A novel approach for in-situ producing Al2O3/aluminum matrix syntactic foam with high specific strength

Low-density foams with high strength are eagerly desired to use as energy absorption and shock isolation systems during transportation. In this work, an Al2O3/aluminum matrix syntactic foam with a density of 1.41 g/cm3 and a compressive strength of 238 MPa was prepared by a novel approach, which specific strength outperforms the most advanced aluminum matrix syntactic foams as reported in the literature. Especially, the hollow Al2O3 spheres were produced by an in-situ reaction of the hollow glass beads in this foam. Moreover, an electric current was first utilized in this new approach, which proved to have a crucial effect on the in-situ reaction, making the hollow glass beads rapidly and completely transform into Al2O3 spheres to improve interface conditions. The approach is believed to provide a favorable strategy to design different metal matrix syntactic foams with improved performance.