Anisotropic Strain Enhanced Hydrogen Solubility in bcc Metals: The Independence on the Sign of Strain

Zhou, Hong-Bo; Jin, Shuo; Zhang, Ying; Lu, Guang Hong; Liu, Feng

doi:10.1103/physrevlett.109.135502

Cited by 113 publications

(55 citation statements)

References 30 publications

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“…21 On the other hand, the anisotropic strain is shown to enhance hydrogen solubility which helps the hydrogen bubble growth. 22 It is known that the equilibrium vacancy concentration in tungsten is as low as 10 −4 even at the melting point. 23 However, the phenomena of hydrogen blistering is indeed observed at the surface of single crystal tungsten under high flux irradiation with quite low energy (not larger than 100 eV).…”

Section: Introductionmentioning

confidence: 99%

Mechanism of vacancy formation induced by hydrogen in tungsten

et al. 2013

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We report a hydrogen induced vacancy formation mechanism in tungsten based on classical molecular dynamics simulations. We demonstrate the vacancy formation in tungsten due to the presence of hydrogen associated directly with a stable hexagonal self-interstitial cluster as well as a linear crowdion. The stability of different self-interstitial structures has been further studied and it is particularly shown that hydrogen plays a crucial role in determining the configuration of SIAs, in which the hexagonal cluster structure is preferred. Energetic analysis has been carried out to prove that the formation of SIA clusters facilitates the formation of vacancies. Such a mechanism contributes to the understanding of the early stage of the hydrogen blistering in tungsten under a fusion reactor environment.

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Section: Introductionmentioning

confidence: 99%

Mechanism of vacancy formation induced by hydrogen in tungsten

et al. 2013

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“…1b). Being smaller than the interstitial volume, H is not expected to yield substantial strain energy difference between the T and O sites [11]. Thus the result suggests that there is more to H trapping than a simple consideration of size effect.…”

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confidence: 89%

“…The insight gained from this study is expected to have important implications for the design of H storage and H-resistant materials. Interaction between H and lattice defects underlies diverse materials phenomena [1][2][3][4], including H storage [3,5], H embrittlement [6][7][8], metallic H membranes [9], nuclear fusion reactors [10,11] and H-assisted superabundant vacancy formation in metals [1,12,13], etc, to name a few. Crucial to all these problems is trapping of H at the lattice defects, such as vacancies, voids, dislocations, grain boundaries and cracks [14][15][16][17][18][19][20][21][22].…”

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confidence: 99%

Unified mechanism for hydrogen trapping at metal vacancies

Xing

Chen

Xie

et al. 2014

International Journal of Hydrogen Energy

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Interaction between hydrogen (H) and metals is central to many materials problems of scientific and technological importance. Chief among them is the development of H storage and H-resistant materials. H segregation or trapping at lattice defects, including vacancies, dislocations, grain boundaries, etc, plays a crucial role in determining the properties of these materials. Here, through first-principles simulations, we propose a unified mechanism involving charge transfer induced strain destabilization to understand H segregation behavior at vacancies. We discover that H prefers to occupy interstitials with high pre-existing charge densities and the availability of such interstitials sets the limit on H trapping capacity at a vacancy. Once the maximum H capacity is reached, the dominant charge donors switch from the nearest-neighbor (NN) to the next-nearest-neighbor (NNN) metal atoms. Accompanying with this long-range charge transfer, a significant reorganization energy would occur, leading to instability of the H-vacancy complex. The physical picture unveiled here appears universal across the BCC series and is believed to be relevant to other metals/defects as well. The insight gained from this study is expected to have important implications for the design of H storage and H-resistant materials. Interaction between H and lattice defects underlies diverse materials phenomena [1][2][3][4], including H storage [3,5], H embrittlement [6][7][8], metallic H membranes [9], nuclear fusion reactors [10,11] and H-assisted superabundant vacancy formation in metals [1,12,13], etc, to name a few. Crucial to all these problems is trapping of H at the lattice defects, such as vacancies, voids, dislocations, grain boundaries and cracks [14][15][16][17][18][19][20][21][22]. In particular, H trapping at vacancies has attracted the most attention thanks to the facts that (1) vacancies are easier to study than other defects but have profound influences on materials properties; (2) vacancies hold many surprises and mysteries yet to be explored; (3) the insight gained from vacancies can be applied to other defects as well.It is found that for BCC and FCC metals, up to six H atoms can be trapped by a monovacancy in general because H prefers to occupy the six octahedral (O) interstitials surrounding the vacancy [1,16,17]. However, there are exceptions -the maximum H capacity can go up to 10 for Molybdenum (Mo) [16,17,23] and 12 for Tungsten (W) and Aluminum (Al) [14]. Different interpretations of the available experimental results have also been put forward: (i) The competition between metal-H hybridization and the Coulombic repulsion determines the position and number of H atoms at the vacancy in BCC-Fe [24]; (ii) Comparing to Fe, the greater H trapping capacity in Al is attributed to a larger lattice constant and more delocalized electronic states [14]; (iii) In W, it is found that the vacancy provides an isosurface of optimal charge density that facilities the formation of H bubbles [25]. Clearly, an important question to ask is ...

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“…Much recent efforts have been devoted to understanding the interaction of H with W between experiment [3][4][5][6][7] and simulation [8][9][10][11][12][13][14][15][16][17][18][19]. We know that the implanted H ions can easily diffuse into the inner of metal and they will eventually find the suitable trapping sites and collect [20,21], leading to the nucleation and growth of H blistering [22,23].…”

Section: Introductionmentioning

confidence: 97%