Solid-state diffusion bonding of closed-cell aluminum foams

Solid-state diffusion bonding (DB) was demonstrated for joining closed-cell aluminum foams (ALPORAS). A superplastic 5083 aluminum alloy sheet was inserted between the foams to assist the DB process. Microscopic observation revealed that the cell wall of the foams penetrated into the 5083 alloy sheet and their boundary partly disappeared. Energy dispersion X-ray spectrometer (EDS) confirmed the diffusion of magnesium element from the 5083 alloy to the aluminum foam regions. The bonding strength was evaluated by four-points bending tests. The obtained flexure stress was about 50% of the original foam at room temperature and was more than 60% at 423 K. The advantage of the DB process in the high temperature applications was discussed comparing with the adhesive bonding of aluminum foams.