Stability of Hollow Nanospheres: A Molecular Dynamics Study

2007 ◽  
Vol 129 ◽  
pp. 125-130 ◽  
Author(s):  
Alexander V. Evteev ◽  
Elena V. Levchenko ◽  
Irina V. Belova ◽  
Graeme E. Murch

Molecular dynamics simulation using the embedded-atom method is applied to study defect formation and distribution in a hollow Pd nanosphere. It is established that besides vacancies, which can nucleate on the inner or external surfaces, at the external surface, other defects (Shockley partial dislocations, twins and stacking faults) form due to its significant reconstruction by means of a/6〈112〉 shears of atomic rows. The density of the defects on the external surface grows with decreasing nanoshell size. It is demonstrated that Shockley partial dislocations can act as vehicles for the transfer of material from the external surface to the inner surface of the nanoshell thus leading to shrinking. It is shown that the vacancy concentration is higher near both surfaces than in the bulk of the nanoshell.

1988 ◽  
Vol 100 ◽  
Author(s):  
Davy Y. Lo ◽  
Tom A. Tombrello ◽  
Mark H. Shapiro ◽  
Don E. Harrison

ABSTRACTMany-body forces obtained by the Embedded-Atom Method (EAM) [41 are incorporated into the description of low energy collisions and surface ejection processes in molecular dynamics simulations of sputtering from metal targets. Bombardments of small, single crystal Cu targets (400–500 atoms) in three different orientations ({100}, {110}, {111}) by 5 keV Ar+ ions have been simulated. The results are compared to simulations using purely pair-wise additive interactions. Significant differences in the spectra of ejected atoms are found.


1989 ◽  
Vol 159 ◽  
Author(s):  
Cliff F. Richardson ◽  
Paulette Clancy

ABSTRACTThe ultra-rapid melting and subsequent resolidification of Embedded Atom Method models of the fcc metals copper and gold are followed using a Non-Equilibrium Molecular Dynamics computer simulation method. Results for the resolidification of an exposed (100) face of copper at room temperature are in good agreement with recent experiments using a picosecond laser. At T = 0.5 Tm, the morphology of the solid/liquid interface is shown to be similar to a Lennard-Jones model. The morphology of the crystal-vapor interface at 92% of Tm shows a significant disordering of the topmost layers. Difficulties with the EAM model for gold are observed. Comparison of the Baskes et al. and Oh and Johnson embedding functions are discussed.


2005 ◽  
Vol 475-479 ◽  
pp. 3291-3294
Author(s):  
Shi Fang Xiao ◽  
Yu Hu Wang

The uniaxial compressive mechanical properties of nanocrystalline Fe are simulated with a molecular dynamics technique and the analytical embedded-atom method. An asymmetrical mechanical phenomenon between tensile and compressive process is found, and the yield stress and flow stress in compression are higher than those in tension simulations. The compressive deformation process can be described as three characteristic regions: quasi-elastic deformation, plastic flowing deformation, and strain strengthening. During the plastic flowing deformation region, the material shows very good compressive ductibility. The plastic deformation is mainly dominated by the grain boundary atom slide.


Author(s):  
Y. H. Park ◽  
J. Tang

This paper describes the calculation of material properties of copper (Cu) using the molecular dynamics method. Vacancy formation energy, bulk modulus, surface energy and melting point are calculated using different potentials such as the Morse potential and Embedded Atom Method (EAM). Results obtained from different potentials are discussed and compared with experimental results.


2013 ◽  
Vol 643 ◽  
pp. 116-119
Author(s):  
Teng Fang ◽  
Li Wang ◽  
Yu Qi

Molecular dynamics simulation has been performed to explore the thermodynamics and dynamics properties of liquid Cu-Ni alloy based upon developed embedded atom methods (EAM), namely due to G. Bonny. The calculated liquid density shows that the potential underestimates the measured atomic density for Ni-rich composition. The calculated mixing enthalpy predicts the potential underestimates the mixing enthalpy when the concentration of Ni is increased beyond roughly 30 at. %. We make a conclusion from the fact that the G. Bonny’s model is not full perfect in describing the density and mixing enthalpy of Cu-Ni melts at the Ni-rich composition.


2019 ◽  
Vol 87 (3) ◽  
pp. 31301 ◽  
Author(s):  
Hicham El Azrak ◽  
Abdessamad Hassani ◽  
Abdelhadi Makan ◽  
Fouad Eddiai ◽  
Khalid Sbiaai ◽  
...  

In this paper, molecular dynamics (MD) simulation of surface morphology during homoepitaxial growth of Copper was investigated. For this purpose, simulations of Cu deposition on the Cu(111) substrate with an incidence energy of 0.06 eV at 300K were performed using the embedded-atom method (EAM). The grown thin film on Cu(111) reveled a rough surface morphology. During deposition, the important fraction of atoms intended for the upper layers undergone a rising rate of about 40% starting from the 2nd period and continued to increase until 65%, while the lower level reached a permanent rate of only 25% by the 4th period. Otherwise, except at the first layer level, the lower layers are incomplete. This void in the lower layers has favored the growth of the upper layers until a rate of 143% and has accelerated their time appearance. Th incidence energy has favored the filling of lower layers by reducing this surface roughness. However, the temperature effect needs more relaxation time to fill the lower layers.


2010 ◽  
Vol 638-642 ◽  
pp. 1665-1670 ◽  
Author(s):  
Jian Jun Pang ◽  
Ming Jen Tan ◽  
Anders W.E. Jarfors ◽  
P.D. Chuang

Ti-based metallic glasses (MGs) due to their relative low densities exhibit ultrahigh specific characteristics. In this article the glass-forming behavior and atomic structure of Ti50Cu50 MG were investigated through molecular dynamics simulation (MDS) using the general embedded-atom method (GEAM) potential. As observed experimentally, simulated Ti50Cu50 alloy undergoes three states on quenching: (i) equilibrium liquid; (ii) supercooled liquid and (iii) glassy solid. The atomic configuration of the glass was analysed based on the radial distribution function (RDF) and Voronoi tessellation (VT). It was found that there exist a variety of polyhedral units in Ti50Cu50 MG, where distorted icosohedral and bcc clusters are dominant.


2004 ◽  
Vol 818 ◽  
Author(s):  
S. Kameoka ◽  
K. Shintani

AbstractThe deformation of Au nanowires of helical multi-shell (HMS) structures and the fcc structure under a tensile external force is addressed by molecular-dynamics simulation. The modified embedded-atom method (MEAM) potential is employed for calculating the interaction between Au atoms. At first, a model nanowire is equilibrated at a specified temperature. Next, the external force in the axial direction is imposed on the Au atoms at the ends of the nanowire. We conclude that the Young modulus of a Au nanowire depends on its atomic structure.


2009 ◽  
Vol 417-418 ◽  
pp. 21-24
Author(s):  
Shu Sheng Xu ◽  
Xiang Guo Zeng ◽  
Hua Yan Chen

The crack propagation for pure Magnesium at an atomic scale level under external loading was carried out by using a molecular dynamics method. In this study, the Modified Embedded Atom Method (MEAM) was used to characterize the interactions of atoms and the Newtonian equations were solved by Velocity-Verlet algorithm. The crack propagation and failure processes were observed around the crack tip. The calculation results reveal that vacancies were formed near the crack tip during the failure processes for pure Magnesium, and the coalescence between crack tip and vacancies induced the crack growth with the increase in loading.


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