We synthesize nanoporous copper (NP Cu) through electrochemical dealloying of amorphous Cu0.41Si0.59 under compressive residual stress. Transmission Electron Microscopy reveals that struts are nanocrystalline with grain size equal to the strut thickness. Moreover, a significant population of twins with spacing ∼7 nm is present within each imaged grain. The hardness of this nanocrystalline, nanotwinned NP Cu is approximately one order of magnitude greater than reports on NP Cu in the literature. The yield strength of individual struts inferred through dimensional analysis is approximately an order of magnitude greater than bulk copper and compares well with other nanostructured copper systems.
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We are grateful to NSF for support through Grant Nos. CMMI-1200857 and CMMI-1301268. This work was performed, in part, at the Center for Integrated Nanotechnologies, an Office of Science User Facility operated for the U.S. Department of Energy (DOE) Office of Science. Los Alamos National Laboratory, an affirmative action equal opportunity employer, is operated by Los Alamos National Security, LLC, for the National Nuclear Security Administration of the U.S. Department of Energy under Contract DE-AC52-06NA25396. Contributions from M.K. were supported by NSF through RET Program No. DMR-0851574.