Mechanical properties of ceria nanorods and nanochains; The effect of dislocations, grain-boundaries and oriented attachment

Thi X.T. Sayle, Beverley J. Inkson, Ajay Karakoti, Amit Kumar, Marco Molinari, Günter Möbus, Stephen C. Parker, Sudipta Seal, Dean C. Sayle

Research output: Contribution to journalArticle

29 Citations (Scopus)

Abstract

We predict that the presence of extended defects can reduce the mechanical strength of a ceria nanorod by 70%. Conversely, the pristine material can deform near its theoretical strength limit. Specifically, atomistic models of ceria nanorods have been generated with full microstructure, including: growth direction, morphology, surface roughening (steps, edges, corners), point defects, dislocations and grain-boundaries. The models were then used to calculate the mechanical strength as a function of microstructure. Our simulations reveal that the compressive yield strengths of ceria nanorods, ca. 10 nm in diameter and without extended defects, are 46 and 36 GPa for rods oriented along [211] and [110] respectively, which represents almost 10% of the bulk elastic modulus and are associated with yield strains of about 0.09. Tensile yield strengths were calculated to be about 50% lower with associated yield strains of about 0.06. For both nanorods, plastic deformation was found to proceed via slip in the {001} plane with direction 〈110〉 - a primary slip system for crystals with the fluorite structure. Dislocation evolution for the nanorod oriented along [110] was nucleated via a cerium vacancy present at the surface. A nanorod oriented along [321] and comprising twin-grain boundaries with {111} interfacial planes was calculated to have a yield strength of about 10 GPa (compression and tension) with the grain boundary providing the vehicle for plastic deformation, which slipped in the plane of the grain boundary, with an associated 〈110〉 slip direction. We also predict, using a combination of atomistic simulation and DFT, that rutile-structured ceria is feasible when the crystal is placed under tension. The mechanical properties of nanochains, comprising individual ceria nanoparticles with oriented attachment and generated using simulated self-assembly, were found to be similar to those of the nanorod with grain-boundary. Images of the atom positions during tension and compression are shown, together with animations, revealing the mechanisms underpinning plastic deformation. For the nanochain, our simulations help further our understanding of how a crystallising ice front can be used to 'sculpt' ceria nanoparticles into nanorods via oriented attachment.

Original languageEnglish
Pages (from-to)1823-1837
Number of pages15
JournalNanoscale
Volume3
Issue number4
DOIs
Publication statusPublished - 1 Apr 2011
Externally publishedYes

Fingerprint

Cerium compounds
Nanorods
Dislocations (crystals)
Grain boundaries
Mechanical properties
Yield stress
Plastic deformation
Strength of materials
Nanoparticles
Cerium
Defects
Crystals
Microstructure
Fluorspar
Ice
Point defects
Animation
Discrete Fourier transforms
Self assembly
Vacancies

Cite this

Sayle, Thi X.T. ; Inkson, Beverley J. ; Karakoti, Ajay ; Kumar, Amit ; Molinari, Marco ; Möbus, Günter ; Parker, Stephen C. ; Seal, Sudipta ; Sayle, Dean C. / Mechanical properties of ceria nanorods and nanochains; The effect of dislocations, grain-boundaries and oriented attachment. In: Nanoscale. 2011 ; Vol. 3, No. 4. pp. 1823-1837.
@article{730f772e14a947ea94df370d1cae690e,
title = "Mechanical properties of ceria nanorods and nanochains; The effect of dislocations, grain-boundaries and oriented attachment",
abstract = "We predict that the presence of extended defects can reduce the mechanical strength of a ceria nanorod by 70{\%}. Conversely, the pristine material can deform near its theoretical strength limit. Specifically, atomistic models of ceria nanorods have been generated with full microstructure, including: growth direction, morphology, surface roughening (steps, edges, corners), point defects, dislocations and grain-boundaries. The models were then used to calculate the mechanical strength as a function of microstructure. Our simulations reveal that the compressive yield strengths of ceria nanorods, ca. 10 nm in diameter and without extended defects, are 46 and 36 GPa for rods oriented along [211] and [110] respectively, which represents almost 10{\%} of the bulk elastic modulus and are associated with yield strains of about 0.09. Tensile yield strengths were calculated to be about 50{\%} lower with associated yield strains of about 0.06. For both nanorods, plastic deformation was found to proceed via slip in the {001} plane with direction 〈110〉 - a primary slip system for crystals with the fluorite structure. Dislocation evolution for the nanorod oriented along [110] was nucleated via a cerium vacancy present at the surface. A nanorod oriented along [321] and comprising twin-grain boundaries with {111} interfacial planes was calculated to have a yield strength of about 10 GPa (compression and tension) with the grain boundary providing the vehicle for plastic deformation, which slipped in the plane of the grain boundary, with an associated 〈110〉 slip direction. We also predict, using a combination of atomistic simulation and DFT, that rutile-structured ceria is feasible when the crystal is placed under tension. The mechanical properties of nanochains, comprising individual ceria nanoparticles with oriented attachment and generated using simulated self-assembly, were found to be similar to those of the nanorod with grain-boundary. Images of the atom positions during tension and compression are shown, together with animations, revealing the mechanisms underpinning plastic deformation. For the nanochain, our simulations help further our understanding of how a crystallising ice front can be used to 'sculpt' ceria nanoparticles into nanorods via oriented attachment.",
author = "Sayle, {Thi X.T.} and Inkson, {Beverley J.} and Ajay Karakoti and Amit Kumar and Marco Molinari and G{\"u}nter M{\"o}bus and Parker, {Stephen C.} and Sudipta Seal and Sayle, {Dean C.}",
year = "2011",
month = "4",
day = "1",
doi = "10.1039/c0nr00980f",
language = "English",
volume = "3",
pages = "1823--1837",
journal = "Nanoscale",
issn = "2040-3364",
publisher = "Royal Society of Chemistry",
number = "4",

}

Sayle, TXT, Inkson, BJ, Karakoti, A, Kumar, A, Molinari, M, Möbus, G, Parker, SC, Seal, S & Sayle, DC 2011, 'Mechanical properties of ceria nanorods and nanochains; The effect of dislocations, grain-boundaries and oriented attachment', Nanoscale, vol. 3, no. 4, pp. 1823-1837. https://doi.org/10.1039/c0nr00980f

Mechanical properties of ceria nanorods and nanochains; The effect of dislocations, grain-boundaries and oriented attachment. / Sayle, Thi X.T.; Inkson, Beverley J.; Karakoti, Ajay; Kumar, Amit; Molinari, Marco; Möbus, Günter; Parker, Stephen C.; Seal, Sudipta; Sayle, Dean C.

In: Nanoscale, Vol. 3, No. 4, 01.04.2011, p. 1823-1837.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Mechanical properties of ceria nanorods and nanochains; The effect of dislocations, grain-boundaries and oriented attachment

AU - Sayle, Thi X.T.

AU - Inkson, Beverley J.

AU - Karakoti, Ajay

AU - Kumar, Amit

AU - Molinari, Marco

AU - Möbus, Günter

AU - Parker, Stephen C.

AU - Seal, Sudipta

AU - Sayle, Dean C.

PY - 2011/4/1

Y1 - 2011/4/1

N2 - We predict that the presence of extended defects can reduce the mechanical strength of a ceria nanorod by 70%. Conversely, the pristine material can deform near its theoretical strength limit. Specifically, atomistic models of ceria nanorods have been generated with full microstructure, including: growth direction, morphology, surface roughening (steps, edges, corners), point defects, dislocations and grain-boundaries. The models were then used to calculate the mechanical strength as a function of microstructure. Our simulations reveal that the compressive yield strengths of ceria nanorods, ca. 10 nm in diameter and without extended defects, are 46 and 36 GPa for rods oriented along [211] and [110] respectively, which represents almost 10% of the bulk elastic modulus and are associated with yield strains of about 0.09. Tensile yield strengths were calculated to be about 50% lower with associated yield strains of about 0.06. For both nanorods, plastic deformation was found to proceed via slip in the {001} plane with direction 〈110〉 - a primary slip system for crystals with the fluorite structure. Dislocation evolution for the nanorod oriented along [110] was nucleated via a cerium vacancy present at the surface. A nanorod oriented along [321] and comprising twin-grain boundaries with {111} interfacial planes was calculated to have a yield strength of about 10 GPa (compression and tension) with the grain boundary providing the vehicle for plastic deformation, which slipped in the plane of the grain boundary, with an associated 〈110〉 slip direction. We also predict, using a combination of atomistic simulation and DFT, that rutile-structured ceria is feasible when the crystal is placed under tension. The mechanical properties of nanochains, comprising individual ceria nanoparticles with oriented attachment and generated using simulated self-assembly, were found to be similar to those of the nanorod with grain-boundary. Images of the atom positions during tension and compression are shown, together with animations, revealing the mechanisms underpinning plastic deformation. For the nanochain, our simulations help further our understanding of how a crystallising ice front can be used to 'sculpt' ceria nanoparticles into nanorods via oriented attachment.

AB - We predict that the presence of extended defects can reduce the mechanical strength of a ceria nanorod by 70%. Conversely, the pristine material can deform near its theoretical strength limit. Specifically, atomistic models of ceria nanorods have been generated with full microstructure, including: growth direction, morphology, surface roughening (steps, edges, corners), point defects, dislocations and grain-boundaries. The models were then used to calculate the mechanical strength as a function of microstructure. Our simulations reveal that the compressive yield strengths of ceria nanorods, ca. 10 nm in diameter and without extended defects, are 46 and 36 GPa for rods oriented along [211] and [110] respectively, which represents almost 10% of the bulk elastic modulus and are associated with yield strains of about 0.09. Tensile yield strengths were calculated to be about 50% lower with associated yield strains of about 0.06. For both nanorods, plastic deformation was found to proceed via slip in the {001} plane with direction 〈110〉 - a primary slip system for crystals with the fluorite structure. Dislocation evolution for the nanorod oriented along [110] was nucleated via a cerium vacancy present at the surface. A nanorod oriented along [321] and comprising twin-grain boundaries with {111} interfacial planes was calculated to have a yield strength of about 10 GPa (compression and tension) with the grain boundary providing the vehicle for plastic deformation, which slipped in the plane of the grain boundary, with an associated 〈110〉 slip direction. We also predict, using a combination of atomistic simulation and DFT, that rutile-structured ceria is feasible when the crystal is placed under tension. The mechanical properties of nanochains, comprising individual ceria nanoparticles with oriented attachment and generated using simulated self-assembly, were found to be similar to those of the nanorod with grain-boundary. Images of the atom positions during tension and compression are shown, together with animations, revealing the mechanisms underpinning plastic deformation. For the nanochain, our simulations help further our understanding of how a crystallising ice front can be used to 'sculpt' ceria nanoparticles into nanorods via oriented attachment.

UR - http://www.scopus.com/inward/record.url?scp=79953739899&partnerID=8YFLogxK

U2 - 10.1039/c0nr00980f

DO - 10.1039/c0nr00980f

M3 - Article

VL - 3

SP - 1823

EP - 1837

JO - Nanoscale

JF - Nanoscale

SN - 2040-3364

IS - 4

ER -