Microstructural and mechanical properties of Al-SiO2 nanocomposite foams produced by an ultrasonic technique

In this study, nanocomposite foams reinforced with different weight percentages of silicon dioxide nanoparticles (0.25, 0.5, 0.75 and 1.0 wt%) were fabricated using the ultrasonic and stir casting techniques. For this purpose heat treated TiH2 was used as foaming agent. Microstructural studies were done by optical microscope and scanning electron microscope. Hardness evaluation of precursor nanocomposites showed that the hardness was significantly increased by the addition of SiO2 nanoparticles and Al-0.75 wt% SiO2 nanocomposite makes the highest hardness. Evaluation of compressive behavior of Al-SiO2 nanocomposite foams showed that the plateau stress increases more than 3 times as the foam relative density increases from 0.09 to 0.16. Energy absorption of Al-SiO2 nanocomposite foams has been found to be dependent on both relative density and structural properties.