Compressive properties of expanded glass and alumina hollow spheres hybrid reinforced aluminum matrix syntactic foams

Abstract

Expanded glass (EG) and alumina hollow spheres (HS) hybrid reinforced aluminum matrix syntactic foams and syntactic foams containing only a single reinforcement were prepared using the stir casting method. The volume fraction of reinforcements in the syntactic foam reached the maximum value by this production method in the available reports, i.e. 52.24%. No significant chemical reaction occurred between matrix and reinforcements. The quasi-static compressive properties of reinforcements and syntactic foams were tested. Regardless of the reinforcement type, the compressive properties of syntactic foams containing smaller reinforcements (diameter 2–3 mm) are higher than that of foams with 3–4 mm reinforcements. The compressive strength, plateau stress, stress drop, and energy absorption of hybrid reinforced syntactic foams decrease with the increase of EG content. The density and compressive properties of hybrid reinforced syntactic foams can be predicted using the rule of mixture and are in good agreement with the measured values. The syntactic foams exhibit brittle deformation characteristics and the crack propagation path depends on the EG content.