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Understanding the rheology of nanocontacts

Mechanical stiffness, as opposed to softness, is a fundamental property of solids. Its persistence or rheological evolution in vibrating solid-solid nanocontacts is important in physics, materials science and technology. A puzzling apparent liquefaction under oscillatory strain, totally unexpected a...

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Autores principales: Khosravi, Ali, Lainé, Antoine, Vanossi, Andrea, Wang, Jin, Siria, Alessandro, Tosatti, Erio
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9068906/
https://www.ncbi.nlm.nih.gov/pubmed/35508482
http://dx.doi.org/10.1038/s41467-022-30096-y
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author Khosravi, Ali
Lainé, Antoine
Vanossi, Andrea
Wang, Jin
Siria, Alessandro
Tosatti, Erio
author_facet Khosravi, Ali
Lainé, Antoine
Vanossi, Andrea
Wang, Jin
Siria, Alessandro
Tosatti, Erio
author_sort Khosravi, Ali
collection PubMed
description Mechanical stiffness, as opposed to softness, is a fundamental property of solids. Its persistence or rheological evolution in vibrating solid-solid nanocontacts is important in physics, materials science and technology. A puzzling apparent liquefaction under oscillatory strain, totally unexpected at room temperature, was suggested by recent experiments on solid gold nano-junctions. Here we show theoretically that realistically simulated nanocontacts actually remain crystalline even under large oscillatory strains. Tensile and compressive slips, respectively of “necking” and “bellying” types, do take place, but recover reversibly even during fast oscillatory cycles. We also show that, counterintuitively, the residual stress remains tensile after both slips, driving the averaged stiffness from positive to negative, thus superficially mimicking a liquid’s. Unlike a liquid, however, rheological softening occurs by stick-slip, predicting largely frequency independent stiffness with violent noise in stress and conductance, properties compatible with experiments. The baffling large amplitude rheology of gold nanocontacts and its consequences should apply, with different parameters, to many other metals.
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spelling pubmed-90689062022-05-05 Understanding the rheology of nanocontacts Khosravi, Ali Lainé, Antoine Vanossi, Andrea Wang, Jin Siria, Alessandro Tosatti, Erio Nat Commun Article Mechanical stiffness, as opposed to softness, is a fundamental property of solids. Its persistence or rheological evolution in vibrating solid-solid nanocontacts is important in physics, materials science and technology. A puzzling apparent liquefaction under oscillatory strain, totally unexpected at room temperature, was suggested by recent experiments on solid gold nano-junctions. Here we show theoretically that realistically simulated nanocontacts actually remain crystalline even under large oscillatory strains. Tensile and compressive slips, respectively of “necking” and “bellying” types, do take place, but recover reversibly even during fast oscillatory cycles. We also show that, counterintuitively, the residual stress remains tensile after both slips, driving the averaged stiffness from positive to negative, thus superficially mimicking a liquid’s. Unlike a liquid, however, rheological softening occurs by stick-slip, predicting largely frequency independent stiffness with violent noise in stress and conductance, properties compatible with experiments. The baffling large amplitude rheology of gold nanocontacts and its consequences should apply, with different parameters, to many other metals. Nature Publishing Group UK 2022-05-04 /pmc/articles/PMC9068906/ /pubmed/35508482 http://dx.doi.org/10.1038/s41467-022-30096-y Text en © The Author(s) 2022 https://creativecommons.org/licenses/by/4.0/Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Article
Khosravi, Ali
Lainé, Antoine
Vanossi, Andrea
Wang, Jin
Siria, Alessandro
Tosatti, Erio
Understanding the rheology of nanocontacts
title Understanding the rheology of nanocontacts
title_full Understanding the rheology of nanocontacts
title_fullStr Understanding the rheology of nanocontacts
title_full_unstemmed Understanding the rheology of nanocontacts
title_short Understanding the rheology of nanocontacts
title_sort understanding the rheology of nanocontacts
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9068906/
https://www.ncbi.nlm.nih.gov/pubmed/35508482
http://dx.doi.org/10.1038/s41467-022-30096-y
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