Syntactic foam core metal matrix sandwich composite: Compressive properties and strain rate effects

The present work is the first attempt to study metal matrix syntactic foam core sandwich composites. The sandwich is studied for microstructure and compressive properties at quasi-static and high strain rates. Under quasi-static compressive conditions, specimens were tested in the flatwise and edgewise orientations. The compressive strength, yield strength and plateau stress were higher in the flatwise orientation. Furthermore, both orientations for the sandwich composites showed a higher specific compressive strength and specific yield strength than the foam core alone. Failure initiated in the particles in the flatwise orientation, but in the carbon fabrics in the edgewise orientation. The results show that the fabric had a reinforcing effect under quasi-static conditions. The high strain rate (HSR) characterization was conducted in the strain rate range 525-845 s−1 using a split-Hopkinson pressure bar set-up equipped with a high speed image acquisition system. Within this strain rate range, the compressive strength of the sandwich is similar to that of the syntactic foam core alone. Upon review, the syntactic foam core metal matrix sandwich outperforms most of the syntactic foams in terms of energy absorption and compressive strength at comparable density levels.