Role of point defects in self-diffusion along low-angle twist boundaries in fcc metals: A molecular dynamics study

2018 ◽  
Vol 03 (01n02) ◽  
pp. 1850001 ◽  
Author(s):  
G. M. Poletaev ◽  
I. V. Zorya ◽  
M. D. Starostenkov
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Point Defects ◽  
Binding Energies ◽  
Fcc Metals ◽  
Self Diffusion ◽  
Thermodynamic Equilibrium Condition ◽  
Dynamics Method ◽  
Twist Boundaries

The interaction of point defects with low-angle (100), (110) and (111) twist boundaries in fcc metals Ni, Cu, Al and role of the point defects in self-diffusion along considered boundaries were studied by the molecular dynamics method. The binding energies of point defects with low-angle twist boundaries were calculated. It was found that the point defects are mainly fixed in the nodes of grain-boundary screw dislocations network. It was shown that the introduced vacancies play an important role in diffusion along twist grain boundaries. The contribution of introduced interstitial atoms to grain-boundary diffusion under thermodynamic equilibrium condition is less by several orders of magnitude in comparison with the contribution of vacancies.

Simulation of Surface Diffusion Using Embedded Atom Potentials in FCC Metals

1996 ◽  
Vol 440 ◽  
Author(s):  
Jun-Ichiro Takano ◽  
Masao Doyama ◽  
Yoshiaki Kogure
Keyword(s):  
Molecular Dynamics ◽  
Binding Energy ◽  
Surface Diffusion ◽  
Binding Energies ◽  
Fcc Metals ◽  
Embedded Atom ◽  
Gold Silver ◽  
Copper Adatoms ◽  
Atom Potential ◽  
Dynamics Method

AbstractThe binding energies of gold, silver and copper adatoms and their clusters to each (111) surface have been calculated. The binding energy EN of an N-adatom cluster can be roughly written as EN=3NE1+mE2, where 3E1, is the binding energy of a single adatom to the (111) surface and m is the number of bonds within the cluster and E2 is the binding energy of the bond within the cluster. It was found that E1=0.95eV, E2=0.42–0.49eV for gold, E1=0.62eV, E2=0.38-0.44eV for silver and E1=0.81eV, E2=0.43–0.49eV for copper (by use of a newly determined N-body embedded atom potential). The activation energies of motion of these adatom clusters on each (111) surfaces have been calculated by use of a newly determined N-body embedded atom potential and molecular dynamics method.

scholarly journals Tight-Binding Molecular Dynamics Simulations on Point Defects Diffusion and Interactions in Crystalline Silicon

1995 ◽  
Vol 396 ◽  
Author(s):  
M. tang ◽  
L. colombo ◽  
T. Diaz De La Rubia
Keyword(s):  
Molecular Dynamics ◽  
Molecular Dynamics Simulations ◽  
Point Defects ◽  
Crystalline Silicon ◽  
Tight Binding ◽  
Diffusion Path ◽  
Binding Energies ◽  
Defect Clusters ◽  
Dynamics Simulations

AbstractTight-binding molecular dynamics (TBMD) simulations are performed (i) to evaluate the formation and binding energies of point defects and defect clusters, (ii) to compute the diffusivity of self-interstitial and vacancy in crystalline silicon, and (iii) to characterize the diffusion path and mechanism at the atomistic level. In addition, the interaction between individual defects and their clustering is investigated.

Structural and Mechanical Properties of Nanophase Ni: A Molecular-Dynamics Study of the Influence of Grain-Boundary Structure on Elastic and Plastic Behavior

1997 ◽  
Vol 492 ◽  
Author(s):  
H. Van Swygenhoven ◽  
M. Spaczér ◽  
A. Caro
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Diffusion Mechanism ◽  
Distribution Functions ◽  
Boundary Structure ◽  
Plastic Behavior ◽  
Self Diffusion ◽  
Common Neighbour ◽  
Grain Boundary Structure

ABSTRACTMolecular dynamics computer simulations of high load plastic deformation at temperatures up to 500K of Ni nanophase samples with mean grain size of 5 nm are reported. Two types of samples are considered: a polycrystal nucleated from different seeds, each having random location and random orientation, representing a sample with mainly high angle grain boundaries, and polycrystals with seeds located at the same places as before, but with a limited missorientation representing samples with mainly low angle grain boundaries. The structure of the grain boundaries is studied by means of pair distribution functions, coordination number, atom energetics, and common neighbour analysis. Plastic behaviour is interpreted in terms of grain-boundary viscosity, controlled by a self diffusion mechanism at the disordered interface activated by thermal energy and stress.

Self Diffusion in SiC: the Role of Intrinsic Point Defects

2001 ◽  
Vol 353-356 ◽  
pp. 323-326 ◽  
Author(s):  
Alexander Mattausch ◽  
M. Bockstedte ◽  
Oleg Pankratov
Keyword(s):  
Point Defects ◽  
Intrinsic Point Defects ◽  
Self Diffusion

scholarly journals Molecular Dynamics Study of Interaction of Carbon, Nitrogen, and Oxygen Impurity Atoms with Self-Interstitial Atoms in Nickel, Silver and Aluminum

2021 ◽  
pp. 27-32
Author(s):  
I.V. Zorya ◽  
G.M. Poletaev
Keyword(s):  
Molecular Dynamics ◽  
Impurity Atom ◽  
Interstitial Atom ◽  
Binding Energies ◽  
Oxygen Impurity ◽  
Impurity Atoms ◽  
Nickel Silver ◽  
Interstitial Atoms ◽  
Atom Migration ◽  
Dynamics Method

The interaction of impurity atoms of carbon, nitrogen, and oxygen with self-interstitial atoms in FCC metals like nickel, silver, and aluminum is studied using the molecular dynamics method. It is found that the self-interstitial atom migration in the crystal lattice follows two mechanisms: dumbbell and crowdion. In this case, the first mechanism that includes one interatomic distance displacement and the rotation of the <001> dumbbell is characterized by broken paths of atomic migration. The second mechanism is described by straight paths along the close-packed directions <011> in the crystal. The binding energies between impurity atoms and selfinterstitial atoms in Ni, Ag, and Al are calculated in the paper. It is shown that impurity atoms are effective “traps” for interstitial atoms that migrate relatively quickly in a crystal. During the interaction of an interstitial and an impurity atom, the interstitial atom forms a dumbbell configuration with an axis along the <001> direction, and the impurity atom is located in the nearest octahedral pore. It is found that the mobility of interstitial atoms is significantly reduced due to the presence of impurities in the metal. The introduction of 10 % impurity atoms leads to a severalfold increase in the migration energy of interstitial atoms. At the same time, the contribution of the crowdion mechanism is noticeably reduced while the dumbbell mechanism contribution is increased.

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