scholarly journals Crack Length Effect on the Fracture Behavior of Single-Crystals and Bi-Crystals of Aluminum

Nanomaterials ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 2783
Author(s):  
Wilmer Velilla-Díaz ◽  
Habib R. Zambrano
Keyword(s):  
Grain Boundary ◽  
Crack Length ◽  
Single Crystals ◽  
Fracture Resistance ◽  
Fracture Behavior ◽  
Length Effect ◽  
Atomistic Models ◽  
Novel Approaches ◽  
Mechanics Concepts ◽  
Dynamics Simulations

Molecular dynamics simulations of cracked nanocrystals of aluminum were performed in order to investigate the crack length and grain boundary effects. Atomistic models of single-crystals and bi-crystals were built considering 11 different crack lengths. Novel approaches based on fracture mechanics concepts were proposed to predict the crack length effect on single-crystals and bi-crystals. The results showed that the effect of the grain boundary on the fracture resistance was beneficial increasing the fracture toughness almost four times for bi-crystals.

Simulation of Fracture Behavior in the Microstructure of Ceramic Tool Materials

2012 ◽  
Vol 457-458 ◽  
pp. 89-92
Author(s):  
Ting Ting Zhou ◽  
Chuan Zhen Huang ◽  
Han Lian Liu ◽  
Jun Wang ◽  
Bin Zou ◽  
...  
Keyword(s):  
Finite Element ◽  
Grain Boundary ◽  
Fracture Resistance ◽  
Fracture Behavior ◽  
Single Phase ◽  
Voronoi Tessellation ◽  
Element Model ◽  
Cohesive Element ◽  
Ceramic Tool ◽  
Tool Materials

In the paper, the Voronoi tessellation model is used to represent the microstructure of ceramic tool materials. And a finite element model based on cohesive element method has been developed to investigate the fracture behavior of the microstructure. The influences of mesh densities and cohesive parameters on the cracking patterns have been discussed. It is found that the enhancement of the grain boundary strength is beneficial for raising the fracture resistance of single-phase ceramic tool materials.

Vertex Dynamics Simulations of Orientation Dependent Recovery in Deformed Aluminium Single Crystals

2011 ◽  
Vol 702-703 ◽  
pp. 639-642
Author(s):  
Adhish Majumdar ◽  
Claire Maurice ◽  
Julian H. Driver
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Single Crystals ◽  
Dynamics Simulation ◽  
Boundary Misorientation ◽  
Annealing Behaviour ◽  
The Common ◽  
Dynamics Simulations ◽  
Orientation Dependency ◽  
Good Agreement

A 2-dimensional vertex dynamics simulation is applied to the annealing behaviour of deformed Aluminium single crystals having different orientations. It is observed in experiments that deformed single crystals of different orientations - typically the common rolling textures like Goss (110)[001], Brass (110)[1-12], Cube (001)[100] – exhibit remarkably different rates of recovery. It is suggested that this difference arises from the deformation microstructures, with sub-grain boundaries of various misorientation values. The sub-grain boundary mobilities and energies, being strong functions of the boundary misorientation, thus affect the recovery rates. This effect is illustrated using vertex dynamics simulation on the same orientations and schematic deformation substructures as above. Good agreement is obtained for the orientation dependency of recovery.

scholarly journals Elucidating the Onset of Plasticity in Sliding Contacts Using Differential Computational Orientation Tomography

2021 ◽  
Vol 69 (3) ◽  
Author(s):  
S. J. Eder ◽  
P. G. Grützmacher ◽  
M. Rodríguez Ripoll ◽  
J. F. Belak
Keyword(s):  
Grain Boundary ◽  
Large Scale ◽  
Surface Deformation ◽  
Boundary Migration ◽  
Material Design ◽  
Lattice Rotation ◽  
Time Resolved ◽  
Near Surface ◽  
Color Saturation ◽  
Dynamics Simulations

Abstract Depending on the mechanical and thermal energy introduced to a dry sliding interface, the near-surface regions of the mated bodies may undergo plastic deformation. In this work, we use large-scale molecular dynamics simulations to generate “differential computational orientation tomographs” (dCOT) and thus highlight changes to the microstructure near tribological FCC alloy surfaces, allowing us to detect subtle differences in lattice orientation and small distances in grain boundary migration. The analysis approach compares computationally generated orientation tomographs with their undeformed counterparts via a simple image analysis filter. We use our visualization method to discuss the acting microstructural mechanisms in a load- and time-resolved fashion, focusing on sliding conditions that lead to twinning, partial lattice rotation, and grain boundary-dominated processes. Extracting and laterally averaging the color saturation value of the generated tomographs allows us to produce quantitative time- and depth-resolved maps that give a good overview of the progress and severity of near-surface deformation. Corresponding maps of the lateral standard deviation in the color saturation show evidence of homogenization processes occurring in the tribologically loaded microstructure, frequently leading to the formation of a well-defined separation between deformed and undeformed regions. When integrated into a computational materials engineering framework, our approach could help optimize material design for tribological and other deformation problems. Graphic Abstract .

Inspection Of Recombination Active Defects For Sige And Solar Cells

1996 ◽  
Vol 442 ◽  
Author(s):  
O.V. Astafiev ◽  
V.P. Kalinushkin ◽  
N.V. Abrosimov
Keyword(s):  
Solar Cells ◽  
Solar Cell ◽  
Light Scattering ◽  
Grain Boundary ◽  
Single Crystals ◽  
Defect Structure ◽  
Scattering Method ◽  
Recombination Activity ◽  
Cell Production ◽  
Materials Used

AbstractMapping Low Angle Light Scattering method (MLALS) is proposed to study defect structure in materials used for solar cell production. Several types of defects are observed in Czochralski Si1−xGex (0.022<x<0.047) single crystals. Recombination activity of these defects is investigated. The possibility of contactless visualisation of grain boundary recombination in polysilicon is also demonstrated.

scholarly journals Ultrafast calculation of diffuse scattering from atomistic models

2019 ◽  
Vol 75 (1) ◽  
pp. 14-24 ◽  
Author(s):  
Joseph A. M. Paddison
Keyword(s):  
Diffuse Scattering ◽  
Large Data ◽  
Large Data Sets ◽  
Scattering Data ◽  
Frequency Noise ◽  
Data Sets ◽  
Fast Method ◽  
Crystalline Materials ◽  
Atomistic Models ◽  
Dynamics Simulations

Diffuse scattering is a rich source of information about disorder in crystalline materials, which can be modelled using atomistic techniques such as Monte Carlo and molecular dynamics simulations. Modern X-ray and neutron scattering instruments can rapidly measure large volumes of diffuse-scattering data. Unfortunately, current algorithms for atomistic diffuse-scattering calculations are too slow to model large data sets completely, because the fast Fourier transform (FFT) algorithm has long been considered unsuitable for such calculations [Butler & Welberry (1992). J. Appl. Cryst. 25, 391–399]. Here, a new approach is presented for ultrafast calculation of atomistic diffuse-scattering patterns. It is shown that the FFT can actually be used to perform such calculations rapidly, and that a fast method based on sampling theory can be used to reduce high-frequency noise in the calculations. These algorithms are benchmarked using realistic examples of compositional, magnetic and displacive disorder. They accelerate the calculations by a factor of at least 102, making refinement of atomistic models to large diffuse-scattering volumes practical.

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