Strength of open-cell 6101 aluminum foams under free and constrained compression

Mechanical properties of open-cell 6101 aluminum alloy foams with three different pore sizes under free and constrained compression were studied at two different strain rates. It was found that the interaction between the foam and the bore provides local reinforcement against deformation of the cell walls leading to a small increase in the modulus and densification strain during constrained deformation. Compressive mechanical properties of the foam exhibited little strain rate sensitivity during free and constrained deformation. It is thought that there could be some change in the deformation mechanism of these foams at strain rates higher than usual quasi-static strain rates. To understand how different microstructures can affect properties of these foams, structures were heat treated at 175 °C and 600 °C for 50 h. Mechanical properties of low temperature heat treated foams were found to govern by inherent matrix strength while the second phases and grain boundary cracks affected properties of foams heat treated at higher temperatures.