期刊
ACTA MATERIALIA
卷 61, 期 9, 页码 3249-3256出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.actamat.2013.02.013
关键词
Nanoporous; Mechanical properties; Molecular dynamics
资金
- NSF IRD program
- Argentinean Science Agency [PICT2009-0092]
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, similar to 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. (C) 2013 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.
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