Variation of quasi-static and dynamic compressive properties in a single aluminium foam block

Abstract

The variation of the structural and compressive properties through a single rectangular closed-cell aluminium alloy foam block prepared by the powder-compact foaming technique was evaluated using quasi-static and dynamic loading conditions. For this study, this foam block was cut into identical representative foam cubes in three horizontal layers. Both quasi-static and dynamic compression tests were carried out on foam specimens in two orientations (parallel and perpendicular) related to foaming directions. The properties of these cubic representative specimens were also compared to integral-skin foam cubes of the same dimensions prepared using the same foaming temperature. The results showed that a large size variation of cellular pores with irregular cell shape is observed within the large foam block in height and width, due to the non-uniform foam growth. The variation of the properties is associated with the processing of the foams. Additionally, the relation between pore size, density and compressive properties has been studied. The results also show that the effect of the structural imperfections and defects on the compressive response is more pronounced for foams without skin. This is manifested in a higher scatter of the stress plateau. The results also demonstrate that the compressive properties and the energy absorption capabilities increase with the density and the strain rate. Such higher energy absorption capability during dynamic compression is beneficial for impact energy absorbing structures. Furthermore, the advantages of the application of integral-skin foam are demonstrated.