Understanding the mechanisms of amorphous creep through molecular simulation
Molecular processes of creep in metallic glass thin films are simulated at experimental timescales using a metadynamics-based atomistic method. Space-time evolutions of the atomic strains and nonaffine atom displacements are analyzed to reveal details of the atomic-level deformation and flow process...
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| Format: | Article |
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Proceedings of the National Academy of Sciences
2018
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| Online Access: | http://hdl.handle.net/1721.1/116602 https://orcid.org/0000-0002-9216-2482 https://orcid.org/0000-0002-2727-0137 |
| _version_ | 1810990124112019456 |
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| author | Cao, Penghui Short, Michael P Yip, Sidney |
| author2 | Massachusetts Institute of Technology. Department of Materials Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Materials Science and Engineering Cao, Penghui Short, Michael P Yip, Sidney |
| author_sort | Cao, Penghui |
| collection | MIT |
| description | Molecular processes of creep in metallic glass thin films are simulated at experimental timescales using a metadynamics-based atomistic method. Space-time evolutions of the atomic strains and nonaffine atom displacements are analyzed to reveal details of the atomic-level deformation and flow processes of amorphous creep in response to stress and thermal activations. From the simulation results, resolved spatially on the nanoscale and temporally over time increments of fractions of a second, we derive a mechanistic explanation of the well-known variation of creep rate with stress. We also construct a deformation map delineating the predominant regimes of diffusional creep at low stress and high temperature and deformational creep at high stress. Our findings validate the relevance of two original models of the mechanisms of amorphous plasticity: one focusing on atomic diffusion via free volume and the other focusing on stress-induced shear deformation. These processes are found to be nonlinearly coupled through dynamically heterogeneous fluctuations that characterize the slow dynamics of systems out of equilibrium. Keywords: creep, molecular simulation, deformation mechanism, atomistic modeling, metallic glass |
| first_indexed | 2024-09-23T12:32:48Z |
| format | Article |
| id | mit-1721.1/116602 |
| institution | Massachusetts Institute of Technology |
| last_indexed | 2024-09-23T12:32:48Z |
| publishDate | 2018 |
| publisher | Proceedings of the National Academy of Sciences |
| record_format | dspace |
| spelling | mit-1721.1/1166022022-09-28T08:30:30Z Understanding the mechanisms of amorphous creep through molecular simulation Cao, Penghui Short, Michael P Yip, Sidney Massachusetts Institute of Technology. Department of Materials Science and Engineering Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Cao, Penghui Short, Michael P Yip, Sidney Molecular processes of creep in metallic glass thin films are simulated at experimental timescales using a metadynamics-based atomistic method. Space-time evolutions of the atomic strains and nonaffine atom displacements are analyzed to reveal details of the atomic-level deformation and flow processes of amorphous creep in response to stress and thermal activations. From the simulation results, resolved spatially on the nanoscale and temporally over time increments of fractions of a second, we derive a mechanistic explanation of the well-known variation of creep rate with stress. We also construct a deformation map delineating the predominant regimes of diffusional creep at low stress and high temperature and deformational creep at high stress. Our findings validate the relevance of two original models of the mechanisms of amorphous plasticity: one focusing on atomic diffusion via free volume and the other focusing on stress-induced shear deformation. These processes are found to be nonlinearly coupled through dynamically heterogeneous fluctuations that characterize the slow dynamics of systems out of equilibrium. Keywords: creep, molecular simulation, deformation mechanism, atomistic modeling, metallic glass United States. Department of Energy (Grant DE-NE0008450) National Science Foundation (U.S.) (CAREER Grant DMR-1654548) United States. Department of Energy. Office of Basic Energy Sciences (Grant DE-SC0002633) 2018-06-26T13:47:36Z 2018-06-26T13:47:36Z 2017-12 2018-06-21T15:45:53Z Article http://purl.org/eprint/type/JournalArticle 0027-8424 1091-6490 http://hdl.handle.net/1721.1/116602 Cao, Penghui, et al. “Understanding the Mechanisms of Amorphous Creep through Molecular Simulation.” Proceedings of the National Academy of Sciences, vol. 114, no. 52, Dec. 2017, pp. 13631–36. https://orcid.org/0000-0002-9216-2482 https://orcid.org/0000-0002-2727-0137 http://dx.doi.org/10.1073/PNAS.1708618114 Proceedings of the National Academy of Sciences Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Proceedings of the National Academy of Sciences PNAS |
| spellingShingle | Cao, Penghui Short, Michael P Yip, Sidney Understanding the mechanisms of amorphous creep through molecular simulation |
| title | Understanding the mechanisms of amorphous creep through molecular simulation |
| title_full | Understanding the mechanisms of amorphous creep through molecular simulation |
| title_fullStr | Understanding the mechanisms of amorphous creep through molecular simulation |
| title_full_unstemmed | Understanding the mechanisms of amorphous creep through molecular simulation |
| title_short | Understanding the mechanisms of amorphous creep through molecular simulation |
| title_sort | understanding the mechanisms of amorphous creep through molecular simulation |
| url | http://hdl.handle.net/1721.1/116602 https://orcid.org/0000-0002-9216-2482 https://orcid.org/0000-0002-2727-0137 |
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