The stability of hollow nanoparticles and the simulation temperature ramp

Reyes, Paula N.; Valencia, Felipe J.; Vega, Héctor; Ruestes, Carlos J.; Rogan, José; Valdivia, J. A.; Kiwi, Miguel

doi:10.1039/c7qi00822h

Cited by 10 publications

(30 citation statements)

References 46 publications

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“…This criterion was chosen based on Cao et al 21 findings, which show a strong surface reorientation when the NT thickness is close to 1 nm. We note that this behavior has also been observed in other hollow structures 49 – 51 , for a specific combination of radius and thickness. In those cases, the surface stress is not compensated by the shell, originating a partial shrinkage, and the surface reorientation is assisted by Shockley partial dislocations as the dominant mechanism.…”

Section: Methodssupporting

confidence: 79%

Polycrystalline Ni nanotubes under compression: a molecular dynamics study

Rojas-Nunez

Baltazar

González

et al. 2020

Sci Rep

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Mechanical properties of nanomaterials, such as nanowires and nanotubes, are an important feature for the design of novel electromechanical nano-architectures. Since grain boundary structures and surface modifications can be used as a route to modify nanostructured materials, it is of interest to understand how they affect material strength and plasticity. We report large-scale atomistic simulations to determine the mechanical response of nickel nanowires and nanotubes subject to uniaxial compression. Our results suggest that the incorporation of nanocrystalline structure allows completely flexible deformation, in sharp contrast with single crystals. While crystalline structures at high compression are dominated by dislocation pinning and the multiplication of highly localized shear regions, in nanocrystalline systems the dislocation distribution is significantly more homogeneous. Therefore, for large compressions (large strains) coiling instead of bulging is the dominant deformation mode. Additionally, it is observed that nanotubes with only 70% of the nanowire mass but of the same diameter, exhibit similar mechanical behavior up to 0.3 strain. Our results are useful for the design of new flexible and light-weight metamaterials, when highly deformable struts are required.

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Section: Methodssupporting

confidence: 79%

Polycrystalline Ni nanotubes under compression: a molecular dynamics study

Rojas-Nunez

Baltazar

González

et al. 2020

Sci Rep

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“…On the one hand, excess energy due to the grain boundary structure can trigger the grain boundary sliding and the shrinkage of the NS [48]. On the other hand, while typical Au hollow nanospheres with thicknesses of 5 nm and diameters of 50 nm are stable at room temperature [52][53][54], the porous structure of the NS increases the surface area, which can drive the collapse of the nanostructure due to surface stresses [48]. Therefore, we adopted a relaxation time of 10 ns using a timestep of 1.0 fs at 400 K. Then, the system temperature was cooled to 300 K, in 0.1 ps with a time step of 1.0 fs.…”

Section: Methodsmentioning

confidence: 99%

Probing the Mechanical Properties of Porous Nanoshells by Nanoindentation

et al. 2022

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In this contribution, we present a study of the mechanical properties of porous nanoshells measured with a nanoindentation technique. Porous nanoshells with hollow designs can present attractive mechanical properties, as observed in hollow nanoshells, but coupled with the unique mechanical behavior of porous materials. Porous nanoshells display mechanical properties that are dependent on shell porosity. Our results show that, under smaller porosity values, deformation is closely related to the one observed for polycrystalline and single-crystalline nanoshells involving dislocation activity. When porosity in the nanoparticle is increased, plastic deformation was mediated by grain boundary sliding instead of dislocation activity. Additionally, porosity suppresses dislocation activity and decreases nanoparticle strength, but allows for significant strain hardening under strains as high as 0.4. On the other hand, Young’s modulus decreases with the increase in nanoshell porosity, in agreement with the established theories of porous materials. However, we found no quantitative agreement between conventional models applied to obtain the Young’s modulus of porous materials.

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“…Las W-hNPs fueron construidas a partir de <100> W, seleccionando dos esferas concéntricas de 5,0 y 7,5 nm de radio, obteniendo como resultado una W-hNP completamente cristalina, con un radio externo de 7,5 nm y un espesor de 2,5 nm (detallada en la Figura 7.1). Este proceso ha sido empleado en otras ocasiones para analizar la estabilidad de W-hNPs, confirmándose los resultados obtenidos con medidas experimentales [85,243,244]. Las W-hNPs simuladas siguieron un proceso de relajación por calentamiento para eliminar tensiones residuales [243].…”

Section: Simulaciones Atomísticasunclassified

“…Este proceso ha sido empleado en otras ocasiones para analizar la estabilidad de W-hNPs, confirmándose los resultados obtenidos con medidas experimentales [85,243,244]. Las W-hNPs simuladas siguieron un proceso de relajación por calentamiento para eliminar tensiones residuales [243]. El estudio de la estabilidad térmica se llevó a cabo aumentando la temperatura de la W-hNP diseñada desde un valor inicial de 300 K hasta alcanzar 3000 K en pasos de 20 K cada 0,2 ns, empleando para ello un termostato Noose-Hoover con un paso de tiempo de 1 fs.…”

Section: Simulaciones Atomísticasunclassified

“…El análisis estructural mediante el método de la plantilla de correspondencia poliédrica reveló que las nanopartículas retienen su estructura BCC, estructura esférica y radio a temperaturas superiores a las típicamente encontradas en la ventana experimental de trabajo de un PFM. La estructura BCC subyacente, que obstaculiza el deslizamiento de planos preferenciales y la nucleación de dislocaciones de Shockley a baja energía puede explicar la resiliencia de estas W-hNPs a altas temperaturas, identificándose estos mecanismos como los precursores primordiales del colapso de nanopartículas FCC [243,244,250].…”

Section: Efecto De La Temperatura Y La Presión En Nanopartículas Huecasunclassified

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Especies ligeras en materiales de interés para aplicaciones energéticas

Rodríguez¹

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En primer lugar, quiero dar las gracias a mis directores de tesis, Antonio Rivera y Ovidio Peña, así como al director del Instituto de Fusión Nuclear "Guillermo Velarde" (UPM), Jose Manuel Perlado, por darme la oportunidad de realizar este proyecto, por la ayuda recibida a lo largo de la tesis y todo el trabajo realizado.Estoy muy agradecido a Francisco Muñoz y a Rafael González, que hicieron posible mi estancia doctoral en Chile. Tanto el viaje como la experiencia fueron inolvidables.

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The stability of hollow nanoparticles and the simulation temperature ramp

Abstract: Hollow nanoparticles (hNPs) are of interest because their large cavities and small thickness give rise to a large surface to volume ratio.

Cited by 10 publications

References 46 publications

Polycrystalline Ni nanotubes under compression: a molecular dynamics study

Polycrystalline Ni nanotubes under compression: a molecular dynamics study

Probing the Mechanical Properties of Porous Nanoshells by Nanoindentation

Especies ligeras en materiales de interés para aplicaciones energéticas

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