Gradient regulation and compressive properties of density-graded aluminum foam.

Density-graded aluminum foams provide the possibility to further improve performance under static and dynamic loading. Tailoring and precise manipulating the graded structure is highly desired. Herein, we successfully prepared density-graded aluminum foam and investigated the effects of experimental parameters, i.e. cooling rate, growth rate, holding time, on the eventual density gradient. Microstructures of cell walls were found to vary with the distance away from cooling end. A numerical model coupling the foam melt growth and solidification was developed to predict the density gradient. Once the foaming agent content was high or the holding time was limited, the model predictions were highly accurate. Mechanical properties of density-graded aluminum foam were studied by quasi-static compressive tests. The relationship between compressive stress/strain curves and density distribution was established, which made the mechanical properties of density-graded aluminum foam more tailorable. [ABSTRACT FROM AUTHOR]