Reactive nanostructured foil used as a heat source for joining titanium

We have joined titanium alloy (Ti-6Al-4V) specimens at room temperature and in air by using free-standing nanostructured Al/Ni multilayer foils to melt a silver-based braze. The foils are capable of undergoing self-sustaining exothermic reactions and thus act as controllable local heat sources. By systematically controlling the properties of the foils and by numerically modeling the reactive joining process, we are able to conclude that the temperatures reached by the foils during reaction are critical in determining the success of joining when using higher melting temperature braze layers. (C) 2004 American Institute of Physics.