Comparison Between Atomistic and Continuum-Mechanics Modelling of Grain-Boundary Fracture

1997 ◽  
Vol 492 ◽  
Author(s):  
F. Cleri ◽  
S. R. Phillpot ◽  
D. Wolf
Keyword(s):  
Grain Boundary ◽  
Continuum Mechanics ◽  
Dislocation Nucleation ◽  
Atomistic Simulations ◽  
Interface Plane ◽  
Dislocation Emission ◽  
Mechanics Model ◽  
Symmetric Tilt ◽  
Dynamics Simulations ◽  
Boundary Fracture

ABSTRACTWe use the Peierls-Nabarro continuum mechanics model of dislocation nucleation, modified according to the results of atomistic simulations, to interpret the experimental results of fracture response in symmetric-tilt grain boundaries in Cu. We then directly perform Molecular Dynamics simulations of fracture propagation and dislocation emission from a microcrack placed in the interface plane of the symmetric-tilt (221)(221) grain boundary in fee Cu. Direction-dependent fracture response is observed in agreement with experiments, namely the microcrack advancing by brittle fracture along the [114] direction and being blunted by dislocation emission along the opposite [114] direction. Moreover, we are able to quantify important differences with respect to the continuum model due to the shielding of the stress field at the crack-tip and to the presence of the excess stress at the interface.

scholarly journals Grain Boundary Fracture in Molybdenum Bicrystals with Various ⟨110⟩ Symmetric Tilt Boundaries

1985 ◽  
Vol 26 (5) ◽  
pp. 341-352 ◽  
Author(s):  
Hiroaki Kurishita ◽  
Akira Ôishi ◽  
Haruyoshi Kubo ◽  
Hideo Yoshinaga
Keyword(s):  
Grain Boundary ◽  
Symmetric Tilt ◽  
Tilt Boundaries ◽  
Grain Boundary Fracture ◽  
Boundary Fracture

Atomistic Modeling of Grain Boundary Fracture in Diamond

1998 ◽  
Vol 539 ◽  
Author(s):  
O.A. Shenderova ◽  
D.W. Brenner ◽  
A. Omeltchenko ◽  
X. Su ◽  
L. Yang
Keyword(s):  
Grain Boundary ◽  
Polycrystalline Diamond ◽  
Atomistic Modeling ◽  
Crack Behavior ◽  
Bond Order Potential ◽  
Symmetrical Tilt ◽  
Grain Boundary Fracture ◽  
Dynamics Simulations ◽  
Cohesive Energies ◽  
Boundary Fracture

AbstractMolecular dynamics simulations using a bond-order potential were carried out to investigate the behavior under load of several <001> and <011> symmetrical tilt grain boundaries in diamond. Cohesive energies, work for fracture, maximum stresses and strains as functions of the type of grain boundary were evaluated. It was found that special short-periodic GBs possess higher strength and resistance to a crack propagation than GBs in the nearby misorientation range. Crack behavior in polycrystalline diamond samples under an applied load was also simulated, and found to be predominantly transgranular.

Effect of Crack on the Tensile Strength of a Bicrystal Zr - A MD Based Evaluation

2020 ◽  
Vol 978 ◽  
pp. 487-491
Author(s):  
Divya Singh ◽  
Avinash Parashar
Keyword(s):  
Molecular Dynamics ◽  
Tensile Strength ◽  
Grain Boundary ◽  
Tensile Loading ◽  
Strain Response ◽  
Tilt Axis ◽  
Symmetric Tilt ◽  
Tilt Grain Boundary ◽  
The One ◽  
Dynamics Simulations

In this article, molecular dynamics simulations have been performed to study the effect of crack on the tensile strength of a bicrystal of Zr. Bicrystal with a symmetric tilt grain boundary, with crack and without crack, are generated along [0001] tilt axis. This is further subjected to tensile loading and the stress strain response of the bicrystals with and without crack is studied. The strength of the bicrystal with crack is lower than the one without crack.

Atomistic Aspects of Crack Propagation Along High Angle Grain Boundaries

1996 ◽  
Vol 460 ◽  
Author(s):  
Diana Farkas
Keyword(s):  
Grain Boundary ◽  
Atomistic Simulations ◽  
High Angle ◽  
Brittle Behavior ◽  
Embedded Atom ◽  
Tilt Boundaries ◽  
Symmetrical Tilt ◽  
Grain Boundary Fracture ◽  
Tilt Grain Boundary ◽  
Boundary Fracture

ABSTRACTWe present atomistic simulations of the crack tip configuration near a high angle Σ= 5 [001](210) symmetrical tilt grain boundary in NiAl. The simulations were carried out using molecular statics and embedded atom (EAM) potentials. The cracks are stabilized near a Griffith condition involving the cohesive energy of the grain boundary. The atomistic configurations of the tip region are different in the presence of the high angle grain boundary than in the bulk. Three different configurations of the grain boundary were studied corresponding to different local compositions. It was found that in ordered NiAl, cracks along symmetrical tilt boundaries show a more brittle behavior for Al rich boundaries than for Ni-rich boundaries. Lattice trapping effects in grain boundary fracture were found to be more significant than in the bulk.

Atomistic Simulations of [001] Symmetric Tilt Boundaries in Ni3Al

1986 ◽  
Vol 81 ◽  
Author(s):  
S. P. Chen ◽  
A. F. Voter ◽  
D. J. Srolovitz
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Simulation Study ◽  
Atomistic Simulation ◽  
Atomistic Simulations ◽  
Boundary Composition ◽  
Symmetric Tilt ◽  
Tilt Boundaries ◽  
Cohesive Energies

AbstractWe report a systematic atomistic simulation study of [001] symmetric tilt grain boundaries (GB) in Ni3Al, Ni, and Al. We found that the grain boundary energies and cohesive energies of Ni3Al and pure fcc Ni are approximately thesame. Grain boundary energies aid cohesive energies in Ni3Al depends stronglyon the grain boundary composition. The Al-rich boundaries have highest grain boundary energies and lowest cohesive energies. This offers an explanation for the stoichiometric effect on the boron ductilization

scholarly journals Superlubric polycrystalline graphene interfaces

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiang Gao ◽  
Wengen Ouyang ◽  
Michael Urbakh ◽  
Oded Hod
Keyword(s):  
Grain Boundary ◽  
Large Scale ◽  
Normal Load ◽  
Underlying Mechanism ◽  
Atomistic Simulations ◽  
Dissipated Energy ◽  
Frictional Properties ◽  
Dynamics Simulations ◽  
Two State Model ◽  
Nonmonotonic Behavior

AbstractThe effects of corrugated grain boundaries on the frictional properties of extended planar graphitic contacts incorporating a polycrystalline surface are investigated via molecular dynamics simulations. The kinetic friction is found to be dominated by shear induced buckling and unbuckling of corrugated grain boundary dislocations, leading to a nonmonotonic behavior of the friction with normal load and temperature. The underlying mechanism involves two effects, where an increase of dislocation buckling probability competes with a decrease of the dissipated energy per buckling event. These effects are well captured by a phenomenological two-state model, that allows for characterizing the tribological properties of any large-scale polycrystalline layered interface, while circumventing the need for demanding atomistic simulations. The resulting negative differential friction coefficients obtained in the high-load regime can reduce the expected linear scaling of grain-boundary friction with surface area and restore structural superlubricity at increasing length-scales.

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