Compressive Properties of A356 Closed-Cell Aluminum Foamed with a CaCO3 Foaming Agent Without Stabilizer Particles

The A356 aluminum alloy foams were fabricated by the melt foaming method using a CaCO3 foaming agent without any stabilizer particle. The samples of different densities ranging from 0.32 to 0.46 g/cm3 (relative densities of 0.12–0.17, respectively) and cell sizes ranging from 1.5 to 3.1 mm were formed. The effect of foaming conditions such as CaCO3 amount, mixing and holding time on compressive strength and energy absorption behavior were investigated. Results show that the compressive properties of the aluminum foam are characterized by three deformation stages: linear elastic stage, plastic collapse stage and densification stage. Also, the compressive stress and energy absorption capacity increase as the relative density increases. But elastic modulus of the foamed aluminum with 3 wt% CaCO3 (relative density = 14%) is higher than others because its cell size distribution is more homogeneous than others. The compressive strength of aluminum foams without any stabilizer particles is comparable to the other researches for aluminum foams with stabilizer particles at the same density.