First-principles investigation on vacancy trapping behaviors of hydrogen in vanadium

Gui, Li-Jiang; Liu, Yuelin; Wang, Weitian; Jin, Shuo; Zhang, Ying; Lü, Guang-Hong; Yao, Jing

doi:10.1016/j.jnucmat.2013.03.048

Cited by 29 publications

(27 citation statements)

References 41 publications

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“…The hydrogen embrittlement which is more prominent in Wbased materials combined with refractory metals like W-V, W-Ti, WNb and W-Ta, but it also affects the heavy alloys like W-Fe-Ni as discussed by Bose and German [22]. Hydrogen dissolves easily in V due to the negative formation energy of vacancy-hydrogen complexes [23]. Hence, it is deduced that sintering of W-V materials in hydrogen environment is not feasible.…”

Section: Resultsmentioning

confidence: 99%

Development of tungsten-based materials by different sintering techniques

Arshad¹,

Wang²,

Yuan³

et al. 2015

International Journal of Refractory Metals and Hard Materials

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Section: Resultsmentioning

confidence: 99%

Development of tungsten-based materials by different sintering techniques

Arshad¹,

Wang²,

Yuan³

et al. 2015

International Journal of Refractory Metals and Hard Materials

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“…It is widely believed [12][13][14] that hydrogen in materials can exist in one of the following states: atomic (H 0 ), ionic (H + and H -), molecular (H 2 ), in compounds with metals (hydrides M m H n ), and in compounds with impurities (e.g., CH 4 , H 2 S). In addition, hydrogen can form complexes with point defects, for example, with vacancies H m V n (V means a vacancy; m and n are the number of hydrogen atoms and vacancies in the complex, respectively) and with V vacancies and impurities H m X n V k (X means an intersti tial impurity), and other complexes [15].…”

Section: Resultsmentioning

confidence: 99%

“…1), we have assumed that traps for hydrogen in the temperature range of 780-790 K are such defects, whose energy of binding with hydrogen and hydrogen capacity are not affected by the presence of atoms of the alloying elements in solid solution. Since vanadium hydrides are thermally unstable, namely, they dissolve already at tempera tures from 270 K [16,17], such traps can be thermal vacancies [15], dislocations, grain boundaries, twins, discontinuities, and other hereditary defects, which in combination with hydrogen atoms have a positive binding energy. For example, in α Fe, the binding energy is 0.45-0.53 eV for H-V, 0.71-0.90 eV for H-V m (m > 4), 0.24-0.62 eV for H dislocation, 0.78 eV for H pore, 0.75-0.70 eV for H helium bubble, and 0.29 eV for H-TiC [12].…”

Section: Resultsmentioning

confidence: 99%

“…For example, in α Fe, the binding energy is 0.45-0.53 eV for H-V, 0.71-0.90 eV for H-V m (m > 4), 0.24-0.62 eV for H dislocation, 0.78 eV for H pore, 0.75-0.70 eV for H helium bubble, and 0.29 eV for H-TiC [12]. It is shown by calculation [15] that in vanadium one vacancy can hold twelve hydro gen atoms when they are introduced simultaneously and six hydrogen atoms when they are introduced sequentially. It is shown in [6] that in vanadium alloys the chemical composition of the alloy is responsible for the amount of hydrogen trapped.…”

Section: Resultsmentioning

confidence: 99%

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Hydrogen retention by vanadium-titanium alloys

Zaw

Chernov

Stal’tsov

et al. 2015

Inorg. Mater. Appl. Res.

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INTRODUCTIONVanadium alloys with the rapid reduction of the induced activity of a V-Ti-Cr system are considered to be promising structural materials for application in future fusion reactors (FRs) of a DEMO type [1][2][3]. There is an interesting idea to use vanadium alloys as a fuel element cladding in fast neutron reactors (FNRs) with sodium cooling, where the required high tem perature strength is provided by a vanadium alloy and required corrosion resistance is provided by clad layers made from ferritic steel [4]. Embrittlement of vana dium alloys during operation can occur in contact with hydrogen isotopes [5][6][7][8][9]. For example,in [7], it is shown that a reduction in the relative elongation of V-Ti-Cr alloys in a hydrogen atmosphere (P ≈ 0.13 kPa) begins at a concentration of 360 wppm H 2 . There are a number of sources where hydrogen penetrates into structural material in FRs and FNRs: the main one is transmutation reactions of type (n, p), (n, d), (n, t), and (n, n I p), which have a threshold (energy) char acter. It should be noted that the amount of hydrogen accumulated in vanadium in FRs significantly exceeds that in FNRs. For example, it was calculated that 20 appm is accumulated in vanadium after 560 days of irradiation in the BN 600, whereas ~680 appm H is accumulated in the DEMO RF [10].Hydrogen can be specifically introduced into a liq uid metal coolant to eliminate oxide deposits. Another source of hydrogen input to the structural materials of the first FR wall is plasma radiation.Vanadium alloys which contain titanium, a strong hydride forming element, are currently considered as structural materials for nuclear reactors [3,11,12]. The most promising alloy for application in FR is the ternary alloy V-4% Ti-4% Cr. This work was aimed at finding the regularities of the retention of hydrogen depending on the titanium content in the V-Ti alloys saturated with hydrogen. EXPERIMENTALThe first stage was to produce the samples of V-Ti alloys, namely, to prepare a master alloy (alloy with a maximum titanium content V-10 wt % Ti) by alloying vanadium with titanium in a MIFI 9 vacuum arc fur nace. Model alloys with 0.5, 1, 5, and 10% Ti additions were prepared by alloying the master alloy with vana dium. The content of titanium was determined using a Camebax SX 50 microanalyzer. Pure vanadium served as a reference. The deviation of alloy composition from the calculated one was not more than 5%.After repeated rolling with intermediate homogeniz ing annealing at 1080 K to a final thickness of ~0.25 mm, the samples with dimensions of 25 × 7 × 0.25 mm 3 were annealed in a vacuum of 10 MPa at 1273 K for 2 h and then cooled together with a furnace. Before hydrogen saturation, the samples were electropolished to a mir ror finish in a solution of H 2 SO 4 (concentrate) + 5% ethanol.Abstract-Hydrogen retention in vanadium and its binary alloys with titanium are investigated by means of hydrogen thermal desorption spectrometry. The samples are saturated with hydrogen for 2000 h at a temper ature of 620 K in an...

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“…In the last decade, some theoretical analysis has found that defects such as monovacancy [23], self-interstitial atoms [24,25] and other impurity atoms [26][27][28] could act as the nucleation sites for hydrogen owing to their have the ability to block hydrogen diffusion [29,30] or trap hydrogen [31,32]. However, most of the previous first-principles calculations work is confined to the uncomplicated cases of monovacancies or divacancies, leading to the absence of research on the initial nucleation stage of hydrogen bubble.…”

Section: Introductionmentioning

confidence: 99%

Relationship between the Behavior of Hydrogen and Hydrogen Bubble Nucleation in Vanadium

Wang

et al. 2020

Materials

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Hydrogen plays a significant role in the microstructure evolution and macroscopic deformation of materials, causing swelling and surface blistering to reduce service life. In the present work, the atomistic mechanisms of hydrogen bubble nucleation in vanadium were studied by first-principles calculations. The interstitial hydrogen atoms cannot form significant bound states with other hydrogen atoms in bulk vanadium, which explains the absence of hydrogen self-clustering from the experiments. To find the possible origin of hydrogen bubble in vanadium, we explored the minimum sizes of a vacancy cluster in vanadium for the formation of hydrogen molecule. We show that a freestanding hydrogen molecule can form and remain relatively stable in the center of a 54-hydrogen atom saturated 27-vacancy cluster.

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First-principles investigation on vacancy trapping behaviors of hydrogen in vanadium

Cited by 29 publications

References 41 publications

Development of tungsten-based materials by different sintering techniques

Development of tungsten-based materials by different sintering techniques

Hydrogen retention by vanadium-titanium alloys

Relationship between the Behavior of Hydrogen and Hydrogen Bubble Nucleation in Vanadium

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