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.

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 symmetrical tilt grain boundary on the compatibility between copper and liquid lithium: Atomistic simulations

2020 ◽  
Vol 835 ◽  
pp. 155212
Author(s):  
Chao Xu ◽  
Jun Wei ◽  
Bowen Huang ◽  
Xiancai Meng ◽  
Shifang Xiao ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Liquid Lithium ◽  
Atomistic Simulations ◽  
Symmetrical Tilt ◽  
Tilt Grain Boundary

Defects in the Structure of Σ=27 Tilt Grain-Boundaries in Ge.

1990 ◽  
Vol 209 ◽  
Author(s):  
Stuart Mckernan ◽  
C. Barry Carter ◽  
Zvi Elgat
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Screw Dislocation ◽  
Structural Unit ◽  
Boundary Plane ◽  
High Angle ◽  
Structural Units ◽  
Short Segment ◽  
Tilt Boundaries ◽  
Tilt Grain Boundary

ABSTRACTGeneral high-angle tilt grain-boundaries may be described by an arrangement of repeating structural units. A particular defect in the normal arrangement of structural units in a Σ=27 <110> tilt grain-boundary in Ge is reported.The defect is characterized by a short segment of (111) facet at the interface, and is associated with a screw dislocation in the boundary plane. This defect accommodates a slight misorientation of the boundary away from the perfect tilt configuration, andmay represent a type of structural unit present in other tilt boundaries containing a small twist component.

Structures of a Σ = 9, [110]/{221} symmetrical tilt grain boundary in SrTiO3

2011 ◽  
Vol 46 (12) ◽  
pp. 4162-4168 ◽  
Author(s):  
T. Mitsuma ◽  
T. Tohei ◽  
N. Shibata ◽  
T. Mizoguchi ◽  
T. Yamamoto ◽  
...  
Keyword(s):  
Grain Boundary ◽  
Symmetrical Tilt ◽  
Tilt Grain Boundary

Atomic Mechanisms of Grain Boundary Motion

2005 ◽  
Vol 502 ◽  
pp. 157-162 ◽  
Author(s):  
A. Suzuki ◽  
Yuri M. Mishin
Keyword(s):  
Molecular Dynamics ◽  
Grain Boundary ◽  
Geometric Model ◽  
Lattice Rotation ◽  
Shear Stresses ◽  
Translation Rate ◽  
Embedded Atom ◽  
Local Lattice ◽  
Symmetrical Tilt ◽  
Grain Boundary Motion

We present results of atomistic computer simulations of spontaneous and stress-induced grain boundary (GB) migration in copper. Several symmetrical tilt GBs have been studied using the embedded-atom method and molecular dynamics. The GBs are observed to spontaneously migrate in a random manner. This spontaneous GB motion is always accompanied by relative translations of the grains parallel to the GB plane. Furthermore, external shear stresses applied parallel to the GB and normal to the tilt axis induce GB migration. Strong coupling is observed between the normal GB velocity vn and the grain translation rate v||. The mechanism of GB motion is established to be local lattice rotation within the GB core that does not involve any GB diffusion or sliding. The coupling constant between vn and v|| predicted within a simple geometric model accurately matches the molecular dynamics observations.

Microstructures of a-axis oriented YBCO films made by hybrid plasma sputtering

1995 ◽  
Vol 10 (4) ◽  
pp. 803-809 ◽  
Author(s):  
W. Ito ◽  
A. Oishi ◽  
S. Mahajan ◽  
Y. Yoshida ◽  
T. Morishita
Keyword(s):  
Electron Microscopy ◽  
Grain Boundary ◽  
Anisotropic Growth ◽  
Plan View ◽  
Plasma Sputtering ◽  
Transmission Electron ◽  
Hybrid Plasma ◽  
Tilt Boundaries ◽  
Symmetrical Tilt ◽  
Twist Boundaries

Microstructures of a-axis oriented YBa2Cu3O7−x films made by newly developed de 100 MHz hybrid plasma sputtering were investigated using transmission electron microscopy (TEM). The films deposited on (110) NdGaO3 and (100) SrTiO3 substrates were found to grow in a perfect epitaxial fashion and with clear interface. The plan view of the TEM image showed that both films were comprised of two kinds of grains having the c axis aligning along two perpendicular directions in the plane with equal probability. The structures of the grain boundary, however, were found to be very different for the two films from the plan views. The film on NdGaO3 showed a lot of twist boundaries, while the film on SrTiO3 consisted of many symmetrical tilt boundaries and basal-plane-faced tilt boundaries. The type of grain boundary is determined by the anisotropic growth rates of the film between c direction and a-b direction.

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