Functionally Graded Syntactic Foams with Layers of Dissimilar Metallic Matrices

This research study introduces a novel functionally graded metal syntactic foam. Counter-gravity infiltration casting is employed to manufacture MSF layers with dissimilar metallic matrices. Each layer combines expanded perlite particles with a different matrix alloy, i.e., ZA27 or pure aluminum. Dissimilar MSF layers are combined either during casting or using different joining techniques following manufacturing. The dissimilar matrices introduce a controlled gradient of the physical and mechanical properties of the resulting functionally graded foam material. Quasi-static compression testing shows that the initial deformation is controlled by the weaker aluminum syntactic foam layer. Following partial densification of this layer, deformation transitions toward the layer containing the higher strength ZA27 matrix alloy.