Boosting energy absorption performance of aluminum matrix syntactic foam with carbon coated glass cenospheres

In this study, glass cenospheres are coated with resorcinol/formaldehyde resin in an alkaline solution, and the polymer layer is subsequently transformed into carbon shell by pyrolysis. Because carbon is a strong and light-weight material, the resulting aluminum matrix syntactic foam reinforced with carbon coated glass cenospheres shows low density of 1.35 g cm⁻³, and high energy absorption capacity of 80.3 MJ m⁻³. The excellent energy absorption properties are ascribed to the conformal carbon shell that can disperse stress, leading to high compressive strength of the foam. The improved wettability of filler surfaces by liquid metals during pressure infiltration casting is verified using both optical and electron microscopy. In addition, XRD results suggest that no obvious interfacial reactions happen during the preparation of foam.