The Dislocation Bias

Wolfer, W.G.

doi:10.1007/s10820-007-9051-3

Cited by 72 publications

(31 citation statements)

References 27 publications

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“…We note that the relaxation volume for a single tungsten SIA is around 1.7 Ω 0 , but for a large loop containing N interstitials the relaxation volume drops to NΩ 0 , in agreement with elasticity analysis [7,31]. Defect dipole tensors for the full cascades are given in table 6. We conclude that the relaxation volume of a cascade scales with the number of Frenkel pairs, with the DND potential giving…”

Section: Dipole Tensor For Defects Generated By a Collision Cascadesupporting

confidence: 79%

“…These stresses and strains have a microscopic origin and stem from the fact that radiation defects have substantial elastic relaxation volumes [6,7], which give rise to strong local deformation of the lattice. For example, the elastic relaxation volume of a self-interstitial atom defect in tungsten, predicted by density functional theory, is Ω rel = 1.67Ω 0 , where Ω 0 is the volume of an atom, whereas the relaxation volume of a vacancy is Ω rel = −0.37Ω 0 , see e.g.…”

Section: Introductionmentioning

confidence: 99%

“…There is extensive literature on the dynamics of accumulation of defects in microstructure and particularly on the evaluation of dislocation bias factors [6,[12][13][14][15][16][17], which are then used as input parameters for meanfield rate theory models describing the dynamics of growth of voids in materials exposed to irradiation [9][10][11]18]. These mean-field models do not require, and do not evaluate, the macroscopic stresses and strains resulting from the accumulation of defects.…”

Section: Introductionmentioning

confidence: 99%

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A multi-scale model for stresses, strains and swelling of reactor components under irradiation

et al. 2018

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Predicting strains, stresses and swelling in nuclear power plant components exposed to irradiation directly from the observed or computed defect and dislocation microstructure is a fundamental problem of fusion power plant design that has so far eluded a practical solution. We develop a model, free from parameters not accessible to direct evaluation or observation, that is able to provide estimates for irradiation-induced stresses and strains on a macroscopic scale, using information about the distribution of radiation defects produced by high-energy neutrons in the microstructure of materials. The model exploits the fact that elasticity equations involve no characteristic spatial scale, and hence admit a mathematical treatment that is an extension to that developed for the evaluation of elastic fields of defects on the nanoscale. In the analysis given below we use, as input, the radiation defect structure data derived from ab initio density functional calculations and large-scale molecular dynamics simulations of high-energy collision cascades. We show that strains, stresses and swelling can be evaluated using either integral equations, where the source function is given by the density of relaxation volumes of defects, or they can be computed from heterogeneous partial differential equations for the components of the stress tensor, where the density of body forces is proportional to the gradient of the density of relaxation volumes of defects. We perform a case study where strains and stresses are evaluated analytically and exactly, and develop a general finite element method implementation of the method, applicable to a broad range of predictive simulations of strains and stresses induced by irradiation in materials and components of any geometry in fission or fusion nuclear power plants.

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Section: Dipole Tensor For Defects Generated By a Collision Cascadesupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A multi-scale model for stresses, strains and swelling of reactor components under irradiation

et al. 2018

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“…Rate theory equations assume that defect densities are spatially homogeneous [8,9], or that they vary slowly as functions of spatial coordinates [10]. Elastic interactions are included in rate theory through the use of effective parameters, called bias factors [6,11,12]. The second approach 30 is to use kinetic Monte Carlo (kMC) simulations where defects are treated as mobile objects undergoing stochastic motion [13,14].…”

mentioning

confidence: 99%

Elastic interactions between nano-scale defects in irradiated materials

Dudarev

2017

Acta Materialia

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Closed form expressions are derived for the energy of elastic interaction between dislocation loops, and between dislocation loops and vacancy clusters, to enable simulations of elastically biased microstructural evolution of irradiated materials. The derivations assume the defects are separated by distances greater than their size. The resulting expressions are well suited for real-space simulations of microstructural evolution involving thousands of elastically interacting defects in 3D. They play a similar role to interatomic potentials in molecular dynamics simulations.

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“…Here, we introduce a new parametrization of the image interaction and a numerical quadrature scheme that gives accurate bias factors for the diffusion of point defects to spherical cavities in an isotropic elastic medium. The complementary dislocation bias factor is discussed in separate paper [4]. Ultimately, the long-range interaction can be fit with greater numerical accuracy than the environmental, material, or defect properties are known from experiments, while the quadrature scheme ensures comparable numerical precision for the dimensionless mean field bias factor.…”

Section: Introductionmentioning

confidence: 99%