Stiffening of nanoporous gold: experiment, simulation and theory
Dipartimento di Fisica, Università degli Studi di Cagliari, Cittadella Universitaria, 09042, Monserrato, CA, Italy
2 Dipartimento di Ingegneria Meccanica, Chimica, e dei Materiali, Università degli Studi di Cagliari, via Marengo 2, 09123, Cagliari, Italy
3 NABLA Lab, Biological and Environmental Sciences and Engineering (BESE) Division, King Abdullah University of Science and Technology (KAUST), 610101, Thuwal, Saudi Arabia
4 Dipartimento di Fisica “Aldo Pontremoli”, Università degli Studi di Milano, Via Celoria 16, 20133, Milan, Italy
5 Univ. Lille, CNRS, Centrale Lille, Univ. Polytechnique Hauts-de-France, UMR 8520,- IEMN - Institut d’Electronique de Microélectronique et de Nanotechnologie, 59000, Lille, France
Accepted: 5 July 2022
Published online: 25 July 2022
By combining electron microscopy measurements, atomistic simulations and elastic homogenization theory, we theoretically investigate the Young’s modulus of nanoporous Au structures. 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. We argue that such a stiffening is neither due to surface stress nor to grain boundaries. Instead, we observe a direct quantitative correlation between the density of dislocations found in the material phase of the nanoporous structures and their Young’s modulus and we propose a microscopic explanation of the observed stiffening. In particular, we show that local stress and strain fields in the neighborhood of dislocation cores allow dislocations to work as reinforcing solutes.
© The Author(s) 2022
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