Density dependence of the compressive properties of porous copper over a wide density range

The compressive properties of porous copper with relative densities, ρ/ρs, of 0.22–0.96 were investigated. In the low relative density range (ρ/ρs < 0.5–0.6), porous copper showed a density exponent n of 2.3, where n represents the relative density dependence of yield strength. In this range, the bending and buckling of cell walls and the formation of macroscopic deformation bands were observed. However, porous copper with a higher relative density (0.5–0.6 < ρ/ρs < 0.9–1) had an n value of ∼1, where the dominant deformation mode of cell walls was yielding, and no clear deformation band was observed. Also, in the highest relative density range (ρ/ρs very close to 1), the compressive properties degraded markedly with decreasing density, indicating that stress concentration around the minimal pores occurred in this density range.