Core Structure And Mobility Of a <101] Dislocations In L10 TiAl

1994 ◽  
Vol 364 ◽  
Author(s):  
S. Rao ◽  
C. Woodward ◽  
J. Simmons ◽  
D. Dimiduk
Keyword(s):  
Elastic Properties ◽  
Friction Stress ◽  
Core Structure ◽  
Line Orientation ◽  
Embedded Atom Method ◽  
Shockley Partial ◽  
Embedded Atom ◽  
The Ideal

AbstractAn empirical atomistic potential, fit to the structural and elastic properties of L10 TiAl within the embedded atom method (EAM), is used to simulate the mobility of two possible planar forms of a<101] dislocations in a model L10 compound. The two configurations examined were: the planar SISF-APB-CSF coupled (P core) and the decomposed 1/2<110]-SISF-SESF coupled (D core). Six different line orientations are considered for the P core: 0° (screw), 30°, 60°, 90° (edge), 120° and 150°. The ‘ideal’ friction stress at 0°K of a<101] dislocations in the P form is found to be a function of line orientation, with the close packed line directions, <101] (screw) and <110] (60°), having friction stresses ranging from 0.001–0.002μ. Previously calculated results on the friction stress of a/2<110] dislocations, using an identical potential are consistently higher than the friction stress of a<101] dislocations. Simulations of the interaction of glide strains with the D core for the 60° (line directions < 110]) and 120° (line directions <011]) orientations show that the Shockley partial trailing the SESF in the D core is strongly pinned. The dislocation moves by extension of SESF when glide stresses are applied with SESF as the trailing fault.

Structure and Elastic Properties of Ni/Cu and Ni/Au Multilayers

1992 ◽  
Vol 291 ◽  
Author(s):  
Ademola Taiwo ◽  
Hong Yan ◽  
Gretchen Kalonji
Keyword(s):  
Phase Transformation ◽  
Elastic Properties ◽  
Embedded Atom Method ◽  
Interatomic Potentials ◽  
Multilayer Systems ◽  
Lattice Statics ◽  
Embedded Atom ◽  
Hcp Structure ◽  
Fcc Structure ◽  
Coherent Interfaces

ABSTRACTThe structure and elastic properties of Ni/Cu and Ni/Au multilayer systems are investigated as a function of the number of Ni monolayers built into the systems. We employed lattice statics simulations with the interatomic potentials described by the embedded-atom method. For the Ni/Cu systems, coherent interfaces and FCC structure are maintained, and no elastic anomaly is found. For the Ni/Au systems, when the Ni layers are thick enough, they undergo a strain-induced phase transformation from FCC to HCP structure. An enhancement of Young’s modulus of these systems is found to be associated with this structural change.

Stability of Hollow Nanospheres: A Molecular Dynamics Study

2007 ◽  
Vol 129 ◽  
pp. 125-130 ◽  
Author(s):  
Alexander V. Evteev ◽  
Elena V. Levchenko ◽  
Irina V. Belova ◽  
Graeme E. Murch
Keyword(s):  
Molecular Dynamics ◽  
Defect Formation ◽  
External Surface ◽  
Vacancy Concentration ◽  
Dynamics Simulation ◽  
Embedded Atom Method ◽  
Hollow Nanospheres ◽  
Shockley Partial ◽  
Embedded Atom ◽  
Partial Dislocations

Molecular dynamics simulation using the embedded-atom method is applied to study defect formation and distribution in a hollow Pd nanosphere. It is established that besides vacancies, which can nucleate on the inner or external surfaces, at the external surface, other defects (Shockley partial dislocations, twins and stacking faults) form due to its significant reconstruction by means of a/6〈112〉 shears of atomic rows. The density of the defects on the external surface grows with decreasing nanoshell size. It is demonstrated that Shockley partial dislocations can act as vehicles for the transfer of material from the external surface to the inner surface of the nanoshell thus leading to shrinking. It is shown that the vacancy concentration is higher near both surfaces than in the bulk of the nanoshell.

Atomistic Structure and Composition of a Ag/Ni Interphase Boundary

1990 ◽  
Vol 187 ◽  
Author(s):  
P. Gumbsch ◽  
M. S. Daw ◽  
S. M. Foiles ◽  
H. F. Fischmeister
Keyword(s):  
Interphase Boundary ◽  
Minimum Energy ◽  
Embedded Atom Method ◽  
Interface Plane ◽  
Misfit Dislocations ◽  
Abrupt Transition ◽  
Embedded Atom ◽  
Induced Stresses ◽  
Atomistic Structure ◽  
The Ideal

AbstractUsing the embedded atom method we atomistically model the compensation of the misfit induced stresses in a “cube on cube” oriented Ag/Ni bicrystal with (011) interface plane, in which zones of maximum misfit (misfit dislocations) run along the [100] and the [011] directions.The ideal interface corresponds to an abrupt transition between Ag and Ni. The interfacial enthalpy is found to be lowered by the introduction of vacancies on the Ni side (equivalently, vacancies are trapped on the Ni side of the boundary). Pursuing this perspective, we find that the interfacial enthalpy is lowered considerably by the removal of a complete line of Ni atoms along the [011] direction from the Ni side of the boundary. The minimum energy configuration consists of a Ni layer whose atomic density is reduced by 16% sandwiched between the ordinary Ni and Ag lattices.

Atomistic Simulation Study of Controlled Nanostructure Patterning

2003 ◽  
Vol 775 ◽  
Author(s):  
Byeongchan Lee ◽  
Kyeongjae Cho
Keyword(s):  
Diffusion Barrier ◽  
Atomistic Simulation ◽  
Degrees Of Freedom ◽  
Embedded Atom Method ◽  
Surface Kinetics ◽  
Bulk Properties ◽  
Embedded Atom ◽  
Kinetics Of ◽  
Dissociation Barrier ◽  
Strain Dependent

AbstractWe investigate the surface kinetics of Pt using the extended embedded-atom method, an extension of the embedded-atom method with additional degrees of freedom to include the nonbulk data from lower-coordinated systems as well as the bulk properties. The surface energies of the clean Pt (111) and Pt (100) surfaces are found to be 0.13 eV and 0.147 eV respectively, in excellent agreement with experiment. The Pt on Pt (111) adatom diffusion barrier is found to be 0.38 eV and predicted to be strongly strain-dependent, indicating that, in the compressive domain, adatoms are unstable and the diffusion barrier is lower; the nucleation occurs in the tensile domain. In addition, the dissociation barrier from the dimer configuration is found to be 0.82 eV. Therefore, we expect that atoms, once coalesced, are unlikely to dissociate into single adatoms. This essentially tells that by changing the applied strain, we can control the patterning of nanostructures on the metal surface.

Modified embedded-atom method potentials for the plasticity and fracture behaviors of unary fcc metals

2021 ◽  
Vol 103 (9) ◽  
Author(s):  
Zachary H. Aitken ◽  
Viacheslav Sorkin ◽  
Zhi Gen Yu ◽  
Shuai Chen ◽  
Zhaoxuan Wu ◽  
...  
Keyword(s):  
Embedded Atom Method ◽  
Fcc Metals ◽  
Embedded Atom ◽  
Fracture Behaviors ◽  
Modified Embedded Atom Method

scholarly journals Fabrication of Magnesium-Aluminum Composites under High-Pressure Torsion: Atomistic Simulation

2021 ◽  
Vol 11 (15) ◽  
pp. 6801
Author(s):  
Polina Viktorovna Polyakova ◽  
Julia Alexandrovna Pukhacheva ◽  
Stepan Aleksandrovich Shcherbinin ◽  
Julia Aidarovna Baimova ◽  
Radik Rafikovich Mulyukov
Keyword(s):  
Atomistic Simulation ◽  
High Pressure Torsion ◽  
Tensile Tests ◽  
Temperature Treatment ◽  
Embedded Atom Method ◽  
Interface Bonding ◽  
Embedded Atom ◽  
Interlayer Region ◽  
Kinetics Of ◽  
Loading Scheme

The aluminum–magnesium (Al–Mg) composite materials possess a large potential value in practical application due to their excellent properties. Molecular dynamics with the embedded atom method potentials is applied to study Al–Mg interface bonding during deformation-temperature treatment. The study of fabrication techniques to obtain composites with improved mechanical properties, and dynamics and kinetics of atom mixture are of high importance. The loading scheme used in the present work is the simplification of the scenario, experimentally observed previously to obtain Al–Cu and Al–Nb composites. It is shown that shear strain has a crucial role in the mixture process. The results indicated that the symmetrical atomic movement occurred in the Mg–Al interface during deformation. Tensile tests showed that fracture occurred in the Mg part of the final composite sample, which means that the interlayer region where the mixing of Mg, and Al atoms observed is much stronger than the pure Mg part.

scholarly journals An interatomic potential for saturated hydrocarbons based on the modified embedded-atom method

2014 ◽  
Vol 16 (13) ◽  
pp. 6233-6249 ◽  
Author(s):  
S. Nouranian ◽  
M. A. Tschopp ◽  
S. R. Gwaltney ◽  
M. I. Baskes ◽  
M. F. Horstemeyer
Keyword(s):  
Interatomic Potential ◽  
Embedded Atom Method ◽  
Computationally Efficient ◽  
Saturated Hydrocarbons ◽  
Embedded Atom ◽  
Modified Embedded Atom Method

Extension of the computationally efficient modified embedded-atom method to hydrocarbons and polymers.

Modified embedded-atom method interatomic potential for theFe−Cualloy system and cascade simulations on pure Fe andFe−Cualloys

2005 ◽  
Vol 71 (18) ◽  
Author(s):  
Byeong-Joo Lee ◽  
Brian D. Wirth ◽  
Jae-Hyeok Shim ◽  
Junhyun Kwon ◽  
Sang Chul Kwon ◽  
...  
Keyword(s):  
Interatomic Potential ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
Modified Embedded Atom Method

The Study of Defects in Metals Using High Resolution Transmission Electron Microscopy and Atomistic Calculations

1990 ◽  
Vol 183 ◽  
Author(s):  
M. J. Mills ◽  
M. S. Daw
Keyword(s):  
Grain Boundary ◽  
Good Description ◽  
Dislocation Core ◽  
Thin Foil ◽  
Core Structure ◽  
Embedded Atom ◽  
Pair Potentials ◽  
Transmission Electron ◽  
Atomistic Calculations ◽  
Stringent Test

AbstractThe coupling of HRTEM with atomistic calculations is described for the study of grain boundaries and dislocations in aluminum. HRTEM images of the Σ9 (221) [110] grain boundary are compared with molecular statics calculations using both the Embedded Atom Method (EAM) and two pair potentials. Comparison between observed and simulated images are shown to serve as a stringent test of the theoretical methods. Atomistic calculations can in turn provide threedimensional information about the defect structure. Using the EAM, it is also possible to account for the effects of thin foil geometries on the minimim energy configuration of defects. While these effects are found to be minimal for grain boundary structures, the influence of the thin-foil geometries on the core structure of the 60° dislocation in aluminum is discussed. These comparisons indicate that the EAM function provides a good description of grain boundary structures, but fails to reproduce the observed dislocation core structure due to a low predicted value of the intrinsic stacking fault energy (SFE) on the (111). In contrast, the pair potentials used in this study provide reasonable SFE values, but appear to be less accurate for the prediction of the Σ9 (221) [110] grain boundary structures.

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