Preparation and Compression Behavior of Multiscale Hierarchical Porous Copper with High Porosity

In this study, multiscale hierarchical porous copper with micron‐to‐nanometer structure is synthesized using chemical dealloying in conjunction with space holders NaCl and KCl. Two groups of two‐level hierarchical structures and three groups of three‐level hierarchical structures are created by varying the micron‐scale pore dimensions and volume ratio while preserving the theoretical porosity (84%) and nanoscale porous structure. Reduction of micron‐scale pore dimensions in the two‐level hierarchical structures from 150 to 30 μm yields a fold enhancement in compressive strength and a 2.49‐fold improvement in energy absorption capacity. The creation of the three‐level hierarchical structure enhances the compression performance even further, resulting in optimal mechanical properties at a 1:2 ratio of 150–30 μm pore volume. This structure demonstrates a 1.56‐fold increase in compressive strength while maintaining comparable or superior energy absorption value and efficiency when compared to the two‐level hierarchical structure with 30 μm‐scale pores.