Al matrix syntactic foam fabricated with bimodal ceramic microspheres

The energy absorption capability of cellular solids is determined by their plateau strength and onset strain of densification, which in turn are dependent upon their porosity. Metal matrix syntactic foams fabricated with ceramic microspheres of a single size range have a nearly fixed porosity and thus have a limited variability in energy absorption. This paper fabricates Al matrix syntactic foams with monomodal or bimodal ceramic microspheres and compares their mechanical properties. The syntactic foams with bimodal ceramic microsphere have up to 10% higher porosity, which leads to 8% higher onset strain of densification. The bimodal foams have the advantages of a flat deformation regime, high plateau stress and good ductility. They are potentially excellent choice for energy absorption applications.