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Ling-Zhi Liu1 Hai-Jun Jin1

1, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, , China

As a three dimensional network of nanoscale Au struts (or ligaments), the nanoporous gold (NPG) often combines some properties of the porous materials and that of the nanoscale crystals. But one property, i.e., the plateau plastic yielding in compression, which is often observed in both porous materials and the nanoscale solids, has yet been conclusively achieved in nanoporous metals. Some small scale testing and simulation studies showed that the plateau plastic yielding may exist in compression of NPG. However, as far as the authors know, all macroscopic scale mechanical tests of previous NPG samples revealed an apparent "strain hardening" after yielding during compression, irrespective of the structure size and the relative density. The lack of the plateau plastic yielding and the presence of “strain hardening” in compression of NPG may be attributed to the densification of porous structure and thus the increase in network connectivity during compression, and/or arguably the strain hardening in the (bended) individual nano-ligaments. Here we report that by properly modifying the structure of a dealloying-made NPG, the plateau plastic yielding can appear in the compression stress-strain curve of the macroscopic NPG samples. A comparative study between the NPG samples with and without the plateau plastic yielding, with respect to their structure and deformation mechanisms, will be presented.

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