Irradiation hardening of pure tungsten exposed to neutron irradiation

Hu, Xunxiang; Koyanagi, Takaaki; Fukuda, Makoto; Kumar, Nitin; Snead, Lance Lewis; Wirth, Brian D.; Katoh, Yutai

doi:10.1016/j.jnucmat.2016.08.024

Cited by 216 publications

(120 citation statements)

References 44 publications

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“…The lifetime of the tungsten monoblocks under heat and neutron irradiation will depend strongly on the evolution of the strength and ductility of the material. A high hardness, which is reported for fission-neutron-irradiated tungsten [2,3] can be associated to a high yield strength and low ductility.…”

Section: Introductionmentioning

confidence: 77%

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Controlled irradiation hardening of tungsten by cyclic recrystallization

Mannheim¹,

Dommelen²,

Geers³

2019

Modelling Simul. Mater. Sci. Eng.

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The economical lifetime of the divertor is a key concern for realizing nuclear fusion reactors that may solve the world's energy problem. A main risk is thermo-mechanical failure of the plasma-facing tungsten monoblocks, as a consequence of irradiation hardening induced by neutron displacement cascades. Lifetime extensions that could be carried out without prolonged maintenance periods are desired. In this work, the effects of potential treatments for extending the lifetime of an operational reactor are explored. The proposed treatments make use of cyclic recrystallization processes that can occur in neutron-irradiated tungsten. Evolution of the microstructure under non-isothermal conditions is investigated, employing a multi-scale model that includes a physically-based mean-field recrystallization model and a cluster dynamics model for neutron irradiation effects. The model takes into account microstructural properties such as grain size and displacement-induced defect concentrations. The evolution of a hardness indicator under neutron irradiation was studied. The results reveal that, for the given microstructure and under the assumed model behaviour, periodical extra heating can have a significant positive influence on controlling the irradiation hardening. For example, at 800°C, if extra annealing at 1200°C was applied after every 100 hrs for the duration of 1 hr, then the hardness indicator reduces from maximum 140 to below 70. * Correspondence to J.A.W. van Dommelen. Electronic mail: j.a.w.v.dommelen@tue.nl arXiv:1901.05859v1 [cond-mat.mtrl-sci]

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Section: Introductionmentioning

confidence: 77%

“…The displacement defects in the lattice induce hardening of the material, as they form obstacles for dislocation motion. A hardness indicator I H , based on the Dispersed Barrier Hardening model, is used to qualitatively study the evolution of the hardness under irradiation [2,12]:…”

Section: Hardeningmentioning

confidence: 99%

Controlled irradiation hardening of tungsten by cyclic recrystallization

Mannheim¹,

Dommelen²,

Geers³

2019

Modelling Simul. Mater. Sci. Eng.

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“…where α is the barrier strength coefficient, M the Taylor factor (2.7), µ the shear modulus of tantalum (69 GPa), b the Burgers vector of the dislocations (2.76Å), N the density and d the average size of the obstacles (Seeger, 1958;Rosenberg & Piehler, 1971). The value of α depends on the defect type and size for a given temperature (Hu et al, 2016). A value of α = 0.2 has been reported for dislocations in tantalum (Yasunaga et al, 2000), whereas it takes a value of α = 0.25 in the case of voids with a diameter of 1-2 nm (Hu et al, 2016).…”

Section: Void Formationmentioning

confidence: 99%

“…The value of α depends on the defect type and size for a given temperature (Hu et al, 2016). A value of α = 0.2 has been reported for dislocations in tantalum (Yasunaga et al, 2000), whereas it takes a value of α = 0.25 in the case of voids with a diameter of 1-2 nm (Hu et al, 2016). The change in hardness ( H ) corresponds to:…”

Section: Void Formationmentioning

confidence: 99%

Characterisation of lattice damage formation in tantalum irradiated at variable temperatures

Ipatova

Wady

Shubeita

et al. 2017

Journal of Microscopy

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The formation of radiation-induced dislocation loops and voids in tantalum at 180(2), 345(3) and 590(5)°C was assessed by 3MeV proton irradiation experiments and subsequent damage characterisation using transmission electron microscopy. Voids formed at 345(3)°C and were arranged into a body centred cubic lattice at a damage level of 0.55 dpa. The low vacancy mobility at 180(2)°C impedes enough vacancy clustering and therefore the formation of voids visible by TEM. At 590(5)°C the Burgers vector of the interstitial-type dislocation loops is a<100>, instead of the a/2 <111> Burgers vector characteristic of the loops at 180(2) and 345(3)°C. The lower mobility of a<100> loops hinders the formation of voids at 590(5)°C up to a damage level of 0.55 dpa.

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“…However the inherent low-temperature brittleness and recrystallization or irradiation induced embrittlement of tungsten severely limit its application in the extreme conditions of simultaneous high temperature and high flux neutron irradiation [4][5][6]. So it is important to decrease the embrittlement of tungsten materials.…”

Section: Introductionmentioning

confidence: 99%

Comparative Investigation of Tungsten Fibre Nets Reinforced Tungsten Composite Fabricated by Three Different Methods

Zhang

Jiang

Fang

et al. 2017

Metals

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Tungsten fibre nets reinforced tungsten composites (W f /W) containing four net layers were fabricated by spark plasma sintering (SPS), hot pressing (HP) and cold rolling after HP (HPCR), with the weight fraction of fibres being 17.4%, 10.5% and 10.5%, respectively. The relative density of the HPCRed samples is the highest (99.8%) while that of the HPed composites is the lowest (95.1%). Optical and scanning electron microscopy and electron back scattering diffraction were exploited to characterize the microstructure, while tensile and hardness tests were used to evaluate the mechanical properties of the samples. It was found that partial recrystallization of fibres occurred after the sintering at 1800 • C. The SPSed and HPed W f /W composites begin to exhibit plastic deformation at 600 • C with tensile strength (TS) of 536 and 425 MPa and total elongation at break (TE) of 11.6% and 23.0%, respectively, while the HPCRed W f /W composites exhibit plastic deformation at around 400 • C. The TS and TE of the HPCRed W f /W composites at 400 • C are 784 MPa and 8.4%, respectively. The enhanced mechanical performance of the W f /W composites over the pure tungsten can be attributed to the necking, cracking, and debonding of the tungsten fibres.

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Irradiation hardening of pure tungsten exposed to neutron irradiation

Cited by 216 publications

References 44 publications

Controlled irradiation hardening of tungsten by cyclic recrystallization

Controlled irradiation hardening of tungsten by cyclic recrystallization

Characterisation of lattice damage formation in tantalum irradiated at variable temperatures

Comparative Investigation of Tungsten Fibre Nets Reinforced Tungsten Composite Fabricated by Three Different Methods

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