Surface stresses and Young’s modulus in nanoporous Au foams

A theoretical model is developed to relate structure and mechanical properties in nanoporous metals. It is shown that undercoordinated surface atoms generate surface stresses that enhance the Young’s modulus of individual ligaments and of the nanoporous metal. The model perfectly reproduces the experimental Young’s modulus of nanoporous Au if ligaments are allowed to bend over an effective length shorter than the nominal one. The effective bending length is roughly 2/3 the nominal one over two orders of magnitude.