Microstructural Characterization and Deformation Behavior of Zn–8Al-Cenosphere Hybrid Foam

Abstract

Zn–8Al alloy with density 6.3 g/cm3 was foamed by using cenosphere particles as a thickening agent and CaH2 as foaming agent via stir-casting technique. The cenosphere particles also worked as a space holder to create microporosity into the foam structure. The relative density of the hybrid foam has been obtained in the range of 0.18–0.27. The synthesized hybrid foam was studied under microscopic evaluation and compressive deformation behavior. From scanning electron microscopic observation, it was found that cenosphere particles are dispersed into the cell walls of the hybrid foam as the strengthening material. Compressive deformation of the samples sliced from the foam ingot was examined with different conditions to find out the effect of strain rate and temperature. The properties were evaluated in terms of plateau stress, energy absorption capacity, densification strain, maximum stress and energy absorption efficiency. The present work is focused on the parameters which affect energy absorption efficiency of hybrid foam. It was noted that plateau stress and energy absorption capacity increases with relative density and strain rate. The temperature of the furnace during the compression test was varied from 100 to 250 °C and the result obtained shows that plateau stress and energy absorption capacity values reduces with an increase in temperature during the compression test. The energy absorption efficiency of the hybrid foam varies in the range of 56–90% as it depends on the compressive deformation. More constant plateau region results in higher energy absorption efficiency. Densification strain is found to be almost constant for each set of conditions.