On a correlation between the hydrogen effects on atomic interactions and mobility of grain boundaries in the alpha-iron. Stage I. A change in the electron structure of the alpha-iron due to hydrogen

2020 ◽  
Vol 258 ◽  
pp. 126801 ◽  
Author(s):  
S.M. Teus ◽  
V.G. Gavriljuk
Keyword(s):  
Grain Boundaries ◽  
Electron Structure ◽  
Stage I ◽  
Alpha Iron ◽  
Atomic Interactions

Atomie and Electron Structure of Diamond Grain boundaries in a Polycrystalline Film

1997 ◽  
Vol 472 ◽  
Author(s):  
Hideki Ichinose ◽  
Megumi Nakanose ◽  
Yaogan Zhang
Keyword(s):  
Grain Boundaries ◽  
Polycrystalline Diamond ◽  
High Resolution Electron Microscopy ◽  
Electron Structure ◽  
Polished Surface ◽  
Resolution Electron ◽  
Diamond Grain ◽  
Electron Energy Loss ◽  
Π State ◽  
Polycrystalline Diamond Film

AbstractA polycrystalline diamond film was grown on the polished surface of silicon substrate in H2-CO-O2 mixing gas. Atomic and electron structure of grain boundaries in the film was investigated by both high resolution electron microscopy and electron energy loss spectroscopy. CSL boundaries in the film showed characteristic feature in atomic structure; Σ 9 CSL boundary was parallel not to (221) plane but to (114) plane. A new line which correspond to π * state was found in addition to major σ * line in the EELS spectra of the boundary which contained three coordinate atoms. Observed π * line shows occurred change of a dangling bond (pz electron) to π state. No π * line appeared in the EELS spectra obtained from boundaries which contained no three coordinate atom such as (111) Σ 3 boundary.

Atomistic Modeling of Extended Defects in Metalic Alloys: Dislocations and Grain Boundaries in Ll2 Compounds

1990 ◽  
Vol 186 ◽  
Author(s):  
V. Vitek ◽  
G. J. Ackland ◽  
J. Cserti
Keyword(s):  
Grain Boundaries ◽  
Dislocation Core ◽  
Extended Defects ◽  
Atomistic Modeling ◽  
Many Body ◽  
Deformation And Fracture ◽  
Governing Factor ◽  
Atomic Interactions ◽  
Total Energies ◽  
Physical Features

AbstractExtended defects, such as dislocations and grain boundaries, control a wide variety of material properties and their atomic structure is often a governing factor. A necessary precursor for modeling of these structures is a suitable description of atomic interactions. We present here empirical many-body potentials for alloys which represent a very simple scheme for the evaluation of total energies and yet reflect correctly the basic physical features of the alloy systems modeled. As examples of atomistic studies we show results of calculations of the core structures of screw dislocations in Ll2 compounds. The same potentials have also been used to calculate structures of grain boundaries in these compounds. The deformation and fracture behavior of Ll2 alloys is then discussed in the light of grain boundary and dislocation core studies.

ATOMIC AND ELECTRON STRUCTURE OF GRAIN BOUNDARIES IN SILICON

1990 ◽  
Vol 51 (C1) ◽  
pp. C1-71-C1-76 ◽  
Author(s):  
A. V. ARTEMYEV ◽  
L. E. POLYAK ◽  
L. K. FIONOVA
Keyword(s):  
Grain Boundaries ◽  
Electron Structure

A Comparative Atomistic Study of the Structure of Grain Boundaries in Tungsten

1992 ◽  
Vol 291 ◽  
Author(s):  
A. Marinopoulos ◽  
M. Sob ◽  
V. Vitek ◽  
A. E. Carlsson
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Structural Characteristics ◽  
Many Body ◽  
Electronic Density ◽  
Atomic Interactions ◽  
Symmetrical Tilt ◽  
Tilt Grain Boundary ◽  
Atomistic Study ◽  
Central Forces

ABSTRACTMost atomistic studies of grain boundaries have been carried out using central forces to describe atomic interactions. However, in transition metals with unfilled d-bands the angular dependence of interatomic forces may be important. The purpose of this paper is to investigate the significance of angular forces in the case of Tungsten. The calculations have been performed for the Σ5(210) symmetrical tilt grain boundary using two alternate approaches. First are the central-force many-body potentials of the Finnis-Sinclair type. The second are the angular dependent potentials obtained via a moment analysis of the electronic density of states. The results of these two approaches are compared by analyzing the boundary structures, the relative displacements of the adjoining grains and the expansion. Differences in structural characteristics are discussed in terms of the effect of angular forces.

Simulation of Recrystallization Using Molecular Dynamics; Effects of the Interatomic Potential

2007 ◽  
Vol 558-559 ◽  
pp. 1081-1086 ◽  
Author(s):  
Rasmus B. Godiksen ◽  
Zachary T. Trautt ◽  
Moneesh Upmanyu ◽  
Søren Schmidt ◽  
Dorte Juul Jensen
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Interatomic Potential ◽  
Driving Forces ◽  
Boundary Migration ◽  
Grain Boundary Migration ◽  
High Angle ◽  
Embedded Atom ◽  
Atomic Interactions

Recrystallization is governed by the migration of high angle grain boundaries traveling through a deformed material driven by the excess energy located primarily in dislocation structures. A method for investigating the interaction between a migrating grain boundary and dislocation boundaries using molecular dynamics (MD) was recently developed. During simulations migrating high angle grain boundaries interact with dislocation boundaries, and individual dislocations from the dislocation boundaries are absorbed into the grain boundaries. Results obtained previously, using a simple Lennard-Jones (LJ) potential, showed surprisingly irregular grain boundary migration compared to simulations of grain boundary migration applying other types of driving forces. Inhomogeneous boundary-dislocation interactions were also observed in which the grain boundaries locally acquired significant cusps during dislocation absorption events. The study presented here makes comparisons between simulations performed using a LJ- and an embedded atom method (EAM) aluminum potential. The results show similarities which indicate that it is the crystallographic features rather than the atomic interactions that determine the details of the migration process.

Segregation and Phase Transitions in Grain Boundaries

2019 ◽  
Vol 22 ◽  
pp. 160-169
Author(s):  
Boris Bokstein ◽  
Alexey Rodin ◽  
Aleksei Itckovich ◽  
Leonid Klinger
Keyword(s):  
Phase Transition ◽  
Phase Transitions ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Computer Modeling ◽  
Boundary Segregation ◽  
Short Description ◽  
Grain Boundary Segregation ◽  
Atomic Interactions

The paper is devoted to some properties of grain boundaries: Segregation and concentration phase transitions – two important consequences of atomic interactions in grain boundaries. Except of a short description the Gibbs method of surface excesses and grain boundary segregation isotherms with the limited number of segregation sites in grain boundary, the paper concentrates on the effects of complexes formation, including thermodynamic and computer modeling, and concentration phase transition in the grain boundaries in systems with restricted solubility and intermediate compounds.

Intergranular fracture at migrating and sliding grain boundaries in an alpha iron - tin alloy

1981 ◽  
Vol 15 (9) ◽  
pp. 965-970 ◽  
Author(s):  
Tadao Watanabe ◽  
Minoru Obata ◽  
Seiichi Karashima
Keyword(s):  
Grain Boundaries ◽  
Intergranular Fracture ◽  
Alpha Iron
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