While metal nanoparticles are widely used, their small size makes them mechanically unstable. Extensive prior research has demonstrated that with sizes in the range of 10–50 nm fail by surface nucleation dislocations, which is a thermally activated process. Two different contributions have been suggested to cause weakening smaller particles: first, geometric effects such as increased curvature reduce barrier for dislocation nucleation; second, diffusion happens faster on particles, thus...

While it is well established that nanoparticle shape can depend on equilibrium thermodynamics or growth kinetics, recent computational work has suggested the importance of thermal energy in controlling distribution shapes populations nanoparticles. Here, we used transmission electron microscopy to characterize bare platinum nanoparticles and observed a strong dependence particle size. Specifically, smallest (<2.5 nm) had truncated octahedral shape, bound by 〈111〉 〈100〉 facets, as predicted...

The mechanical behavior of nanostructures is known to transition from a Hall-Petch-like "smaller-is-stronger" trend, explained by dislocation starvation, an inverse Hall-Petch "smaller-is-weaker" typically attributed the effect surface diffusion. Yet recent work on platinum nanowires demonstrated persistence smaller-is-stronger down few-nanometer diameters. Here, we used in situ nanomechanical testing inside transmission electron microscope (TEM) study strength and deformation mechanisms...

The mechanical behavior of nanoparticles governs their performance and stability in many applications. However, the small sizes technologically relevant nanoparticles, with diameters range 10 nm or less, significantly complicate experimental examination. These are difficult to manipulate onto commercial test platforms deform at loads that below typical noise floor testing instruments. Here, we synthesized platinum directly a tester used modified nanomanipulator enhance load resolution...

The elastic behavior of nanoparticles depends strongly on particle shape, size, and crystallographic orientation. Many prior investigations have characterized the modulus nanoscale particles using experiments or simulations; however their reported values vary widely depending methods for measurement calculation. To understand these discrepancies, we used classical molecular dynamics simulation to model compression platinum with two different polyhedral shapes a range sizes from 4 20 nm,...

Understanding the size- and shape-dependent properties of platinum nanoparticles is critical for enabling design nanoparticle-based applications with optimal potentially tunable functionality. Toward this goal, we evaluated nine different empirical potentials purpose accurately modeling faceted using molecular dynamics simulation. First, were by computing bulk surface properties-surface energy, lattice constant, stiffness constants, equation state-and comparing these to prior experimental...

Cement paste is a material with heterogeneous composite structure consisting of hydrated and unhydrated phases at all length scales that varies depending upon the degree hydration. In this paper, method to model cement as multiphase system molecular level for predicting constitutive properties understanding mechanical behavior characteristics using dynamics presented. The proposed creates framework models suitable could provide potential comparisons low scale experimental characterization...

One-Dimensional nanostructures are of great importance due to their unique electrical, magnetic and mechanical properties. Because the size constraints, it is impractical obtain understand properties, deformation behavior associated mechanisms experimentally, while atomistic computational modeling offers a viable approach. Several studies have focused on pure metallic compound nanowires; however, investigations data for core–shell nanowires still very limited. Present work models analyzes...

The complex composite material cement paste (CP) is under high pressures in underwater applications and when impact loading occurs. mechanical behavior of to hydrostatic compression results from deformations each phase, including unhydrated hydrated minerals. Molecular Dynamics was used study the atomistic deformation individual phases with increasing pressures. pressure-specific volume Birch-Murnaghan equation state (EoS) bulk modulus at zero pressure were determined for phase. Results show...

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Los nanotubos de carbono son una las nanoestructuras más usadas para el desarrollo nuevos nanodispositivos debido a sus excepcionales propiedades mecánicas, ópticas, químicas y eléctricas. En este trabajo, método multiescala llamado mecánica molecular estructural se usó estimar módulo Young frecuencias naturales diferentes quiralidades tamaños. Este establece un enlace entre lamecánica con la clásica por medio balances energía permite reducir tiempo procesamiento en comparación otros...

Molybdenum carbide has various applications for which studying the material using classical molecular dynamics simulations would be valuable. Here, we develop an empirical potential within Tersoff formalism particle swarm optimization orthorhombic phase of Mo2C. The developed is shown to predict lattice constants, elastic properties, and equation state results that are consistent with current previously reported from experiments first principles calculations. We demonstrate indentation...