Influence of grain boundaries on the radiation-induced defects and hydrogen in nanostructured and coarse-grained tungsten

Valles, G.; Panizo-Laiz, M.; González, César; Martín-Bragado, Ignacio; González-Arrabal, R.; Gordillo, N.; Rodríguez, Iglesias; Guerrero, C.; Perlado, J.M.; Rivera, Alejandro

doi:10.1016/j.actamat.2016.10.007

Cited by 81 publications

(79 citation statements)

References 64 publications

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“…Tungsten, the metal with the highest melting point, has many unique physical properties such as high density, high hardness, low vapor pressure, low thermal expansion coefficient, and excellent thermal conductivity . Due to these outstanding properties, tungsten and its alloys have been widely applied in the fields of defense, medical, and nuclear fusion.…”

Section: Introductionmentioning

confidence: 99%

Selective Laser Melting and Remelting of Pure Tungsten

et al. 2020

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The processing of pure tungsten encounters a substantial challenge due to its high melting point and intrinsic brittleness. Selective laser melting (SLM) technique is gaining popularity and offers an excellent processing approach for refractory metals. Herein, dense pure tungsten specimens are produced by optimizing SLM processing parameters. The mechanical property of the SLM‐produced tungsten with an ultimate compressive strength of about 1200 MPa, which is obviously superior to that reported in other literature, is achieved. The increased laser energy input is instrumental in raising density and surface roughness of tungsten specimens. Interestingly, additional remelting of processed layers during SLM improves the surface quality and the microstructure and achieves the highest relative density (98.4% ± 0.5%). After laser remelting, the surface roughness is reduced by 28% and a large number of fine grains are obtained. The flow of fluids caused by remelting plays a decisive role in the formation of fine grains and the defect level. Therefore, these findings offer a new insight into SLM of pure tungsten.

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Section: Introductionmentioning

confidence: 99%

Selective Laser Melting and Remelting of Pure Tungsten

et al. 2020

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“…To date, it is generally believed that hydrogen bubble nucleation by self-clustering like the case of helium in metals [5,6] would be impossible given the H-H strong repulsion or very weak attraction in metals [7][8][9][10][11][12][13][14], and that, as suggested by many previous studies [4,7,8,10,11], hydrogen bubble nucleation would require the presence of lattice defects. The hydrogen bubble nucleation can be either heterogeneous, relating to grain boundaries, [15][16][17][18] dislocations, [18] and impurities, [7,19] or homogeneous, arising from the aggregation of vacancies or vacancy-hydrogen complexes. [20,21] However, hydrogen bubble formation in metals with extremely low concentration of the lattice defects has been clearly observed in many experiments.…”

Section: Introductionmentioning

confidence: 99%

Hydrogen bubble nucleation by self-clustering: density functional theory and statistical model studies using tungsten as a model system

Hou¹,

Kong²,

Sun³

et al. 2018

Nucl. Fusion

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Low-energy hydrogen irradiation is known to induce bubble formation in tungsten, while its atomistic mechanisms remain little understood. Using first-principles calculations and statistical models, we studied the self-clustering behavior of hydrogen in tungsten. Unlike previous speculations that hydrogen self-clusters are energetically unstable owing to the general repulsion between two hydrogens, we demonstrated that hydrogen self-cluster becomes more favorable as the cluster size increases. We found that hydrogen atoms would form two-dimensional platelet-like structures along {100} planes. These hydrogen self-clustering behaviors can be quantitative understood by the competition between long-ranged elastic attraction and local electronic repulsion. Further statistical analysis showed that there exists a critical hydrogen concentration above which hydrogen self-clusters are thermodynamically stable and kinetically feasible. Based on this critical hydrogen concentration, the plasma loading conditions under which hydrogen self-clusters form were predicted. Our predictions showed excellent agreement with experimental results of hydrogen bubble formation in tungsten exposed to low-energy hydrogen irradiation. Finally, we proposed a possible mechanism for the hydrogen bubble nucleation via hydrogen self-clustering. This work provides mechanistic insights and quantitative models towards understanding of plasma-induced hydrogen bubble formation in plasma-facing tungsten.

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“…In intimate connection with artificial intelligence concepts, appropriately configured computational programming and access to high-throughput resources allows a machine to extract patterns and learn from pre-existing data bases much faster and more accurately than ever before, iterating the processes until fully satisfying relationships and results have been obtained and, in doing so, reducing human intervention to a minimum. Interatomic potential fitting for ulterior MD modelling (Atomistica [311], Atomicrex [312], Potfit [313], OpenKIM [314]), hybrid DFT(Density Functional Theory)-MD simulations (Gaussian approximation potential (GAP) [315], SNAP [316]) or DFT-KMC [317,318] and finite element [319][320][321] multiscale modelling approaches are paradigmatic examples of advanced materials simulation methodologies that make use of machine learning-related techniques. The scaling up from ab-initio and atomistic time and lengths to mesoscopic and macroscopic scales benefits enormously from these kinds of procedures, as stated in several different recent reviews ( Figure 20).…”

Section: Machine Learningmentioning

confidence: 99%

The Critical Raw Materials in Cutting Tools for Machining Applications: A Review

et al. 2020

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A variety of cutting tool materials are used for the contact mode mechanical machining of components under extreme conditions of stress, temperature and/or corrosion, including operations such as drilling, milling turning and so on. These demanding conditions impose a seriously high strain rate (an order of magnitude higher than forming), and this limits the useful life of cutting tools, especially single-point cutting tools. Tungsten carbide is the most popularly used cutting tool material, and unfortunately its main ingredients of W and Co are at high risk in terms of material supply and are listed among critical raw materials (CRMs) for EU, for which sustainable use should be addressed. This paper highlights the evolution and the trend of use of CRMs) in cutting tools for mechanical machining through a timely review. The focus of this review and its motivation was driven by the four following themes: (i) the discussion of newly emerging hybrid machining processes offering performance enhancements and longevity in terms of tool life (laser and cryogenic incorporation); (ii) the development and synthesis of new CRM substitutes to minimise the use of tungsten; (iii) the improvement of the recycling of worn tools; and (iv) the accelerated use of modelling and simulation to design long-lasting tools in the Industry-4.0 framework, circular economy and cyber secure manufacturing. It may be noted that the scope of this paper is not to represent a completely exhaustive document concerning cutting tools for mechanical processing, but to raise awareness and pave the way for innovative thinking on the use of critical materials in mechanical processing tools with the aim of developing smart, timely control strategies and mitigation measures to suppress the use of CRMs.

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Influence of grain boundaries on the radiation-induced defects and hydrogen in nanostructured and coarse-grained tungsten

Cited by 81 publications

References 64 publications

Selective Laser Melting and Remelting of Pure Tungsten

Selective Laser Melting and Remelting of Pure Tungsten

Hydrogen bubble nucleation by self-clustering: density functional theory and statistical model studies using tungsten as a model system

The Critical Raw Materials in Cutting Tools for Machining Applications: A Review

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