Effect of processing parameters on cell structure of an aluminum foam

A closed cell aluminum foam with the same composition but different cell sizes and structures was prepared by changing air injection rate and impeller speed during foaming process to study the influence of air injection rate and impeller speed on cell structure. The foams prepared under the foaming conditions are characterized as roughly equiaxed polyhedral cells with density range of 0.1–0.22 g/cm3 and cell diameter of 4–11 mm with different cell wall thickness and Plateau border size. Cell size of the aluminum foam is increased with increasing air injection rate, and higher impeller speed results in a much smaller cell size at given air injection rate. Cell wall thickness and Plateau border size of the aluminum foams are decreased with the increase in cell size. Moreover, the higher impeller speed produces smaller size of the foam cells with thicker cell wall and Plateau border size, resulted in higher density foam in contrast to the foam with the same cell size prepared at lower impeller speed.