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

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.