Atomistic Simulation of ZrNi Metallic Glasses Under Torsion Test

NANO ◽  
2017 ◽  
Vol 12 (08) ◽  
pp. 1750094 ◽  
Author(s):  
Po-Hsien Sung ◽  
Tei-Chen Chen ◽  
Cheng-Da Wu

ZrNi metallic glass alloy nanowires (NWs) under torsion are studied using molecular dynamics simulations based on the many-body embedded-atom potential. The effect of cooling rate on the deformation mechanism and mechanical properties of ZrNi NWs is evaluated in terms of shear strain, torque, potential energy and radial distribution function. Simulation results show that for slower cooling rates, the NWs have larger packing density, whereas for faster cooling rates, the packing density of atoms decreases. The amount of deformation increases with increasing torsional angle before it reaches a critical torsional angle ([Formula: see text]. The torque required for deformation and the [Formula: see text] value increase with decreasing cooling rate, indicating a larger mechanical strength. Localized shear bands concentrate at regions with high shear strains, leading to the formation of torsional buckling.

1992 ◽  
Vol 278 ◽  
Author(s):  
J. A. Rifkin ◽  
C. S. Becquart ◽  
D. Kim ◽  
P. C. Clapp

AbstractWe have carried out a series of atomistic simulations on arrays of about 10,000 atoms containing an atomically sharp crack and subjected to increasing stress levels. The ordered stoichiometric alloys B2 NiAl, B2 RuAl and A15 Nb3AI have been studied at different temperatures and stress levels, as well as the elements Al, Ni, Nb and Ru. The many body interactions used in the simulations were derived semi-empirically, using techniques related to the Embedded Atom Method. Trends in dislocation generation rates and crack propagation modes will be discussed and compared to experimental indications where possible, and some of the simulations will be demonstrated in the form of computer movies.


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.


Author(s):  
Igor A. Shelepev ◽  
Ayrat M. Bayazitov ◽  
Elena A. Korznikova

Among a wide variety of point defects, crowdions can be distinguished by their high energy of formation and relatively low migration barriers, which makes them an important agent of mass transfer in lattices subjected to severe plastic deformation, irradiation, etc. It was previously shown that complexes and clusters of crowdions are even more mobile than single interstitials, which opened new mechanisms for the transfer of energy and mass in materials under intense external impacts. One of the most popular and convenient methods for analyzing crowdions is molecular dynamics, where the results can strongly depend on the interatomic potential used in the study. In this work, we compare the characteristics of a crowdion in an fcc lattice obtained using two different interatomic potentials — the pairwise Morse potential and the many-body potential for Al developed by the embedded atom method. It was found that the use of the many-body potential significantly affects the dynamics of crowdion propagation, including the features of atomic collisions, the evolution of energy localization and the propagation path.


1997 ◽  
Vol 08 (06) ◽  
pp. 1217-1221 ◽  
Author(s):  
J. I. Akhter ◽  
K. Yaldram

Molecular dynamics studies of the temperature dependence of self diffusion coefficient of palladium has been carried out using the many body potential generated by the Embedded Atom Method of Daw and Baskes. These values as well as the results for activation energy are compared with similar results for other fcc metals.


2021 ◽  
Author(s):  
Truong Quoc Vo ◽  
BoHung Kim

The atomic structures and solidification point of silver nanoparticles (SNPs) are studied in aseries of molecular dynamics simulations based on the empirical embedded atom methods (EAM). Thesolidification point is calculated from the extracted potential energy during the cooling process, whereasthe atomic structures are analyzed using the common neighbor (CN) method. The results indicate that thestructures of the solidified SNPs are very sensitive to both the applied cooling rate and the particle size. Wefind the critical cooling rate where a glassy structure is observed. Below the critical rate, polycrystallinenanoparticles are formed, where the percentage of the close-packed structures, i.e., FCC and HCP, decreaseswith increasing cooling rate. Moreover, the proportion of those structures is always larger with a biggerparticle size for an identical applied cooling rate. The findings in this study provide useful information formany practical applications where the nanostructure strongly affects thermal management and operationalefficiency.


1990 ◽  
Vol 193 ◽  
Author(s):  
R. Pasianot ◽  
E. J. Savino ◽  
S. Rao ◽  
D. Farkas

For the class of materials in which covalent effects are important, there is still no simple and reliable scheme, adapted to computer simulations, that can handle angle de- pendent forces. Either they are based on the introduction of three body (or higher) [1] interactions, or demand unphysical behavior from the many body functions used [2,3]. In the first case, computer efficiency is considerably low due to the large amounts of calculations required; in the second case a negative curvature of the embedding function must be assumed for materials in which the Cauchy pressure is negative, and this is contrary to the current interpretations of that function.In the present work we derive a method to introduce many body shear forces, suited to computer simulations, which is free from the shortcomings mentioned above.


2021 ◽  
Author(s):  
Thomas E. Gartner III ◽  
Kelly M. Hunter ◽  
Eleftherios Lambros ◽  
Alessandro Caruso ◽  
Marc Riera ◽  
...  

For the last 50 years, researchers have sought molecular models that can accurately reproduce water’s microscopic structure and thermophysical properties across broad ranges of its complex phase diagram. Herein, molecular dynamics simulations with the many-body MB-pol model are performed to monitor the thermodynamic response functions and local structure of liquid water from the boiling point down to deeply supercooled temperatures at ambient pressure. The isothermal compressibility and isobaric heat capacity show maxima at ~223 K, in excellent agreement with recent experiments, and the liquid density exhibits a minimum at ~208 K. Furthermore, a local tetrahedral arrangement, where each water molecule accepts and donates two hydrogen bonds, is the most probable hydrogen-bonding topology at all temperatures. This work suggests that MB-pol may provide predictive capability for studies of liquid water’s physical properties across broad ranges of thermodynamic states.


1968 ◽  
Vol 111 (1) ◽  
pp. 392-416 ◽  
Author(s):  
K DIETRICH ◽  
K HARA

2020 ◽  
Author(s):  
Marc Riera ◽  
Alan Hirales ◽  
Raja Ghosh ◽  
Francesco Paesani

<div> <div> <div> <p>Many-body potential energy functions (PEFs) based on the TTM-nrg and MB-nrg theoretical/computational frameworks are developed from coupled cluster reference data for neat methane and mixed methane/water systems. It is shown that that the MB-nrg PEFs achieve subchemical accuracy in the representation of individual many-body effects in small clusters and enables predictive simulations from the gas to the liquid phase. Analysis of structural properties calculated from molecular dynamics simulations of liquid methane and methane/water mixtures using both TTM-nrg and MB-nrg PEFs indicates that, while accounting for polarization effects is important for a correct description of many-body interactions in the liquid phase, an accurate representation of short-range interactions, as provided by the MB-nrg PEFs, is necessary for a quantitative description of the local solvation structure in liquid mixtures. </p> </div> </div> </div>


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