as local heat sourcesfor melting brazes or solders. The foils are a new class of nano-engineered materials, in which self-propagating exothermic reactions can be ignited at room temperature with a spark. By inserting a multilayer foil between two braze (or solder) layers andtwo components, heat generated by the reaction in the foil melts the braze and consequently bonds the components. This new method of joining eliminates the need for a furnace and, with very localized heating, avoids thermal damage to the components. Thereactive bonding process is more rapid than competing technologies, and results in strong and cost-effective joints. Phase I effort will: (1) establish the feasibility and effectiveness of this joining method to produce large-area, 4 in. x 4 in., jointsbetween plates of Ti-6-4 and SiC, (2) develop and validate a design model for predicting heat transport and braze melting during the reactive joining process, and (3) demonstrate that the strength of the resulting joints are two times higher than bestepoxy joints. Successful development of reactive multilayer joining, and its adaptation to the joining of SiC and Ti-6-4 will not only enhance the performance of advanced ceramics in armor applications, but it will also open new opportunities forindustrial joining, mounting and assembly applications.