Effect of spherical and cubical space holders on the microstructural characteristics and its consequences on mechanical and thermal properties of open-cell aluminum foam

The effect of relative density (RD) and shape of the space holder on microstructural characteristics and compressive behavior of open-cell aluminum foams (OAFs) have been studied. OAFs with tailored porous morphologies (50–81%) were successfully prepared through space holder technique using spherical shape carbamide and cubic shape sucrose space holders in various amounts. Al powder and space holders were mixed with 2 wt% of polyvinyl alcohol (PVA) binder solution, compacted at 300 MPa and finally sintered at 650 °C for 3 h. It was observed that the microstructural characteristics of OAFs varied in accordance with the shapes of space holders. The results reveal that the OAFs prepared with carbamide show smooth microstructure, higher plateau stress (~3 times), higher energy absorption (~3 times) and higher Young's modulus, but lower densification strain, compared to the OAFs prepared with sucrose. The Young's modulus, plateau stress, and energy absorption of OAFs, follow the power-law relationship as a function of its RD irrespective of the shape of space holders. The thermal conductivity of Al-carb and Al-suc OAFs are noted to be not much in variation irrespective of the shape of the pores.