Fabrication and compression properties of bulk hierarchical nanoporous copper with fine ligament

•Al-Cu alloy were prepared by mechanical alloying and spark plasma sintering.•Bulk hierarchical nanoporous copper (BHNPC) was obtained by chemical dealloying.•BHNPC possess both high porosity and fine ligament size can be obtained.•The bulk nanoporous copper has a compressive strength of 5.8 MPa.

In the present study, Al–Cu alloy with fine grain of ~400 nm has been prepared by mechanical alloying and spark plasma sintering (MA–SPS). Then bulk hierarchical nanoporous copper (BHNPC) was obtained by chemical dealloying of the resultant alloys. Results show that BHNPC possess a highly porosity of ~80% and fine ligament size of about 27 nm that can be prepared without either applied potential or addition of other element such as nickel. Furthermore, compression properties of BHNPC were investigated. The bulk nanoporous copper has a compressive strength of 5.8 MPa. The main failure is brittle fracture, which is probably due to the defects that were generated in the bulk after chemical dealloyed in high concentration alkali solutions.