Strength of Graphene-Coated Ni Bi-Crystals: A Molecular Dynamics Nano-Indentation Study
Nanoindentation simulations are performed for a Ni(111) bi-crystal, in which the grain boundary is coated by a graphene layer. We study both a weak and a strong interface, realized by a <inline-formula> <math display="inline"> <semantics> <msup> <mn>30</mn&...
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| Format: | Article |
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MDPI AG
2020-04-01
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| Series: | Materials |
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| Online Access: | https://www.mdpi.com/1996-1944/13/7/1683 |
| _version_ | 1797571485087301632 |
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| author | Vardan Hoviki Vardanyan Herbert M. Urbassek |
| author_facet | Vardan Hoviki Vardanyan Herbert M. Urbassek |
| author_sort | Vardan Hoviki Vardanyan |
| collection | DOAJ |
| description | Nanoindentation simulations are performed for a Ni(111) bi-crystal, in which the grain boundary is coated by a graphene layer. We study both a weak and a strong interface, realized by a <inline-formula> <math display="inline"> <semantics> <msup> <mn>30</mn> <mo>∘</mo> </msup> </semantics> </math> </inline-formula> and a <inline-formula> <math display="inline"> <semantics> <msup> <mn>60</mn> <mo>∘</mo> </msup> </semantics> </math> </inline-formula> twist boundary, respectively, and compare our results for the composite also with those of an elemental Ni bi-crystal. We find hardening of the elemental Ni when a strong, i.e., low-energy, grain boundary is introduced, and softening for a weak grain boundary. For the strong grain boundary, the interface barrier strength felt by dislocations upon passing the interface is responsible for the hardening; for the weak grain boundary, confinement of the dislocations results in the weakening. For the Ni-graphene composite, we find in all cases a weakening influence that is caused by the graphene blocking the passage of dislocations and absorbing them. In addition, interface failure occurs when the indenter reaches the graphene, again weakening the composite structure. |
| first_indexed | 2024-03-10T20:41:19Z |
| format | Article |
| id | doaj.art-c0f48a6b0cc9481491cdb1b0c30bb250 |
| institution | Directory Open Access Journal |
| issn | 1996-1944 |
| language | English |
| last_indexed | 2024-03-10T20:41:19Z |
| publishDate | 2020-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Materials |
| spelling | doaj.art-c0f48a6b0cc9481491cdb1b0c30bb2502023-11-19T20:41:20ZengMDPI AGMaterials1996-19442020-04-01137168310.3390/ma13071683Strength of Graphene-Coated Ni Bi-Crystals: A Molecular Dynamics Nano-Indentation StudyVardan Hoviki Vardanyan0Herbert M. Urbassek1Physics Department and Research Center OPTIMAS, University Kaiserslautern, Erwin-Schrödinger-Straße, D-67663 Kaiserslautern, GermanyPhysics Department and Research Center OPTIMAS, University Kaiserslautern, Erwin-Schrödinger-Straße, D-67663 Kaiserslautern, GermanyNanoindentation simulations are performed for a Ni(111) bi-crystal, in which the grain boundary is coated by a graphene layer. We study both a weak and a strong interface, realized by a <inline-formula> <math display="inline"> <semantics> <msup> <mn>30</mn> <mo>∘</mo> </msup> </semantics> </math> </inline-formula> and a <inline-formula> <math display="inline"> <semantics> <msup> <mn>60</mn> <mo>∘</mo> </msup> </semantics> </math> </inline-formula> twist boundary, respectively, and compare our results for the composite also with those of an elemental Ni bi-crystal. We find hardening of the elemental Ni when a strong, i.e., low-energy, grain boundary is introduced, and softening for a weak grain boundary. For the strong grain boundary, the interface barrier strength felt by dislocations upon passing the interface is responsible for the hardening; for the weak grain boundary, confinement of the dislocations results in the weakening. For the Ni-graphene composite, we find in all cases a weakening influence that is caused by the graphene blocking the passage of dislocations and absorbing them. In addition, interface failure occurs when the indenter reaches the graphene, again weakening the composite structure.https://www.mdpi.com/1996-1944/13/7/1683molecular dynamicsnickel-graphene compositesdislocation interaction with interfaceinterface failure |
| spellingShingle | Vardan Hoviki Vardanyan Herbert M. Urbassek Strength of Graphene-Coated Ni Bi-Crystals: A Molecular Dynamics Nano-Indentation Study Materials molecular dynamics nickel-graphene composites dislocation interaction with interface interface failure |
| title | Strength of Graphene-Coated Ni Bi-Crystals: A Molecular Dynamics Nano-Indentation Study |
| title_full | Strength of Graphene-Coated Ni Bi-Crystals: A Molecular Dynamics Nano-Indentation Study |
| title_fullStr | Strength of Graphene-Coated Ni Bi-Crystals: A Molecular Dynamics Nano-Indentation Study |
| title_full_unstemmed | Strength of Graphene-Coated Ni Bi-Crystals: A Molecular Dynamics Nano-Indentation Study |
| title_short | Strength of Graphene-Coated Ni Bi-Crystals: A Molecular Dynamics Nano-Indentation Study |
| title_sort | strength of graphene coated ni bi crystals a molecular dynamics nano indentation study |
| topic | molecular dynamics nickel-graphene composites dislocation interaction with interface interface failure |
| url | https://www.mdpi.com/1996-1944/13/7/1683 |
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