Mechanical response of nanoporous gold

• Autores: Farkas, Diana; Caro, Alfredo; Bringa, Eduardo Marcial; Crowson, Douglas
• Año de publicación: 2013
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Nanoporous; Mechanical Properties; Molecular Dynamics
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

We report the results of computational tensile and compressive tests for model bi-continuous nanoporous gold structures using atomistic simulations with empirical many-body potentials and molecular dynamics. The results are compared with the predictions of scaling laws for coarser-scale foams and with available experimental data. We find a surprising substantial tension/compression asymmetry in yield due to the surface stress that sets the filament under compression, providing a bias favoring yielding in compression. We provide a model for our results based on a ligament strength value close to the theoretical strength of Au, and the surface stress. The model predicts a significant tension/compression asymmetry for ligament sizes below ∼10 nm and pore collapse for ligament sizes below 1 nm. We also observe an unexpected compaction tendency under tension characterized by a decrease in the total volume of the sample of 15% for samples deformed under tension by 30%. The mechanism of the compaction involves a decrease in the average pore size and pore collapse resulting from plasticity within the ligaments.
Fil: Farkas, Diana. Virginia Polytechnic Institute; Estados Unidos;
Fil: Caro, Alfredo. Material Science and Technology Division, Los Alamos National Laboratory; Estados Unidos;
Fil: Bringa, Eduardo Marcial. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Mendoza; Argentina;
Fil: Crowson, Douglas. Virginia Polytechnic Institute; Estados Unidos;