Fast, vacancy-free climb of prismatic dislocation loops in bcc metals

Swinburne, Thomas D.; Arakawa, Kazuto; Mori, Hirotarô; Yasuda, Hidehiro; Isshiki, Minoru; Mimura, Kouji; Uchikoshi, Masahito; Dudarev, S. L.

doi:10.1038/srep30596

Cited by 61 publications

(60 citation statements)

References 35 publications

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“…These experimental results were explained later on based on the mechanism of motion and coalescence of dislocation loops by pipe diffusion, which is called the self-climb mechanism [9]. More details of the coalescence have been observed in the later experiments [10,11,12]. It was demonstrated in Ref.…”

Section: Introductionmentioning

confidence: 84%

“…These authors showed that two nearby prismatic loops of order 10nm in iron at 750K coalesce after a time of order 10s in both results of their atomistic self-climb model and experiment, and it is six orders of magnitude faster than the time predicted by using bulk vacancy diffusion assisted climb. Such self-climb (conservative climb) motion of dislocations plays critical roles in the properties of irradiated materials and has been an active research topic ever since it was first observed in 1960's [2,6,7,8,9,10,11,3,5,12,13,14,15].…”

Section: Introductionmentioning

confidence: 99%

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Dislocation dynamics formulation for self-climb of dislocation loops by vacancy pipe diffusion

Niu

Xiang

2019

International Journal of Plasticity

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It has been shown in experiments that self-climb of prismatic dislocation loops by pipe diffusion plays important roles in their dynamical behaviors, e.g., coarsening of prismatic loops upon annealing, as well as the physical and mechanical properties of materials with irradiation. In this paper, we show that this dislocation dynamics self-climb formulation that we derived in Ref.[1] is able to quantitatively describe the properties of self-climb of prismatic loops that were observed in experiments and atomistic simulations. This dislocation dynamics formulation applies to self-climb by pipe diffusion for any configurations of dislocations, and is able to recover the available models in the literature for rigid self-climb motion of small prismatic loops. We also present DDD implementation method of this selfclimb formulation. Simulations performed show evolution, translation and coalescence of prismatic loops as well as prismatic loops driven by an edge dislocation by self-climb motion and the elastic interaction between them. These results are in excellent agreement with available experimental and atomistic results. We have also performed systematic analyses of the behaviors of a prismatic loop under the elastic interaction with an infinite, straight edge dislocation by motions of self-climb and glide.

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Section: Introductionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Dislocation dynamics formulation for self-climb of dislocation loops by vacancy pipe diffusion

Niu

Xiang

2019

International Journal of Plasticity

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“…where n(r, E) is the spatial density of cascades with energy E and Ω rel (E) is the relaxation volume of defects produced in a cascade initiated by a recoil atom of energy E. In practice, this function can be computed using neutron transport calculations for a realistic reactor geometry [63,64] followed by the evaluation of local spectra of primary knock-on atoms [65] and the treatment of the subsequent evolution of microstructure, including modelling dislocation climb [66], self-climb [67], and the formation of a network of dislocations, voids and gas bubbles.…”

Section: Dipole Tensor For Defects Generated By a Collision Cascadementioning

confidence: 99%

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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“…[30]). This kind of process, known as coalescence, is common for defect coarsening in metals [33][34][35]. However, our work appears to be the first evidence of such a mechanism for ED growth in solid semiconductors.…”

Section: In Ref [30])mentioning

confidence: 45%

Ultrafast Generation of Unconventional{001}Loops in Si

et al. 2017

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Ultrafast laser annealing of ion implanted Si has led to thermodynamically unexpected large {001} self-interstitial loops, and the failure of Ostwald ripening models for describing self-interstitial cluster growth. We have carried out molecular dynamics simulations in combination with focused experiments in order to demonstrate that at temperatures close to the melting point, self-interstitial rich Si is driven into dense liquidlike droplets that are highly mobile within the solid crystalline Si matrix. These liquid droplets grow by a coalescence mechanism and eventually transform into {001} loops through a liquid-to-solid phase transition in the nanosecond time scale.

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Fast, vacancy-free climb of prismatic dislocation loops in bcc metals

Cited by 61 publications

References 35 publications

Dislocation dynamics formulation for self-climb of dislocation loops by vacancy pipe diffusion

Dislocation dynamics formulation for self-climb of dislocation loops by vacancy pipe diffusion

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

Ultrafast Generation of Unconventional{001}Loops in Si

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