Preparation and characterization of light weight aluminum matrix syntactic foams with high energy absorbing capacity

Aluminum matrix syntactic foams (AMSFs) with low density are widely utilized in the field of impact resistance owing to their high energy absorbing properties. In present study, to further lower the density and improve the energy absorption of AMSFs, a low-temperature micro-pressure infiltration was utilized to avoid destroying the hollow structure and a bi-continuous structure was designed to increase the energy absorbing interface and improve the deformation behavior. Results show that the hollow sphere content was up to 65% and a breakage rate was below 4% in the composites. Meanwhile, the composites displayed a rather low density of 1.23–1.41 g cm⁻³, a high compressive strength of 83.96–243.31 MPa, and an excellent energy absorbing capacity of 38.07–99.51 MJ m⁻³ under quasi-static loading, which outperforms the most advanced AMSFs as reported in the literatures. With the increase of strain rate, the composites showed higher plateau stress and energy absorbing capacity under dynamic loading. The energy was absorbed by shear deformation of cenospheres and interfacial tearing between cenospheres and aluminum matrix. A unique “fracture ring” was observed in bi-continuous structure preventing crack growth.