Functionally graded metal syntactic foam: fabrication and mechanical properties

In this research study a novel functionally graded metal syntactic foam (FG-MSF) was manufactured using expanded perlite and activated carbon particles. A tailored arrangement of these fillers was infiltrated with ZA27 alloy in a single-step process. The structure of the FG-MSF contained two individual layers: ZA27/expanded perlite (EP-MSF) and ZA27/activated carbon (AC-MSF) syntactic foam. The density of these FG-MSFs varied between 2.11 and 2.15 g·cm⁻³. Microstructural studies confirmed that no relevant chemical reaction occurred within the foam, in particular in the vicinity of the particle-matrix interfaces. The mechanical properties of the produced FG-MSF were evaluated using quasi-static compression testing. The results showed that the deformation mechanism of the FG-MSF is a mixed mode and varies between the two different filler layers. The energy absorption of the FG-MSF sample was increased compared to uniform syntactic foams containing only a single particle filler.