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Anomalous compliance and early yielding of nanoporous gold

Ngô, Bao-Nam Dinh ; Stukowski, Alexander ; Mameka, Nadiia ; Markmann, Jürgen ; Albe, Karsten ; Weissmüller, Jörg (2015)
Anomalous compliance and early yielding of nanoporous gold.
In: Acta Materialia, 93
doi: 10.1016/j.actamat.2015.04.021
Artikel, Bibliographie

Kurzbeschreibung (Abstract)

We present a study of the elastic and plastic behavior of nanoporous gold in compression, focusing on molecular dynamics simulation and inspecting experimental data for verification. Both approaches agree on an anomalously high elastic compliance in the early stages of deformation, along with a quasi immediate onset of plastic yielding even at the smallest load. Already before the first loading, the material undergoes spontaneous plastic deformation under the action of the capillary forces, requiring no external load. Plastic deformation under compressive load is accompanied by dislocation storage and dislocation interaction, along with strong strain hardening. Dislocation-starvation scenarios are not supported by our results. The stiffness increases during deformation, but never approaches the prediction by the relevant Gibson–Ashby scaling law. Microstructural disorder affects the plastic deformation behavior and surface excess elasticity might modify elastic response, yet we relate the anomalous compliance and the immediate yield onset to an atomistic origin: the large surface-induced prestress induces elastic shear that brings some regions in the material close to the shear instability of the generalized stacking fault energy curve. These regions are elastically highly compliant and plastically weak.

Typ des Eintrags: Artikel
Erschienen: 2015
Autor(en): Ngô, Bao-Nam Dinh ; Stukowski, Alexander ; Mameka, Nadiia ; Markmann, Jürgen ; Albe, Karsten ; Weissmüller, Jörg
Art des Eintrags: Bibliographie
Titel: Anomalous compliance and early yielding of nanoporous gold
Sprache: Englisch
Publikationsjahr: 21 Mai 2015
Verlag: Elsevier
Titel der Zeitschrift, Zeitung oder Schriftenreihe: Acta Materialia
Jahrgang/Volume einer Zeitschrift: 93
DOI: 10.1016/j.actamat.2015.04.021
Kurzbeschreibung (Abstract):

We present a study of the elastic and plastic behavior of nanoporous gold in compression, focusing on molecular dynamics simulation and inspecting experimental data for verification. Both approaches agree on an anomalously high elastic compliance in the early stages of deformation, along with a quasi immediate onset of plastic yielding even at the smallest load. Already before the first loading, the material undergoes spontaneous plastic deformation under the action of the capillary forces, requiring no external load. Plastic deformation under compressive load is accompanied by dislocation storage and dislocation interaction, along with strong strain hardening. Dislocation-starvation scenarios are not supported by our results. The stiffness increases during deformation, but never approaches the prediction by the relevant Gibson–Ashby scaling law. Microstructural disorder affects the plastic deformation behavior and surface excess elasticity might modify elastic response, yet we relate the anomalous compliance and the immediate yield onset to an atomistic origin: the large surface-induced prestress induces elastic shear that brings some regions in the material close to the shear instability of the generalized stacking fault energy curve. These regions are elastically highly compliant and plastically weak.

Freie Schlagworte: Nanoporous; Molecular dynamics; Small-scale plasticity; Elasticity of nanomaterials
Fachbereich(e)/-gebiet(e): 11 Fachbereich Material- und Geowissenschaften
11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft
11 Fachbereich Material- und Geowissenschaften > Materialwissenschaft > Fachgebiet Materialmodellierung
Zentrale Einrichtungen > Hochschulrechenzentrum (HRZ) > Hochleistungsrechner
Zentrale Einrichtungen > Hochschulrechenzentrum (HRZ)
Zentrale Einrichtungen
Hinterlegungsdatum: 21 Mai 2015 11:20
Letzte Änderung: 15 Sep 2016 11:17
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