Coarsening of nanoporous Au: Relationship between structure and mechanical properties

Chemical dealloying was used to fabricate nanoporous Au samples with fine ligaments. The samples were subjected to isothermal annealing at relatively low temperature to induce slow, limited coarsening. This allowed obtaining a sequence of progressively coarsened nanoporous Au samples with correlated structure. Scanning and transmission electron microscopies were utilized to measure the characteristic lengths of nanoporous Au and investigate accurately its coarsening kinetics. Nanoindentation experiments were also performed to estimate Young’s modulus and yield strength. It is shown that mechanical properties undergo a gradual variation related to structural evolution. The observed mechanical behavior is tentatively rationalized by a simplified model able to describe the mechanical response of nanoporous metal structures with thick ligaments and massive nodes.