Mechanical enhancement of aluminum foam via in situ interfacial bonding

Aluminum foam (AF) has extensive application prospects due to its high specific strength and specific energy absorption. However, low compressive strength and plateau stress of AF limit their total energy absorption. This study introduces a combined way of melt foaming and infiltration casting for fabricating bi-continuous interpenetrating porous composites (BIPCs), which formed partial metallurgical bonding interfaces while ensuring three-dimensional mechanical bond constraints. Four types of three-dimensional structures were designed to reinforce AF. Mechanical behavior of AF and the composites under quasi-static compression was analyzed by combining compressive tests and the finite element method (FEM). The results showed that all reinforcements can efficiently improve the energy absorption of composites by preventing the expansion of cracks in aluminum foam. The structure reinforced along the body diagonal and the path of the center lines connecting the three pairs of parallel surfaces of the cube exhibited the best mechanical properties, whose energy absorption, specific energy absorption and specific compressive strength were 9.58, 3.48 and 2.89 times greater than those of AF, respectively. The critical stress of the rods to buckling and stretching failure of the four configurations were calculated. Results showed that large critical stresses tended to appear in the 1/4 and 1/2 round rods, which revealed that the fracture failure easily occurred at the intersection edges of plane surface and curved surface of struts.