Material properties and their influence on the behaviour of tungsten as plasma facing material

Wirtz, M.; Uytdenhouwen, I.; Barabash, V.; Escourbiac, F.; Hirai, T.; Linke, J.; Loewenhoff, Thorsten; Panayotis, S.; Pintsuk, G.

doi:10.1088/1741-4326/aa6938

Cited by 62 publications

(40 citation statements)

References 24 publications

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“…As a result, the precipitate of W has attracted great interest of many researchers. [ 5–16 ] Recently, Wirtz et al [ 5 ] experimentally investigated the effect of material properties, and W behavior showed that different production processes had certain effects on the anisotropic microstructure and the related material properties of W in the initial state while improving the recrystallization behavior, but thermal shock performance had little impact. Mannheim et al [ 6 ] used a multiscale model to study the long‐term microstructure evolution of W under cascade damage conditions and the distribution of W in nuclear fusion reactor steering gear at different irradiation temperatures.…”

Section: Introductionmentioning

confidence: 99%

Structural, mechanical, electronic, and thermodynamic properties of pure tungsten metal under different pressures: A first‐principles study

Jiang

Zhong

Xiao

et al. 2020

Int J of Quantum Chemistry

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The structural, mechanical, electronic, and thermodynamic properties of pure W metal under different pressures have been investigated using the first-principles method. Our calculated structural parameters are in good agreement with experimental and previous theoretical results. The obtained elastic constants show that pure W metal is mechanically stable. Elastic properties such as the bulk modulus (B), shear modulus (G), Young's modulus (E), Poisson's ratio (ν), Cauchy pressure (C 0 ), and anisotropy coefficients (A) are calculated by the Voigt-Reuss-Hill method. The results show that the pressure can improve the strength of pure tungsten and has little effect on the ductility. In addition, the total density of states as a function of pressure is analyzed. Thermodynamic properties such as the Debye temperature, phonon dispersion spectrum, free energy, entropy, enthalpy, and heat capacity are also discussed. K E Y W O R D S electronic properties, first principles, mechanical properties, structural properties, thermodynamic properties, pure W under pressure

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Section: Introductionmentioning

confidence: 99%

Structural, mechanical, electronic, and thermodynamic properties of pure tungsten metal under different pressures: A first‐principles study

Jiang

Zhong

Xiao

et al. 2020

Int J of Quantum Chemistry

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“…Pure tungsten (W) is considered for plasma-facing materials of the fusion reactors including diverter components [1][2][3][4]. For fusion applications, tungsten has various advantages such as high melting point, high thermal conductivity, low tritium retention, and low material erosion for application as diverter materials [1].…”

Section: Introductionmentioning

confidence: 99%

Measurement of Fracture Toughness of Pure Tungsten Using a Small-Sized Compact Tension Specimen

et al. 2020

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The evaluation of fracture toughness of pure tungsten is essential for the structural integrity analysis in a fusion reactor. Therefore, the accurate quantification of fracture toughness of tungsten alloys is needed. However, due to the inherent brittleness of tungsten, it is difficult to introduce a sharp fatigue pre-crack needed for the fracture toughness test. In this study, a novel fatigue pre-cracking method was developed and applied to the small-sized disc-type compact tension (DCT) specimens of double-forged pure tungsten. To overcome the brittleness and poor oxidation resistance, a low-frequency tensile fatigue pre-cracking was performed at 600 °C in Ar environment, which resulted in the introduction of a sharp pre-crack to DCT specimens. Then, fracture toughness tests were conducted at room temperature (RT), 400 °C, and 700 °C in air and Ar gas environments using as-machined and pre-cracked DCT specimens. At RT and 400 °C, the test environment and crack tip radius did not affect the fracture toughness measurement. However, at 700 °C, the Ar gas environment and the presence of a sharp fatigue pre-crack resulted in a decrease in the measured fracture toughness. Thus, it was suggested that, for the conservative fracture toughness measurement of pure tungsten, fatigue pre-cracking and fracture toughness test should be performed in an inert environment, especially for high-temperature tests.

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“…However, the testing temperature may have been too low in that analysis to improve the ductility (below the brittle-to-ductile transition temperature, which is reported to increase by recrystallization). On the other hand, there are also examples in literature where the ductility of tungsten increases after recrystallization, such as by Wirtz et al [7], who found for several grades of tungsten a significantly improved uniform elongation and total elongation in post-recrystallization (accompanied by a lower yield strength), or [8], where fracture strains were reported of 17% and 22% prior to recrystallization and 68% after recrystallization. The impurity content of the tungsten grade may play a role in the grain boundary cohesion [9], which can affect the ductility.…”

Section: Introductionmentioning

confidence: 99%

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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Material properties and their influence on the behaviour of tungsten as plasma facing material

Abstract: The views and opinions expressed herein do not necessarily reflect those of the ITER Organization.

Cited by 62 publications

References 24 publications

Structural, mechanical, electronic, and thermodynamic properties of pure tungsten metal under different pressures: A first‐principles study

Structural, mechanical, electronic, and thermodynamic properties of pure tungsten metal under different pressures: A first‐principles study

Measurement of Fracture Toughness of Pure Tungsten Using a Small-Sized Compact Tension Specimen

Controlled irradiation hardening of tungsten by cyclic recrystallization

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