Harnessing atomistic simulations to quantify activation parameters for dislocation nucleation from a grain boundary in Nickel

2020 ◽  
Vol 384 (20) ◽  
pp. 126501 ◽  
Author(s):  
S. Chandra ◽  
M.K. Samal ◽  
V.M. Chavan
Keyword(s):  
Grain Boundary ◽  
Activation Parameters ◽  
Dislocation Nucleation ◽  
Atomistic Simulations

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.

Nanometer Scale Mechanical Behavior of Grain Boundaries

2011 ◽  
Vol 1297 ◽  
Author(s):  
Chien-Kai Wang ◽  
Huck Beng Chew ◽  
Kyung-Suk Kim
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Virtual Work ◽  
Potential Interaction ◽  
Dislocation Nucleation ◽  
Nanometer Scale ◽  
Nonlinear Field ◽  
Boundary Slip ◽  
Nucleation Sites ◽  
Eam Potential

ABSTRACTA nonlinear field projection method has been developed to study nanometer scale mechanical properties of grain boundaries in nanocrystalline FCC metals. The nonlinear field projection is based on the principle of virtual work, for virtual variations of atomic positions in equilibrium through nonlocal interatomic interactions such as EAM potential interaction, to get field-projected subatomic-resolution traction distributions on various grain boundaries. The analyses show that the field projected traction produces periodic concentrated compression sites on the grain boundary, which act as crack trapping or dislocation nucleation sites. The field projection was also used to assess the nanometer scale failure processes of Cu Σ5 grain boundaries doped with Pb. It was revealed that the Pb dopants prevented the emission of dislocations by grain boundary slip and embrittles the grain boundary.

Interaction Between Lattice Dislocations and Grain Boundaries In Ordered Compounds

1990 ◽  
Vol 213 ◽  
Author(s):  
B.J. Pestman ◽  
J. Th. M. De Hosson ◽  
V. Vitek ◽  
F.W. Schapink
Keyword(s):  
Shear Stress ◽  
Grain Boundary ◽  
Grain Boundaries ◽  
Partial Dislocation ◽  
Atomistic Simulations ◽  
Many Body ◽  
Shockley Partial Dislocation ◽  
Screw Dislocations ◽  
Applied Shear Stress ◽  
Tilt Boundaries

ABSTRACTThe interaction of 1/2<1 1 0> screw dislocations with symmetric [1 1 0] tilt boundaries was investigated by atomistic simulations using many-body potentials representing ordered compounds. The calculations were performed with and without an applied shear stress. The observations were: absorption into the grain boundary, attraction of a lattice Shockley partial dislocation towards the grain boundary and transmission through the grain boundary under the influence of a shear stress. It was found that the interaction in ordered compounds shows similarities to the interaction in fcc.

Length Scale Effects in Materials Deformation of Nano and Microscale Au Structures

2009 ◽  
Author(s):  
Jie Lian ◽  
Junlan Wang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Size Effect ◽  
Sample Size ◽  
Atomistic Simulation ◽  
Scale Effects ◽  
Elastic Recovery ◽  
Boundary Effect ◽  
Dislocation Nucleation ◽  
Atomistic Simulations

In this study, intrinsic size effect — strong size dependence of mechanical properties — in materials deformation was investigated by performing atomistic simulation of compression on Au (114) pyramids. Sample boundary effect — inaccurate measurement of mechanical properties when sample size is comparable to the indent size — in nanoindentation was also investigated by performing experiments and atomistic simulations of nanoindentation into nano- and micro-scale Au pillars and bulk Au (001) surfaces. For intrinsic size effect, dislocation nucleation and motions that contribute to size effect were analyzed for studying the materials deformation mechanisms. For sample boundary effect, in both experiments and atomistic simulation, the elastic modulus decreases with increasing indent size over sample size ratio. Significantly different dislocation motions contribute to the lower value of the elastic modulus measured in the pillar indentation. The presence of the free surface would allow the dislocations to annihilate, causing a higher elastic recovery during the unloading of pillar indentation.

Atomistic simulations of grain boundary energies in austenitic steel

2019 ◽  
Vol 54 (7) ◽  
pp. 5570-5583 ◽  
Author(s):  
Sutatch Ratanaphan ◽  
Rajchawit Sarochawikasit ◽  
Noppadol Kumanuvong ◽  
Sho Hayakawa ◽  
Hossein Beladi ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Austenitic Steel ◽  
Atomistic Simulations

Extracting grain boundary motion in Cu–Al alloy from atomistic simulations

2020 ◽  
Vol 35 (20) ◽  
pp. 2701-2708
Author(s):  
Xiaobao Li ◽  
Hanlin Sun ◽  
Yuxue Pu ◽  
Changwen Mi
Keyword(s):  
Grain Boundary ◽  
Atomistic Simulations ◽  
Al Alloy ◽  
Boundary Motion ◽  
Grain Boundary Motion

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