scholarly journals Effect of dislocation configuration on Ag segregation in subgrain boundary of a Mg-Ag alloy

2021 ◽  
Vol 191 ◽  
pp. 219-224 ◽  
Author(s):  
Lirong Xiao ◽  
Xuefei Chen ◽  
Kang Wei ◽  
Yi Liu ◽  
Dongdi Yin ◽  
...  
Keyword(s):  
Subgrain Boundary ◽  
Dislocation Configuration

scholarly journals Driving forces on dislocations: finite element analysis in the context of the non-singular dislocation theory

2021 ◽  
Author(s):  
Xiandong Zhou ◽  
Christoph Reimuth ◽  
Peter Stein ◽  
Bai-Xiang Xu
Keyword(s):  
Finite Element ◽  
Dislocation Loop ◽  
Driving Force ◽  
Complex Geometry ◽  
Driving Forces ◽  
Singular Solutions ◽  
Dislocation Model ◽  
Configurational Force ◽  
Element Analysis ◽  
Dislocation Configuration

AbstractThis work presents a regularized eigenstrain formulation around the slip plane of dislocations and the resultant non-singular solutions for various dislocation configurations. Moreover, we derive the generalized Eshelby stress tensor of the configurational force theory in the context of the proposed dislocation model. Based on the non-singular finite element solutions and the generalized configurational force formulation, we calculate the driving force on dislocations of various configurations, including single edge/screw dislocation, dislocation loop, interaction between a vacancy dislocation loop and an edge dislocation, as well as a dislocation cluster. The non-singular solutions and the driving force results are well benchmarked for different cases. The proposed formulation and the numerical scheme can be applied to any general dislocation configuration with complex geometry and loading conditions.

Periodic dislocation configuration analysis by lattice distortion evaluation: micromechanical approach and X-ray diffraction line broadening

2004 ◽  
Vol 37 (2) ◽  
pp. 270-278 ◽  
Author(s):  
H. Bougrab ◽  
K. Inal ◽  
H. Sabar ◽  
M. Berveiller
Keyword(s):  
Dislocation Density ◽  
Fourier Coefficients ◽  
Lattice Distortion ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Range Interaction ◽  
Dislocation Configuration ◽  
Micromechanical Approach ◽  
Contrast Factor ◽  
Edge Dislocations

This work concerns dislocation microstructure analysis in order to assess stored elastic energy using Fourier coefficients of diffraction lines. These coefficients are related to the lattice distortion heterogeneity evaluated using a micromechanical approach. The lattice distortion formulation is based on dislocation density and Green's function tensors. The first tensor, which is a state quantity, characterizes the distortion incompatibility, while the second one characterizes the interaction phenomena between spatial positions. The proposed approach considers a given dislocation configuration in order to calculate the exact associated fields in a deterministic way. Periodic dislocation distributions were examined and the lattice distortion was calculated as a function of the distanceHbetween two successive dislocations (dislocation density). A short-range interaction effect was found for two values:H= 50 and 100 Å. Then Fourier coefficients of {h00}, {hhh} and {hkl} diffraction lines were estimated. It was observed that the sensitivity of the Fourier coefficients toHdepends strongly on the choice of the diffraction vector. Since the dislocation configurations were crystallographically defined, the contrast factor is included directly in our approach. For the considered slip system, it is shown that the screw periodical distribution has a higher Fourier coefficient variation than the periodical edge dislocations.

A study of relationship between dislocation configuration of nanocrack and brittle-ductile mode of fracture: Atomistic modeling

2020 ◽  
Vol 173 ◽  
pp. 109413 ◽  
Author(s):  
Li-Lin Huang ◽  
Ying-Jun Gao ◽  
Qian-Qian Deng ◽  
Zhe-Yuan Liu ◽  
Zhi-Rong Luo ◽  
...  
Keyword(s):  
Atomistic Modeling ◽  
Dislocation Configuration ◽  
Ductile Mode

X-Ray Diffraction Analysis of Simultaneous Changes in Stress and Dislocation Densities in Thin Films

1995 ◽  
Vol 39 ◽  
pp. 195-210
Author(s):  
A. C. Vermeulen ◽  
R. Delhez ◽  
Th.H. de Keijser ◽  
E. J. Mittemeijer
Keyword(s):  
Room Temperature ◽  
X Ray Diffraction ◽  
Parallel Edge ◽  
Polycrystalline Specimen ◽  
Dislocation Configuration ◽  
Burgers Vector ◽  
X Ray ◽  
Dislocation Densities ◽  
Direction Dependence ◽  
Dislocation Annihilation

A method has heen developed to determine the dislocation configuration in a polycrystalline specimen from the direction dependence of line broadening. The method is based on an analytical expression for the integral breadth due to microstrain from sets of parallel edge and/or screw dislocations on the specific slip systems. Analysis of the x-ray-diffraction measurements obtained from poly crystalline aluminium layers, deposited onto silicon wafers and subsequently annealed and cooled to room temperature, shows unequal densities and unequal changes of densities of dislocations with the Burgers vector parallel and with the Burgers vector inclined with respect to the surface of the layer. Stress relaxation and dislocation annihilation occur at room temperature. A model was developed to describe the dependency of the decrease of macrostress on the decrease of the dislocation density.

X-ray topographic studies of dislocations in iron-silicon alloy single crystals

1965 ◽  
Vol 285 (1401) ◽  
pp. 297-311 ◽  
Keyword(s):  
Single Crystals ◽  
Bulk Material ◽  
Spatial Arrangement ◽  
Atomic Weight ◽  
Thin Plates ◽  
Etch Pits ◽  
Etching Technique ◽  
Dislocation Configuration ◽  
X Ray ◽  
Dislocation Etching

Thin plates cut from melt-grown single crystals of iron +3.5% silicon were examined by an X-ray transmission topographic method and the spatial arrangement of individual dislocations and of dislocation arrays was investigated. The directions (including the sense in some cases) of dislocation Burgers vectors were identified. It was confirmed that Burgers vectors lie along <111>. Reactions such as ½[1̄11] + ½[111̄] = [010] were not observed among the individually resolved dislocations. The minimum separation of dislocations for easy individual resolution was 3 μ m with Co Kα radiation and 5 μ m with Ag Kα . It was demonstrated that a one-to-one correspondence exists between dislocation outcrops and the etch pits produced by the dislocation-etching technique of Šesták (1959). The experiments showed that transmission X-ray topography when applied to metals of moderately heavy atomic weight can give a clear picture of the dislocation configuration in specimens sufficiently thick to be fully representative of the bulk material.

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