Effect of dual-size cell mix on the stiffness and strength of open-cell aluminum foams

The mechanical properties of open-cell aluminum foams with dual-size cell distributions produced by infiltration method are measured. It is found that the relative density decreases when small cells (∼0.5 mm) are mixed into foams with large cells (∼2.5 mm). The open-cell aluminum foam mixed with small cells in low volume fraction show remarkable increase in stiffness and strength. However, the stiffness and strength of foams with high volume fraction of small cells degrade. The effect of multi-size cell mix on the performance of open-cell aluminum foams is investigated using finite element analysis of 2-D (hexagonal honeycomb) idealized cellular material models. The mechanism how cell size distribution influences the stiffness and strength is presented and discussed.