Atomic Structure Calculations of the Interaction between Lattice Dislocations and Grain Boundaries

ABSTRACTThe interaction between screw dislocations and [1 1 0] symmetric tilt boundaries is investigated by atomistic calculations. In order to study the differences between fcc and ordered alloys and to study the effect of increasing ordering tendency, many-body potentials representing Cu, Cu3Au and Ni3Al were used. For the ordered alloys, the different possible ordering configurations of the boundaries that were studied are discussed.

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Interaction Between Lattice Dislocations and Grain Boundaries In Ordered Compounds

MRS Proceedings ◽

10.1557/proc-213-429 ◽

1990 ◽

Vol 213 ◽

Cited By ~ 1

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.

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Базовые элементы структуры границ зерен наклона. Часть 2. Оси разориентации [110] и [111]-=SUP=-*-=/SUP=-

Физика твердого тела ◽

10.21883/ftt.2021.01.50398.398 ◽

2021 ◽

Vol 63 (1) ◽

pp. 55

Author(s):

А.В. Векман ◽

Б.Ф. Демьянов

Keyword(s):

Grain Boundaries ◽

Atomic Structure ◽

Pair Potential ◽

Structural Vacancy ◽

Many Body ◽

Structural Units ◽

Symmetric Tilt ◽

Vacancy Model ◽

Body Potential ◽

Misorientation Angles

The computer simulation methods have been applied to calculate structure and energy of symmetric tilt grain boundaries (GB) with the misorientation axes [110] and [111]. The calculations have been carried out with the use of the structural-vacancy model. The study of the atomic structure has been carried out within the entire range of misorientation angles. The reverse density of coincidence sites in special grain boundaries has amounted Σ≤57. The calculations have been carried out with the use of the Morse pair potential and the Cleri-Rosato many-body potential. When calculated with different potentials, the dependence of GB energy on the misorientation angle has a similar form, and the atomic structure completely coincides. It has been shown that the structure of any GB with the misorientation axes [110] and [111] may be represented by a limited number of basic structural units. All found basic structural units defined as units of A, B, C and D types are based on the structures of special grain boundaries. Such special GBs shall be Σ3(111), Σ3(112), Σ11(113) and Σ9(114) for GBs with the misorientation axis [110], and as regarding GBs with the misorientation axis [111], such special GBs shall be Σ3(112), Σ7(123) and Σ13(134). Ranges of angles within which certain basic structural units are found have been defined.

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Many-body perturbation theory in atomic structure calculations

Physica Scripta ◽

10.1088/0031-8949/1993/t46/014 ◽

1993 ◽

Vol T46 ◽

pp. 102-109 ◽

Cited By ~ 5

Author(s):

Ann-Marie Mårtensson-Pendrill

Keyword(s):

Perturbation Theory ◽

Atomic Structure ◽

Many Body ◽

Many Body Perturbation Theory ◽

Atomic Structure Calculations ◽

Structure Calculations

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Towards B-Spline Atomic Structure Calculations

Atoms ◽

10.3390/atoms9030050 ◽

2021 ◽

Vol 9 (3) ◽

pp. 50

Author(s):

Charlotte Froese Fischer

Keyword(s):

Atomic Structure ◽

Bound States ◽

Virial Theorem ◽

B Spline ◽

B Splines ◽

Self Consistent ◽

History Of ◽

Consistent Method ◽

Atomic Structure Calculations ◽

Structure Calculations

The paper reviews the history of B-spline methods for atomic structure calculations for bound states. It highlights various aspects of the variational method, particularly with regard to the orthogonality requirements, the iterative self-consistent method, the eigenvalue problem, and the related sphf, dbsr-hf, and spmchf programs. B-splines facilitate the mapping of solutions from one grid to another. The following paper describes a two-stage approach where the goal of the first stage is to determine parameters of the problem, such as the range and approximate values of the orbitals, after which the level of accuracy is raised. Once convergence has been achieved the Virial Theorem, which is evaluated as a check for accuracy. For exact solutions, the V/T ratio for a non-relativistic calculation is −2.

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Atomic Structure and Property Correlation in Pulsed Laser Deposited High -Tc Films

MRS Proceedings ◽

10.1557/proc-526-281 ◽

1998 ◽

Vol 526 ◽

Author(s):

R. Kalyanaraman ◽

S. Oktyabrsky ◽

K. Jagannadham ◽

J. Narayan

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Grain Boundaries ◽

Atomic Structure ◽

Substrate Surface ◽

Pulsed Laser ◽

Structure And Property ◽

Transmission Electron ◽

Tilt Boundaries ◽

Z Contrast

AbstractThe atomic structure of grain boundaries in pulsed laser deposited YBCO/MgO thin films have been studied using transmission electron microscopy. The films have perfect texturing with YBCO(001)//MgO(001), giving rise to low-angle [001] tilt boundaries from the grains with the c-axis normal to substrate surface. Low angle grain boundaries have been found to be aligned preferentially along (100) and (110) interface planes. The energy of (110) boundary planes described by an alternating array of [100] and [010] dislocation is found to be comparable to the energy of a (100) boundary. The existence of these split dislocations is shown to further reduce the theoretical current densities of these boundaries indicating that (110) boundaries carry less current as compared to (100) boundaries of the same misorientation angle. Further, Z-contrast transmission electron microscopy of a 42° asymmetric high-angle grain boundary of YBCO shows evidence for the existence of boundary fragments and a reduced atomic density along the boundary plane

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