Ab initio modelling of vacancy–solute dragging in dilute irradiated iron-based alloys

Messina, Luca; Chang, Zhongwen; Olsson, Pär

doi:10.1016/j.nimb.2013.01.049

Cited by 24 publications

(16 citation statements)

References 33 publications

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“…Vacancy-solute clusters are a documented phenomenon 59,60 and the binding of solute atoms to vacancies in -Fe is important for understanding solute partitioning, diffusivity and precipitation [61][62][63] . In Figure 9(A-C), the resultant magnetic moment, binding energy and vacancy formation energy of Mn substitution are shown as a function of distance from a vacancy from 1 st  6 th nn.…”

Section: Effect Of Vacanciesmentioning

confidence: 99%

Density functional theory study of the magnetic moment of solute Mn in bcc Fe

et al. 2018

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Abstract. An unexplained discrepancy exists between the experimentally measured and theoretically calculated magnetic moments of Mn in -Fe. In this study, we use density functional theory to suggest that this discrepancy is likely due to the local strain environment of a Mn atom in the Fe structure. The ferromagnetic coupling, found by experiment, was shown to be metastable and could be stabilised by a 2% hydrostatic compressive strain. The effects of Mn concentration, vacancies and interstitial defects on the magnetic moment of Mn are also discussed. It was found that the ground state, antiferromagnetic (AFM) coupling of Mn to Fe requires long range tensile relaxations of the neighbouring atoms along <111> which is hindered in the presence of other Mn atoms. Vacancies and Fe interstitial defects stabilise the AFM coupling but are not expected to have a large effect on the average measured magnetic moment.

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Section: Effect Of Vacanciesmentioning

confidence: 99%

Density functional theory study of the magnetic moment of solute Mn in bcc Fe

et al. 2018

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“…Those diffusion models were limited to short-range interacting alloys and the contribution to the L ij coefficients of some vacancy jumps beyond the first nearest neighbor sites of the solute atom had to be neglected. Recently, long-range interaction models of the L ij coefficients have been developed [15,16]). In concentrated alloys, due to the high complexity, approximate mean field methods are used to determine the L ij coefficients [3].…”

Section: Segregationmentioning

confidence: 99%

Modeling radiation induced segregation in iron–chromium alloys

et al. 2016

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International audienceRadiation induced segregation in ferritic Fe-Cr alloys is studied by Atomistic Kinetic Monte Carlo simulations that include diffusion of chemical species by vacancy and interstitial migration, recombination, and elimination at sinks. The parameters of the diffusion model are fitted to DFT calculations. Transport coefficients that control the coupling between diffusion of defects and chemical species are measured in dilute and concentrated alloys. Radiation induced segregation near grain boundaries is directly simulated with this model. We find that the diffusion of vacancies toward sinks leads to a Cr depletion. Meanwhile, the diffusion of self-interstitials causes an enrichment of Cr in the vicinity of sinks. For concentrations lower than 15%Cr, we predict that sinks will be enriched with Cr for temperatures lower than a threshold. When the temperature is above this threshold value, the sinks will be depleted in Cr. These results are compared to previous experimental studies and models. Cases of radiation induced precipitation and radiation accelerated precipitation are considered. (c) 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved

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“…The former by calculating the diffusion barrier of vacancy with different diffusion paths can calculate the solvent and solute diffusion coefficient. 43,44 The latter by calculating the MSD of Cu atom and applying the Einstein equation calculate the Cu diffusion coefficient. 40,41 For example, using MD method, J. Marian et al 41 studied the Cu diffusion coefficient in a Fe-0.9 at% Cu alloy at high temperature (1000∼1750 K) and showed that the vacancies were clustering when vacancy concentration arrived 1%, and they also pointed out that clustering vacancy had no significant influence upon the Cu diffusion coefficient.…”

Section: Simulation Methodsmentioning

confidence: 99%

“…40,41 For example, using MD method, J. Marian et al 41 studied the Cu diffusion coefficient in a Fe-0.9 at% Cu alloy at high temperature (1000∼1750 K) and showed that the vacancies were clustering when vacancy concentration arrived 1%, and they also pointed out that clustering vacancy had no significant influence upon the Cu diffusion coefficient. The LeClaire multi-frequency model assume that the vibration frequency of Cu is same as that of the Fe atom (4.9∼5.2 THz) due to the volume of Cu atom is almost as large as the volume of Fe atom, 44 this assumption may lead to an uncertainty in the calculation of the Cu diffusion coefficient. In this paper, we used the MD method to calculate the Cu atom diffusion coefficient with a vacancy concentration of 0.1 at.%, 0.2 at.% and 0.3 at.% at different temperature (1200∼1600 K), and we maintained the high temperature in order to enhance statistics of the vacancy jumps.…”

Section: Simulation Methodsmentioning

confidence: 99%

Vacancy enhanced formation and phase transition of Cu-rich precipitates in α - iron under neutron irradiation

Zhang

et al. 2016

AIP Advances

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In this paper, we employed both molecular statics and molecular dynamics simulation methods to investigate the role of vacancies in the formation and phase transition of Cu-rich precipitates in α-iron. The results indicated that vacancies promoted the diffusion of Cu atoms to form Cu-rich precipitates. After Cu-rich precipitates formed, they further trapped vacancies. The supersaturated vacancy concentration in the Cu-rich precipitate induced a shear strain, which triggered the phase transition from bcc to fcc structure by transforming the initial bcc (110) plane into fcc (111) plane. In addition, the formation of the fcc-twin structure and the stacking fault structure in the Cu-rich precipitates was observed in dynamics simulations.

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Ab initio modelling of vacancy–solute dragging in dilute irradiated iron-based alloys

Cited by 24 publications

References 33 publications

Density functional theory study of the magnetic moment of solute Mn in bcc Fe

Density functional theory study of the magnetic moment of solute Mn in bcc Fe

Modeling radiation induced segregation in iron–chromium alloys

Vacancy enhanced formation and phase transition of Cu-rich precipitates in α - iron under neutron irradiation

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