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dc.contributor.author
Yang, Wen
dc.contributor.author
Ruestes, Carlos Javier
dc.contributor.author
Li, Zezhou
dc.contributor.author
Abad, Oscar Torrents
dc.contributor.author
Langdon, Terence G.
dc.contributor.author
Heiland, Birgit
dc.contributor.author
Koch, Marcus
dc.contributor.author
Arzt, Eduard
dc.contributor.author
Meyers, Marc A.
dc.date.available
2022-10-18T12:48:13Z
dc.date.issued
2021-05
dc.identifier.citation
Yang, Wen; Ruestes, Carlos Javier; Li, Zezhou; Abad, Oscar Torrents; Langdon, Terence G.; et al.; Micro-mechanical response of ultrafine grain and nanocrystalline tantalum; Elsevier; Journal of Materials Research and Technology; 12; 5-2021; 1804-1815
dc.identifier.issn
2238-7854
dc.identifier.uri
http://hdl.handle.net/11336/173744
dc.description.abstract
In order to investigate the effect of grain boundaries on the mechanical response in the micrometer and submicrometer levels, complementary experiments and molecular dynamics simulations were conducted on a model bcc metal, tantalum. Microscale pillar experiments (diameters of 1 and 2 μm) with a grain size of ~100-200 nm revealed a mechanical response characterized by a yield stress of ~1500 MPa. The hardening of the structure is reflected in the increase in the flow stress to 1700 MPa at a strain of ~0.35. Molecular dynamics simulations were conducted for nanocrystalline tantalum with grain sizes in the range of 20-50 nm and pillar diameters in the same range. The yield stress was approximately 6000 MPa for all specimens and the maximum of the stress-strain curves occurred at a strain of 0.07. Beyond that strain, the material softened because of its inability to store dislocations. The experimental results did not show a significant size dependence of yield stress on pillar diameter (equal to 1 and 2 um), which is attributed to the high ratio between pillar diameter and grain size (~10-20). This behavior is quite different from that in monocrystalline specimens where dislocation 'starvation' leads to a significant size dependence of strength. The ultrafine grains exhibit clear 'pancaking' upon being plastically deformed, with an increase in dislocation density. The plastic deformation is much more localized for the single crystals than for the nanocrystalline specimens, an observation made in both modeling and experiments. In the molecular dynamics simulations, the ratio of pillar diameter (20-50 nm) to grain size was in the range 0.2-2, and a much greater dependence of yield stress to pillar diameter was observed. A critical result from this work is the demonstration that the important parameter in establishing the overall deformation is the ratio between the grain size and pillar diameter; it governs the deformation mode, as well as surface sources and sinks, which are only important when the grain size is of the same order as the pillar diameter.
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-nd/2.5/ar/
dc.subject
MICROPILLAR
dc.subject
NANOCRYSTALLINE
dc.subject
TANTALUM
dc.subject.classification
Ingeniería de los Materiales
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Ingeniería de los Materiales
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INGENIERÍAS Y TECNOLOGÍAS
dc.title
Micro-mechanical response of ultrafine grain and nanocrystalline tantalum
dc.type
info:eu-repo/semantics/article
dc.type
info:ar-repo/semantics/artículo
dc.type
info:eu-repo/semantics/publishedVersion
dc.date.updated
2022-10-13T16:43:09Z
dc.journal.volume
12
dc.journal.pagination
1804-1815
dc.journal.pais
Países Bajos
dc.journal.ciudad
Amsterdam
dc.description.fil
Fil: Yang, Wen. 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. Instituto Interdisciplinario de Ciencias Básicas. - Universidad Nacional de Cuyo. Instituto Interdisciplinario de Ciencias Básicas; Argentina
dc.description.fil
Fil: Li, Zezhou. University of California at San Diego; Estados Unidos
dc.description.fil
Fil: Abad, Oscar Torrents. Leibniz Institute for New Materials; Alemania
dc.description.fil
Fil: Langdon, Terence G.. University of Southern California; Estados Unidos
dc.description.fil
Fil: Heiland, Birgit. Leibniz Institute for New Materials; Alemania
dc.description.fil
Fil: Koch, Marcus. Leibniz Institute for New Materials; Alemania
dc.description.fil
Fil: Arzt, Eduard. Leibniz Institute for New Materials; Alemania. Universitat Saarland; Alemania
dc.description.fil
Fil: Meyers, Marc A.. University of California at San Diego; Estados Unidos
dc.journal.title
Journal of Materials Research and Technology
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/url/https://www.sciencedirect.com/science/article/pii/S2238785421003070
dc.relation.alternativeid
info:eu-repo/semantics/altIdentifier/doi/http://dx.doi.org/10.1016/j.jmrt.2021.03.080
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