Abstract
One of the practical applications of porous aluminum is the core material for panel/foam sandwich structures. To manufacture the foam/panel sandwich structure by a powder processing route, a sheet type precursor is essential. Therefore, a foaming behavior of aluminum sheet precursor (pure Al, 6061Al and Al-7Si) was examined. The foaming behavior was examined by the projected area of a precursor recorded by two video cameras from horizontal (lateral-side observation) and vertical (top-surface observation) directions. Average diameters and vertical/horizontal Feret diameter ratios were used to evaluate pore morphology. Free foaming behavior of the sheet type precursors was extremely unidirectional along the compression direction of the rolled precursor. With regard to pure aluminum and 6061Al precursors, the pore morphology at the early stage of foaming was extremely anisotropic (flat shape), while the pore morphology became spherical when the specimen reached to the maximum expansion. As for the Al-7Si precursors, such flat anisotropic pores were not observed even at the early stage of foaming.
