Vacancy–solute interactions in ferromagnetic and paramagnetic bcc iron: Ab initio calculations

Gorbatov, Oleg I.; Korzhavyi, Pavel A.; Ruban, Andrei V.; Johansson, Börje; Gornostyrev, Yu. N.

doi:10.1016/j.jnucmat.2011.09.002

Cited by 65 publications

(22 citation statements)

References 50 publications

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“…The interaction of Nb-vacancy is attractive (0.23 eV) in 1nn configuration, but exhibits a small repulsion ( − 0.09 eV) in 2nn configuration, which is in good agreement with results due to Olsson and Gorbatov et al 26,27) For the case of La-Nb pair, the calculations indicate that repulsive interactions exist in both 1nn and 2nn shells. Similar results have been reported by You et al 28) From Table 4 it can be seen that referring to the 1nn and 2nn configurations of La-vacancy pairs, the binding energies are all positive, which implies that attraction between La and vacancy in the both nearest neighbor shells.…”

Section: (14)supporting

confidence: 90%

Effect of Lanthanum on the Precipitation of NbC in Ferritic Steels

et al. 2016

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The effect of lanthanum on the precipitation of NbC in ferritic steel has been studied within the experimental and theory methods. The diffusion coefficients of Niobium resulted from the diffusion couple experiment shows that Nb diffuses slightly faster in the presence of La than that in pure α-Fe. Using the first-principles calculations based on the density functional theory, we studied the interactions between any two defects of La, Nb and vacancy, as well as the variation of diffusion activation energies caused by the presence of La. The interactions between La and Nb are calculated to be repulsive in both the first and the second nearest neighbor configurations, and the vacancy is expected to form in the La-Nb clustering area, which leads to the decrease of the diffusion activation energy of Nb. To elucidate the effect of La on the precipitation of NbC in ferritic steel, the above diffusion coefficients were substituted into the precipitation kinetics model. Agree with the experimental data, the simulated evolutions of the fractions and radius of NbC precipitate reveal that the addition of La leads to the faster precipitation kinetics of NbC in ferritic steels.

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Section: (14)supporting

confidence: 90%

Effect of Lanthanum on the Precipitation of NbC in Ferritic Steels

et al. 2016

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“…The calculated lifetimes, using Finnis-Sinclair N-body potential, of a positron trapped in vacancy clusters consisting of two and three vacancies associated with edge dislocations are 157 and 167 ps, respectively [18]. Taking into account that attractive interaction energy between vacancy and edge dislocation is much greater than between vacancy and Re impurity [11,15], the first explanation seems rather unlikely. Moreover, a more detailed spectra analysis using two-state trapping model reveals that the longer positron annihilation lifetime s 2 increases with T. This result also favours creation of vacancy clusters associated with edge dislocations over formation of v-Re pairs.…”

Section: Methodsmentioning

confidence: 98%

“…A phenomenon which should be taken under consideration in this type of study is the interaction between impurity atoms and vacancies. In two recent papers [10,11], the authors present theoretical calculations based on density functional theory (DFT), which suggests that the interaction between vacancies and transition-metal impurities dissolved in iron-based alloys is attractive. These results lead to the conclusion that in the iron-based alloy which contains vacancies and transition-metal impurities, an energetically favourable pairing process should generate vacancy-impurity pairs in large numbers.…”

Section: Introductionmentioning

confidence: 99%

Behaviour of vacancies in dilute Fe–Re alloys: a positron annihilation study

Idczak

Konieczny

2014

Appl. Phys. A

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Positron annihilation lifetime spectroscopy was used in a room temperature study of the influence of heat treatment on behaviour of vacancies in Fe 0.97 Re 0.03 and Fe 0.94 Re 0.06 alloys. In this experiment, the vacancies were created during the formation and further mechanical processing of the iron systems under consideration so the lifetime spectra of positrons were collected at least twice. The first samples were taken just after the melting process in an arc furnace, and the second ones were taken for the specimens annealed at 1,270 K and then cold-rolled at room temperature. After that, the spectra were measured for all studied samples after annealing at some temperatures gradually increasing from 300 to 1,270 K. It was found that vacancy-Re pairs are the dominant type of structural defects in alloys just after the melting process. In the case of alloys after a cold rolling process, the dominant type of structural defects is vacancies associated with edge dislocations. Moreover, for cold-rolled samples annealed at 473-573 K, the growth of the vacancy clusters associated with edge dislocations is observed by an increase in the mean positron lifetime. Finally, at temperatures above 573 K, vacancy clusters associated with edge dislocations as well as vacancy-Re pairs become unstable, and freely migrating vacancies sink at grain boundaries.

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“…To compare with previous MD studies [24,35,36] and DFT calculations [17,[37][38][39][40][41][42], the binding energies for Cu-V, Cu-Cu and Cu-SIA defect pairs are listed in Table 1. Our results are almost identical to those given by Pasianot et al [24] since they are produced by the same potential.…”

Section: Cu-point Defects Interactionmentioning

confidence: 99%

Preferential Cu precipitation at extended defects in bcc Fe: An atomistic study

Zhang

Millett

Tonks

et al. 2015

Computational Materials Science

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a b s t r a c tAs a starting point to understand Cu precipitation in RPV alloys, molecular dynamics and Metropolis Monte-Carlo simulations are carried out to study the effect of lattice defects on Cu precipitation by taking Fe-Cu system as a model alloy. Molecular dynamics simulations show that owing to the high heat of mixing and positive size mismatch, Cu is attracted by vacancy type defects such as vacancies and voids, and tensile stress fields. In accordance, preferential precipitation of Cu is observed in Metropolis Monte-Carlo simulations at dislocations, prismatic loops and voids. The interaction of Cu with a stress field, e.g., that associated with a dislocation or a prismatic loop, is dominated by elastic effect and can be well described by the linear-elasticity theory. For prismatic loops, the attraction to Cu is found to be size-dependent with opposite trends displayed by vacancy and interstitial loops. The size-dependences can be explained by considering the stress fields produced by these loops. The current results will be useful for understanding the effect of neutron irradiation on Cu precipitation in reactor-pressure-vessel steels.

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Vacancy–solute interactions in ferromagnetic and paramagnetic bcc iron: Ab initio calculations

Cited by 65 publications

References 50 publications

Effect of Lanthanum on the Precipitation of NbC in Ferritic Steels

Effect of Lanthanum on the Precipitation of NbC in Ferritic Steels

Behaviour of vacancies in dilute Fe–Re alloys: a positron annihilation study

Preferential Cu precipitation at extended defects in bcc Fe: An atomistic study

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