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dc.contributor.author
Remington, T. P.
dc.contributor.author
Ruestes, Carlos Javier
dc.contributor.author
Bringa, Eduardo Marcial
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Remington, Bruce A.
dc.contributor.author
Lu, C. H.
dc.contributor.author
Kad, B.
dc.contributor.author
Meyers, Marc A.
dc.date.available
2018-01-03T21:24:35Z
dc.date.issued
2014-08
dc.identifier.citation
Meyers, Marc A.; Kad, B.; Lu, C. H.; Remington, Bruce A.; Bringa, Eduardo Marcial; Ruestes, Carlos Javier; et al.; Plastic deformation in nanoindentation of tantalum: A new mechanism for prismatic loop formation; Elsevier; Acta Materialia; 78; 8-2014; 378-393
dc.identifier.issn
1359-6454
dc.identifier.uri
http://hdl.handle.net/11336/32239
dc.description.abstract
The mechanisms of deformation under a nanoindentation in tantalum, chosen as a model body-centered cubic (bcc) metal, are identified and quantified. Molecular dynamics (MD) simulations and indentation experiments are conducted for [1 0 0], [1 1 0] and [1 1 1] normals to surface orientations. The simulated plastic deformation proceeds by the formation of nanotwins, which rapidly evolve into shear dislocation loops. It is shown through a dislocation analysis that an elementary twin (three layers) is energetically favorable for a diameter below ∼7 nm, at which point a shear loop comprising a perfect dislocation is formed. MD simulations show that shear loops expand into the material by the advancement of their edge components. Simultaneously with this advancement, screw components of the loop cross-slip and generate a cylindrical surface. When opposite segments approach, they eventually cancel by virtue of the attraction between them, forming a quasi-circular prismatic loop composed of edge dislocation segments. This “lasso”-like mechanism by which a shear loop transitions to a prismatic loop is identified for both [0 0 1] and [1 1 1] indentations. The prismatic loops advance into the material along 〈1 1 1〉 directions, transporting material away from the nucleation site. Analytical calculations supplement MD and experimental observations, and provide a framework for the improved understanding of the evolution of plastic deformation under a nanoindenter. Dislocation densities under the indenter are estimated experimentally (∼1.2 × 1015 m−2), by MD (∼7 × 1015 m−2) and through an analytical calculation (2.6–19 × 1015 m−2). Considering the assumptions and simplifications, this agreement is considered satisfactory. MD simulations also show expected changes in pile-up symmetry after unloading, compatible with crystal plasticity.
dc.format
application/pdf
dc.language.iso
eng
dc.publisher
Elsevier
dc.rights
info:eu-repo/semantics/openAccess
dc.rights.uri
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
dc.subject
Nanoindentation
dc.subject
Dislocations
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Molecular Dynamics
dc.subject
Shear Loops
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Prismatic Loops
dc.subject.classification
Otras Nanotecnología
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Nanotecnología
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INGENIERÍAS Y TECNOLOGÍAS
dc.title
Plastic deformation in nanoindentation of tantalum: A new mechanism for prismatic loop formation
dc.type
info:eu-repo/semantics/article
dc.type
info:ar-repo/semantics/artículo
dc.type
info:eu-repo/semantics/publishedVersion
dc.date.updated
2018-01-03T19:57:59Z
dc.journal.volume
78
dc.journal.pagination
378-393
dc.journal.pais
Países Bajos
dc.journal.ciudad
Ámsterdam
dc.description.fil
Fil: Remington, T. P.. University of California at San Diego; Estados Unidos
dc.description.fil
Fil: Ruestes, Carlos Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina
dc.description.fil
Fil: Bringa, Eduardo Marcial. Universidad Nacional de Cuyo. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza; Argentina
dc.description.fil
Fil: Remington, Bruce A.. Lawrence Livermore National Laboratory; Estados Unidos
dc.description.fil
Fil: Lu, C. H.. University of California at San Diego; Estados Unidos
dc.description.fil
Fil: Kad, B.. University of California at San Diego; Estados Unidos
dc.description.fil
Fil: Meyers, Marc A.. University of California at San Diego; Estados Unidos
dc.journal.title
Acta Materialia
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/http://www.sciencedirect.com/science/article/pii/S1359645414004881
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1016/j.actamat.2014.06.058
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