  Structure is the most distinctive feature of nanoporous metals. The intricate
maze of rounded shapes, where ligaments and pores run after each other
disorderly, strikes imagination no less than it imparts properties that, tuned
by size effects, have no counterpart in the bulk form. Indisputably, nanoporous
Au has been the absolute protagonist of the field of study, unveiling the
disrupting potential of nanoporous metals in areas ranging from catalysis to
energy and sensing. Here, we still focus on nanoporous Au, addressing the
long-standing issue of mechanical properties in nanoporous metals. In
particular, we investigate how Young's modulus changes with ligament size,
being the porosity the same. Based on atomistic replicas generated starting
from experimental tomographic evidence, atomistic simulations reveal that
nanoporous Au stiffens as ligaments become finer, reproducing experimental
findings obtained by nanoindentation of dealloyed samples. Ruled out surface
stress effects, theoretical considerations relate stiffening to the dislocation
density increase.
