Ion-irradiation induced clustering in W-Re-Ta, W-Re and W-Ta alloys: An atom probe tomography and nanoindentation study

Xu, Alan; Armstrong, David E.J.; Beck, Christian E.; Moody, Michael P.; Smith, George Davey; Bagot, Paul A.J.; Roberts, Steve

doi:10.1016/j.actamat.2016.10.050

Cited by 121 publications

(56 citation statements)

References 30 publications

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“…For example, Klimenkov et al note that Re-rich particles not associated with cavities formed in neutron-irradiated single crystal W [19]. As well, using atom-probe tomography Xu et al have performed detailed analyses of Rerich atmospheres in bcc W without detecting significant numbers of vacancies [14].…”

Section: Second There Is Clear Experimental Evidence Ofmentioning

confidence: 99%

“…The next question we address is the solute concentration inside the precipitate. Xu et al [13,14] have performed detailed atom probe analyses of radial concentration profiles at 573 and 773 K and find that the precipitates that form might be better characerized as 'solute clouds', reaching concentrations of around 30% in the center gradually declining as the radius increases. Our analysis is shown in Figure 12, with results averaged over the 8 cases tried here.…”

Section: Kinetic Monte Carlo Simulationsmentioning

confidence: 99%

“…These particles were formed independently of cavities". We leave out heterogeneous precipitation at voids, as the evidence in the literature is conflicting at this stage: discounted in some works [14,24] and observed in others [19].…”

Section: Implications Of Our Studymentioning

confidence: 99%

“…Radial concentration profile as a function of time for the precipitates formed in the kMC simulations. The experimental results are taken from the work by Xu et al[14].…”

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confidence: 99%

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Mechanism of nucleation and incipient growth of Re clusters in irradiated W-Re alloys from kinetic Monte Carlo simulations

et al. 2017

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7High-temperature, high-dose, neutron irradiation of W results in the formation of Re-rich clusters at concentrations one order of magnitude lower than the thermodynamic solubility limit. These clusters may eventually transform into brittle W-Re intermetallic phases, which can lead to high levels of hardening and thermal conductivity losses. Standard theories of radiation enhanced diffusion and precipitation cannot explain the formation of these precipitates and so understanding the mechanism by which nonequilibrium clusters form under irradiation is crucial to predict materials degradation and devise mitigation strategies. Here we carry out a thermodynamic study of W-Re alloys and conduct kinetic Monte Carlo simulations of Re cluster formation in irradiated W2Re alloys using a generalized Hamiltonian for crystals containing point defects parameterized entirely with electronic structure calculations. Our model incorporates recently-gained mechanistic information of mixedinterstitial solute transport, which is seen to control cluster nucleation and growth by forming quasi-spherical nuclei after an average incubation time of 13.5(±8.5) s at 1800 K. These nuclei are seen to grow by attracting more mixed interstitials bringing solute atoms, which in turns attracts vacancies leading to recombination and solute agglomeration. Owing to the arrival of both Re and W atoms from the mixed dumbbells, the clusters are not fully dense in Re, which amounts to no more than 50% of the atomic concentration of the cluster near the center. Our simulations are in qualitative agreement with recent atom probe examinations of ion irradiated W-2Re systems at 773 K.

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Section: Second There Is Clear Experimental Evidence Ofmentioning

confidence: 99%

Section: Kinetic Monte Carlo Simulationsmentioning

confidence: 99%

Section: Implications Of Our Studymentioning

confidence: 99%

“…Radial concentration profile as a function of time for the precipitates formed in the kMC simulations. The experimental results are taken from the work by Xu et al[14].…”

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confidence: 99%

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Mechanism of nucleation and incipient growth of Re clusters in irradiated W-Re alloys from kinetic Monte Carlo simulations

et al. 2017

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“…Recent reports on self-ion irradiations of W-Ta alloys at temperatures B 500°C and up to a damage level of 33 dpa confirm the absence of radiation-induced Ta clustering. Moreover, the presence of Ta hinders the formation of Re clusters under irradiation [18]. Interstitial-type dislocation loops form at those low irradiation temperatures in W-Ta alloys.…”

Section: Introductionmentioning

confidence: 99%

Thermal Evolution of the Proton Irradiated Structure in Tungsten–5 wt% Tantalum

et al. 2017

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We have monitored the thermal evolution of the proton irradiated structure of W-5 wt% Ta alloy by in-situ annealing in a transmission electron microscope at fusion reactor temperatures of 500-1300°C. The interstitial-type a/2\111[ dislocation loops emit self-interstitial atoms and glide to the free sample surface during the early stages of annealing. The resultant vacancy excess in the matrix originates vacancy-type a/2\111[ dislocation loops that grow by loop and vacancy absorption in the temperature range of 600-900°C. Voids form at 1000°C, by either vacancy absorption or loop collapse, and grow progressively up to 1300°C. Tantalum delays void formation by a vacancy-solute trapping mechanism.

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Highly Enhanced Transport by Supersonic N‐Crowdions

Dmitriev

Medvedev

Chetverikov

et al. 2017

Physica Rapid Research Ltrs

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An interstitial atom placed in a close‐packed atomic row of a crystal is called crowdion. Such defects are highly mobile, they can move along the row transporting mass and energy. In the present study the concept of the classical supersonic crowdion is generalized to N‐crowdion in which not one but N atoms move simultaneously at a high speed. With the help of molecular dynamics simulations for fcc Morse crystal it is demonstrated that N‐crowdions are much more efficient in mass transport being able to propagate through larger distances having smaller total energy than the classical 1‐crowdion.

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Ion-irradiation induced clustering in W-Re-Ta, W-Re and W-Ta alloys: An atom probe tomography and nanoindentation study

Cited by 121 publications

References 30 publications

Mechanism of nucleation and incipient growth of Re clusters in irradiated W-Re alloys from kinetic Monte Carlo simulations

Mechanism of nucleation and incipient growth of Re clusters in irradiated W-Re alloys from kinetic Monte Carlo simulations

Thermal Evolution of the Proton Irradiated Structure in Tungsten–5 wt% Tantalum

Highly Enhanced Transport by Supersonic N‐Crowdions

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