Microstructure and properties of aluminum foam/aluminum sandwich prepared by brazing

The foam aluminum/aluminum sandwich was prepared by vacuum brazing with Al-Si as brazing filler. The microstructure of the sandwich panel was characterized by metallography, SEM morphology and EDS spectrum. Meanwhile the bending mechanical properties of the sandwich panels and the effects of the parameters of brazing on the microstructure and mechanical properties of the aluminum/aluminum alloy foam joints were analyzed. The results shown that the microstructure in the central zone of brazing seam was mainly composed of α (Al) solid solution, massive CaAl₂Si₂compound and skeletal CaAl₄ at the welding temperature 605~625℃ for 20 min. With the increase of the welding temperature, diffusion of the alloying elements was accelerated into the base metal, and the distribution of massiveCaAl₂Si₂ become more uniform. The toughness of the weld center was improved. When the welding temperature was 625℃, The highest strength up to 67.97MPa of the foam aluminum/aluminum sandwich were achieved.