Aluminum foam is a lightweight material and has excellent shock-absorbing properties. Various properties of aluminum foam can be obtained by changing the base aluminum alloy. Multi-layer aluminum foam can be fabricated by varying the alloy type of the base aluminum alloy, but with different foaming temperatures, within a single aluminum foam to achieve multiple properties. In this study, we attempted to fabricate a two-layer aluminum foam with the upper layer of a commercially pure aluminum A1050 foam and the lower layer of an Al-Si-Cu aluminum alloy ADC12 foam by using an optical heating device that can heat from both the upper and lower sides. Two types of heating methods were investigated. One is to directly stack the A1050 precursor coated with black toner on top of the ADC12 precursor and to foam it from the top and bottom by optical heating. The other is to place a wire mesh between the ADC12 precursor and the A1050 precursor and place the A1050 precursor on the wire mesh, thereby creating a space between the precursors, which is then foamed by optical heating from the top and bottom. It was shown that both precursors can be foamed and joined, and a two-layer A1050/ADC12 foam can be fabricated for both types of heating methods. In the method in which two precursors were stacked and foamed, even if the light intensity of the halogen lamps on the top and bottom were adjusted, heat conduction occurred between the stacked precursors, and the foaming of each precursor could not be controlled, resulting in tilting of the joining interface. In the method of foaming using a wire mesh with a gap between two precursors, it was found that by adjusting the light intensity, the two precursors can be foamed almost simultaneously and achieve similar pore structures. The joining interface can also be maintained horizontally.
Keywords: aluminum alloy; cellular materials; composite; foam; joining; optical heating.