We studied the elastic constants of a lotus-type porous copper, regarding it as a composite material showing hexagonal elastic symmetry with the c-axis along the longitudinal direction of the pores. We used the combination of resonance ultrasound spectroscopy and electromagnetic acoustic resonance methods to determine the elastic constants of the composite. The resulting Young's modulus E∥ decreases linearly and c33 does slowly with porosity, while E⊥ and c11 drop rapidly and then slowly. Micromechanics calculations considering the elastic anisotropy of the copper matrix can reproduce the measured anisotropic elastic constants. This indicates that the elastic properties of various types of porous metals can be predicted and designed with the present approach using micromechanics modeling.
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