Reducing deformation anisotropy to achieve ultrahigh strength and ductility in Mg at the nanoscale
In mechanical deformation of crystalline materials, the critical resolved shear stress (CRSS; τ[subscript CRSS]) is the stress required to initiate movement of dislocations on a specific plane. In plastically anisotropic materials, such as Mg, τ[subscript CRSS] for different slip systems differs gre...
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| Format: | Article |
| Language: | en_US |
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National Academy of Sciences (U.S.)
2014
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| Online Access: | http://hdl.handle.net/1721.1/85911 https://orcid.org/0000-0002-0201-9333 https://orcid.org/0000-0002-7841-8058 |
| _version_ | 1811097045894692864 |
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| author | Qi, Liang Li, Ju Yu, Qian Mishra, Raja K. Minor, Andrew M. |
| author2 | Massachusetts Institute of Technology. Department of Materials Science and Engineering |
| author_facet | Massachusetts Institute of Technology. Department of Materials Science and Engineering Qi, Liang Li, Ju Yu, Qian Mishra, Raja K. Minor, Andrew M. |
| author_sort | Qi, Liang |
| collection | MIT |
| description | In mechanical deformation of crystalline materials, the critical resolved shear stress (CRSS; τ[subscript CRSS]) is the stress required to initiate movement of dislocations on a specific plane. In plastically anisotropic materials, such as Mg, τ[subscript CRSS] for different slip systems differs greatly, leading to relatively poor ductility and formability. However, τ[subscript CRSS] for all slip systems increases as the physical dimension of the sample decreases to approach eventually the ideal shear stresses of a material, which are much less anisotropic. Therefore, as the size of a sample gets smaller, the yield stress increases and τ[subscript CRSS] anisotropy decreases. Here, we use in situ transmission electron microscopy mechanical testing and atomistic simulations to demonstrate that τ[subscript CRSS] anisotropy can be significantly reduced in nanoscale Mg single crystals, where extremely high stresses (~2 GPa) activate multiple deformation modes, resulting in a change from basal slip-dominated plasticity to a more homogeneous plasticity. Consequently, an abrupt and dramatic size-induced “brittle-to-ductile” transition occurs around 100 nm. This nanoscale change in the CRSS anisotropy demonstrates the powerful effect of size-related deformation mechanisms and should be a general feature in plastically anisotropic materials. |
| first_indexed | 2024-09-23T16:53:28Z |
| format | Article |
| id | mit-1721.1/85911 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T16:53:28Z |
| publishDate | 2014 |
| publisher | National Academy of Sciences (U.S.) |
| record_format | dspace |
| spelling | mit-1721.1/859112022-10-03T08:56:49Z Reducing deformation anisotropy to achieve ultrahigh strength and ductility in Mg at the nanoscale Qi, Liang Li, Ju Yu, Qian Mishra, Raja K. Minor, Andrew M. Massachusetts Institute of Technology. Department of Materials Science and Engineering Massachusetts Institute of Technology. Department of Nuclear Science and Engineering Qi, Liang Li, Ju In mechanical deformation of crystalline materials, the critical resolved shear stress (CRSS; τ[subscript CRSS]) is the stress required to initiate movement of dislocations on a specific plane. In plastically anisotropic materials, such as Mg, τ[subscript CRSS] for different slip systems differs greatly, leading to relatively poor ductility and formability. However, τ[subscript CRSS] for all slip systems increases as the physical dimension of the sample decreases to approach eventually the ideal shear stresses of a material, which are much less anisotropic. Therefore, as the size of a sample gets smaller, the yield stress increases and τ[subscript CRSS] anisotropy decreases. Here, we use in situ transmission electron microscopy mechanical testing and atomistic simulations to demonstrate that τ[subscript CRSS] anisotropy can be significantly reduced in nanoscale Mg single crystals, where extremely high stresses (~2 GPa) activate multiple deformation modes, resulting in a change from basal slip-dominated plasticity to a more homogeneous plasticity. Consequently, an abrupt and dramatic size-induced “brittle-to-ductile” transition occurs around 100 nm. This nanoscale change in the CRSS anisotropy demonstrates the powerful effect of size-related deformation mechanisms and should be a general feature in plastically anisotropic materials. National Science Foundation (U.S.) (Grant DMR-1120901) National Science Foundation (U.S.) (Grant DMR-1008104) General Motors Research and Development Center 2014-03-24T18:10:06Z 2014-03-24T18:10:06Z 2013-08 2013-04 Article http://purl.org/eprint/type/JournalArticle 0027-8424 1091-6490 http://hdl.handle.net/1721.1/85911 Yu, Q., L. Qi, R. K. Mishra, J. Li, and A. M. Minor. “Reducing Deformation Anisotropy to Achieve Ultrahigh Strength and Ductility in Mg at the Nanoscale.” Proceedings of the National Academy of Sciences 110, no. 33 (August 13, 2013): 13289–13293. https://orcid.org/0000-0002-0201-9333 https://orcid.org/0000-0002-7841-8058 en_US http://dx.doi.org/10.1073/pnas.1306371110 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 National Academy of Sciences (U.S.) National Academy of Science (U.S.) |
| spellingShingle | Qi, Liang Li, Ju Yu, Qian Mishra, Raja K. Minor, Andrew M. Reducing deformation anisotropy to achieve ultrahigh strength and ductility in Mg at the nanoscale |
| title | Reducing deformation anisotropy to achieve ultrahigh strength and ductility in Mg at the nanoscale |
| title_full | Reducing deformation anisotropy to achieve ultrahigh strength and ductility in Mg at the nanoscale |
| title_fullStr | Reducing deformation anisotropy to achieve ultrahigh strength and ductility in Mg at the nanoscale |
| title_full_unstemmed | Reducing deformation anisotropy to achieve ultrahigh strength and ductility in Mg at the nanoscale |
| title_short | Reducing deformation anisotropy to achieve ultrahigh strength and ductility in Mg at the nanoscale |
| title_sort | reducing deformation anisotropy to achieve ultrahigh strength and ductility in mg at the nanoscale |
| url | http://hdl.handle.net/1721.1/85911 https://orcid.org/0000-0002-0201-9333 https://orcid.org/0000-0002-7841-8058 |
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