Fabrication of Composite of Al-Si-Cu Alloy Foam Core Surrounded by Pure Aluminum Foam and Its Compression Properties

Aluminum (Al) foam fabricated using ADC12 Al-Si-Cu alloy has high plateau stress. However, the plateau stress in an impact test of ADC12 Al foam was lower than that in a static test because small fragments of the Al foam caused localized brittle fracture and dispersed. In this study, to prevent brittle fracture and the drop in plateau stress, fabrication of a composite of ADC12 foam core surrounded by A1050 foam was attempted. In the fabrication process, an A1050 precursor was foamed in an electric furnace followed by foaming of an ADC12 precursor in a square hole machined at the center of the A1050 foam using two different methods of heating in an electric furnace and optical heating. The fabricated composites were observed through x-ray computed tomography (CT). Hardly any gaps were observed at the interface between the A1050 and ADC12 foams in the composites. Moreover, drop weight impact tests of the composites were conducted to evaluate the plateau stresses. It was found that the estimation method allowed the plateau stresses to be evaluated within an error of ± 20% based on the mean compressive stress in the cross section of a maximum-porosity perpendicular to the loading direction.