Cell Wall Buckling Mediated Energy Absorption in Lotus-type Porous Copper

The energy absorption characteristics of the lotus-type porous coppers at the strain rate of 10-3 s-1 to ~2400 s-1 were systematically investigated. Depending on the relative density and loading rate, the energy absorption capability of the tested samples varied from ~20 to ~85 MJ m-3, while the energy absorption efficiency fluctuated around ~0.6. An energy absorption efficiency curve based approach was proposed for unambiguous identification of the plateau regime, which gave an extension of ~0.50 strain range for the presently investigated porous coppers. With detailed observations of cell wall morphologies at various deformation stages, it was suggested that buckling of cell walls was the dominant mechanism mediating the energy absorption in lotus-type porous coppers.