Functionally graded metal syntactic foam: Fabrication and mechanical properties

Our manuscript on functionally graded metal syntactic foam has been published in Materials & Design as an open access article.

Abstract: In this research study a novel functionally graded metal syntactic foam (FG-MSF) was manufactured using ex- panded 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 per- lite (EP-MSF) and ZA27/activated carbon (AC-MSF) syntactic foam. The density ofthese 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 ofthe particle-matrix interfaces. The mechanical properties ofthe produced FG- MSFwere evaluated using quasi-static compression testing. The results showed that the deformationmechanism 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.

Impact of particle strength and matrix ductility on the deformation mechanism of metallic syntactic foam

Our manuscript has been accepted for publication in the  Journal of Alloys and Compounds. A free PDF can be downloaded until March 26, 2019.

Abstract: This paper presents a systematic study on the interaction between particle strength, matrix ductility and the deformation mechanism in metallic syntactic foam (MSF). Packed beds of near-spherical NaCl particles (ø2-2.8 mm) were infiltrated with liquid metal to produce the required samples. The brittle zinc alloy ZA-27 and ductile Aluminium (99% Al) were used as matrix materials. NaCl particles were retained inside half of these samples to replicate MSF containing high-strength particles. NaCl was leached from the remaining samples to investigate MSF with weak particles. This procedure ensured that all samples had a near-identical matrix geometry and microstructure, thus isolating the effect of particle strength. Quasi-static compression tests were conducted and significant changes in the deformation behaviour were observed. Samples containing NaCl particles deformed in a shear-band dominated mode, whilst the ductile foam underwent layer-by-layer deformation.