Interaction of dislocations with carbides in BCC Fe studied by molecular dynamics

Granberg, Fredric; Terentyev, D.; Nordlund, K.

doi:10.1016/j.jnucmat.2015.01.064

Cited by 21 publications

(11 citation statements)

References 35 publications

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“…A more realistic model for the stress field of the precipitate is possible with the Eshelby-solution for the spherical inclusion [24]. This would lead to a physically more accurate model for the precipitate-dislocation interaction, which could then be compared to existing MD results [21,22].…”

Section: Discussionmentioning

confidence: 99%

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Multiscale modeling of dislocation-precipitate interactions in Fe: From molecular dynamics to discrete dislocations

et al. 2016

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The stress-driven motion of dislocations in crystalline solids, and thus the ensuing plastic deformation process, is greatly influenced by the presence or absence of various pointlike defects such as precipitates or solute atoms. These defects act as obstacles for dislocation motion and hence affect the mechanical properties of the material. Here we combine molecular dynamics studies with three-dimensional discrete dislocation dynamics simulations in order to model the interaction between different kinds of precipitates and a 1/2〈111〉{110} edge dislocation in BCC iron. We have implemented immobile spherical precipitates into the ParaDis discrete dislocation dynamics code, with the dislocations interacting with the precipitates via a Gaussian potential, generating a normal force acting on the dislocation segments. The parameters used in the discrete dislocation dynamics simulations for the precipitate potential, the dislocation mobility, shear modulus, and dislocation core energy are obtained from molecular dynamics simulations. We compare the critical stresses needed to unpin the dislocation from the precipitate in molecular dynamics and discrete dislocation dynamics simulations in order to fit the two methods together and discuss the variety of the relevant pinning and depinning mechanisms.

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Section: Discussionmentioning

confidence: 99%

“…The same method and simulation cell have been previously used in similar investigations in Refs. [20][21][22]. Some of the results are taken from these references and used as parameters in the DDD simulations.…”

Section: A Molecular Dynamicsmentioning

confidence: 99%

Multiscale modeling of dislocation-precipitate interactions in Fe: From molecular dynamics to discrete dislocations

et al. 2016

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“…Prolonged irradiation of iron results in several types of defect clusters, including dislocation loops, both interstitial-and vacancy-type, as well as voids and interstitial-rich C15 Laves-phase clusters [3,4,[6][7][8], the last one theoretically shown to be stable. All of these features will affect the dislocation movement in their own manner [9][10][11][12][13][14][15], and hence affect the material properties. The experimentally observed defect saturation has also been reproduced by computational means previously for metals [16][17][18].…”

Section: Introductionmentioning

confidence: 99%

Cascade overlap with vacancy-type defects in Fe

2019

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In order to understand the effect of irradiation on the material properties, we need to look into the atomistic evolution of the system during the recoil event. The nanoscale features formed due to irradiation will ultimately affect the macroscopic properties of the material. The defect production in pristine materials have been subject to investigation previously, but as the dose increases, overlap will start to happen. This effect of cascades overlapping with pre-existing debris has only recently been touched, and mainly been investigated for interstitial-type defects. We focus on vacancy-type defect clusters in BCC Fe and start a recoil event in their near vicinity. The final defect number as well as the transformation of the defect clusters are investigated, and their behaviour is related to the distance between the defect and the cascade centre. We found that for vacancy-type defects, the suppression of defect production is not as strong as previously observed for interstitial-type defects. The cascade-induced transformation, such as change in Burgers vector or creation of dislocations, was determined for all initial defect structures.

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“…The effect of these different features on the dynamics of individual dislocation lines has been studied in detail with molecular dynamics (MD) simulations for some time. Recent examples include refs 16 – 24 . MD simulations give valuable insight into the physical mechanisms of dislocation-defect interactions, but the computational limitations of simulating materials at atomic resolution constrain the system size usually to a singular dislocation and a few defects.…”

Section: Introductionmentioning

confidence: 99%

Effects of precipitates and dislocation loops on the yield stress of irradiated iron

Lehtinen

Laurson

Granberg

et al. 2018

Sci Rep

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Plastic deformation of crystalline materials is governed by the features of stress-driven motion of dislocations. In the case of irradiated steels subject to applied stresses, small dislocation loops as well as precipitates are known to interfere with the dislocation motion, leading to an increased yield stress as compared to pure crystals. We study the combined effect of precipitates and interstitial glissile dislocation loops on the yield stress of iron, using large-scale three-dimensional discrete dislocation dynamics simulations. Precipitates are included in the simulations using our recent multi-scale implementation [A. Lehtinen et al., Phys. Rev. E 93 (2016) 013309], where the strengths and pinning mechanisms of the precipitates are determined from molecular dynamics simulations. In the simulations we observe dislocations overcoming precipitates with an atypical Orowan mechanism which results from pencil-glide of screw segments in iron. Even if the interaction mechanisms with dislocations are quite different, our results suggest that in relative terms, precipitates and loops of similar sizes contribute equally to the yield stress in multi-slip conditions.

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Interaction of dislocations with carbides in BCC Fe studied by molecular dynamics

Cited by 21 publications

References 35 publications

Multiscale modeling of dislocation-precipitate interactions in Fe: From molecular dynamics to discrete dislocations

Multiscale modeling of dislocation-precipitate interactions in Fe: From molecular dynamics to discrete dislocations

Cascade overlap with vacancy-type defects in Fe

Effects of precipitates and dislocation loops on the yield stress of irradiated iron

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