Atomistic-to-continuum description of edge dislocation core: Unification of the Peierls-Nabarro model with linear elasticity

ABSTRACTA theoretical study of edge dislocation locking by impurities in silicon is presented. Three groups of impurities are considered: (i) light atoms O, N, and C., (ii) large atoms Ga, and Ge, and (iii) small dopant atoms B, P, and Al. Based on impurity size effect model, these three groups produce distinct different dislocation locking effects. Atoms from the first group strongly bind with edge dislocations. The O, N, and C atmospheres are similar, with a slightly stronger occupancy probability for O and N in the vicinity of the dislocation core. For the second group, Ge loosely binds to dislocation and resists at most 1/3 of the separation shear stress that the first group can withstand. Germanium has only a small chance to reach the dislocation core. The third impurity group does not resist shear any separation stress from edge dislocations. Moreover, B and P atoms can not be trapped at all by edge dislocations. At a local atomic fraction of 10−4, edge dislocation-impurity binding energy varies from 0.008 eV/Å for P to 1.7 eV/Å for N and 1. 8 eV/Å for O. In addition, using molecular mechanics on system of 34552 atoms the self-energy of an edge dislocation was calculated and found equal to 156 meV/Å.

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The Site Preference of Alloying Element Zr in NiAl Dislocation Core and its Effects on Bond Characters

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.344.19 ◽

2013 ◽

Vol 344 ◽

pp. 19-26

Author(s):

Li Qun Chen ◽

Zheng Chen Qiu

Keyword(s):

Binding Energy ◽

Edge Dislocation ◽

Dislocation Core ◽

Dislocation Motion ◽

Partial Density ◽

Site Preference ◽

Alloying Element ◽

Dislocation Interaction ◽

High Temperature Alloys ◽

Potential Applications

NiAl is one kind of high-temperature alloys with broad potential applications in aerospace industry. Its mechanical properties are believed to be largely related to the dislocation behavior and impurity-dislocation interaction. In the paper we report first principles study of the alloying effect of Zr in the [10(010) edge dislocation core of NiAl. The binding energy of doping system decreases 3.77 eV when a Zr atom substituted for an Al, only decreases 1.06 eV with substitution for a Ni atom. The result of the binding energy shows that a Zr atom prefers to occupy an Al site in the dislocation core of NiAl. The analyses of the charge distribution, the interatomic energy and the partial density of states suggest that Zr will greatly enhance the interaction between Zr atom and neighboring host atoms, as well as that between host atoms. These results show that the alloying element Zr induced pinning effect on the edge dislocation motion is predicted, and could be helpful for understanding microscopic mechanisms of alloying-induce hardening in NiAl alloy.

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An Evaluation of Bonding States of BCC(Fe) Edge Dislocation Core by DV-Xα Cluster Method

Journal of the Japan Institute of Metals and Materials ◽

10.2320/jinstmet1952.65.9_852 ◽

2001 ◽

Vol 65 (9) ◽

pp. 852-857 ◽

Cited By ~ 1

Author(s):

Takeshi Fukuda ◽

Moritaka Hida ◽

Akira Sakakibara ◽

Yoshito Takemoto

Keyword(s):

Edge Dislocation ◽

Dislocation Core ◽

Cluster Method ◽

Alpha Cluster

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Interaction of Hydrogen Atom with Edge Dislocation in Pd and Ni

Journal of Metastable and Nanocrystalline Materials ◽

10.4028/www.scientific.net/jmnm.30.46 ◽

2018 ◽

Vol 30 ◽

pp. 46-51

Author(s):

Irina V. Zorya ◽

Gennady M. Poletaev ◽

Mikhail D. Starostenkov

Keyword(s):

Molecular Dynamics ◽

Hydrogen Atom ◽

Sorption Capacity ◽

Edge Dislocation ◽

Dislocation Core ◽

Hydrogen Impurity ◽

Hydrogen Atoms ◽

Energy Characteristics ◽

Method Of Molecular Dynamics ◽

Diffusion Of Hydrogen

The energy characteristics of interaction of hydrogen impurity with ½<110> edge dislocation in Pd and Ni were calculated by the method of molecular dynamics. It is shown that the dislocation is effective trap for hydrogen. At the same time the dislocation jogs increases its sorption capacity with respect to hydrogen, but reduces the diffusion mobility of hydrogen along the dislocation. The diffusion of hydrogen atoms in the dislocation region occurs mainly along the dislocation core. The energy of hydrogen migration along the dislocation, as our calculations have shown, is almost two times lower than in a defect-free crystal.

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