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

Sayle, T.X.T., Inkson, B.J., Karakoti, A., Kumar, A., Molinari, M., Möbus, G., Parker, S.C., Seal, S., Sayle, D.C. (2011) Mechanical properties of ceria nanorods and nanochains; The effect of dislocations, grain-boundaries and oriented attachment. Nanoscale, 3 (4). pp. 1823-1837. ISSN 20403364 (ISSN). (doi:10.1039/c0nr00980f)

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 ã??110ã?? - 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 ã??110ã?? 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. © 2011 The Royal Society of Chemistry.

Item Type: Article
DOI/Identification number: 10.1039/c0nr00980f
Additional information: Unmapped bibliographic data: LA - English [Field not mapped to EPrints] J2 - Nanoscale [Field not mapped to EPrints] C2 - 21409243 [Field not mapped to EPrints] AD - Dept. Engineering and Applied Science, Cranfield University, Defence Academy of the United Kingdom, Shrivenham SN6 8LA, United Kingdom [Field not mapped to EPrints] AD - Advanced Materials Processing and Analysis Center, University of Central Florida, Orlando, FL 32816, United States [Field not mapped to EPrints] AD - NanoScience Technology Center, University of Central Florida, Orlando, FL 32816, United States [Field not mapped to EPrints] AD - Mechanical Materials and Aerospace Engineering, University of Central Florida, Orlando, FL 32816, United States [Field not mapped to EPrints] AD - Dept. of Chemistry, University of Bath, Claverton Down, Bath, Avon BA2 7AY, United Kingdom [Field not mapped to EPrints] AD - NanoLAB Centre, Dept. of Materials Science and Engineering, Sheffield University, Sheffield S1 3JD, United Kingdom [Field not mapped to EPrints] DB - Scopus [Field not mapped to EPrints]
Uncontrolled keywords: Atom positions, Atomistic models, Atomistic simulations, Bulk elastic moduli, Ceria nanoparticles, Compression and tension, Dislocation evolution, Effect of dislocations, Extended defect, Fluorite structure, Growth directions, Interfacial planes, Mechanical strength, Nanochains, Oriented attachment, Pristine materials, Slip direction, Slip system, Surface-roughening, Tensile yield strength, Tension and compression, Theoretical strength, Yield strain, Yield strength, Cerium, Cerium compounds, Crystal structure, Grain boundaries, Grain growth, Grain size and shape, Mechanical properties, Mechanisms, Microstructure, Nanoparticles, Nanorods, Oxide minerals, Plastic deformation, Point defects, Single crystals, Surface defects, Tensile strength, Yield stress, Edge dislocations, cerium, nanomaterial, adhesion, article, chemical model, chemical structure, chemistry, compressive strength, computer simulation, mechanical stress, particle size, ultrastructure, Young modulus, Adhesiveness, Cerium, Compressive Strength, Computer Simulation, Elastic Modulus, Models, Chemical, Models, Molecular, Nanostructures, Particle Size, Stress, Mechanical
Subjects: Q Science
Divisions: Faculties > Sciences > School of Physical Sciences > Functional Materials Group
Depositing User: Dean Sayle
Date Deposited: 27 Jan 2015 16:33 UTC
Last Modified: 29 May 2019 14:06 UTC
Resource URI: https://kar.kent.ac.uk/id/eprint/46781 (The current URI for this page, for reference purposes)
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