Compressive characteristics of bimodal aluminium matrix syntactic foams

Abstract

High performance metal matrix syntactic foams (MMSFs) have been produced by liquid state infiltration of AlSi12 alloy into two loosely packed sets of different nominal diameter (150 μm and 1500 μm) oxide hollow spheres (CHSs) and their mixed packs. The structure of the MMSFs has been studied by X-ray computer tomography and microscopy. The mechanical properties were mapped by compressive tests. The structural investigations showed proper infiltration. In the case of pure small and large CHS filler, the compressive tests revealed high strength levels all over the deformation of the materials up to 50% compressive strain, with the dominance (higher strength values) of the smaller CHSs filled MMSFs. In the case of bimodal CHS filling, the compressive features of the MMSFs have been mixed with two local peaks corresponding to the failure of the smaller and larger CHS filled MMSFs. Rule of mixtures is applicable to estimate the compressive strength.