Production of graded aluminum foams via powder space holder technique

Aluminum open-cell foams with graded cell size and graded density were successfully fabricated by powder-space holder technique using spherical granulated carbamide as space holders. The results revealed that the technique was practically feasible. Compressive properties of the graded foams were studied being compared with their analogous non-graded foams. In both cases graded foams showed no prominence in comparison to their corresponding analogous foams, except for cell size-graded foam (SGF) which demonstrated a wider plateau region in the stress–strain curve, higher densification strain, and higher energy absorption efficiency in respect to those of analogous non-graded foams. Feasibility study to produce density graded foam (DGF) by NaCl spacer was also evaluated, using the same technique. It was shown that carbamide spacer was more feasible than NaCl spacer did in producing density graded foam.