Effect of dislocation trapping on deuterium diffusion in deformed, single-crystal Pd

Heuser, Brent J.; King, John S.

doi:10.1007/s11661-998-0083-4

Cited by 11 publications

(6 citation statements)

References 14 publications

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“…In the deformed structure, there is a very high dislocation density, and these dislocations act as efficient traps for hydrogen [28][29][30]. Additionally, the fibrous structure in the heavily cold-worked material contributes to a large new grain boundary/sub-grain boundary area, and thus provides a large number of boundary traps for capturing diffusive hydrogen atoms.…”

Section: Discussionmentioning

confidence: 99%

Influence of processing conditions on the microstructure and permeability of BCC V–Ni membranes

Song

Kellam

Liang

et al. 2010

Journal of Membrane Science

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Section: Discussionmentioning

confidence: 99%

Influence of processing conditions on the microstructure and permeability of BCC V–Ni membranes

Song

Kellam

Liang

et al. 2010

Journal of Membrane Science

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“…Small angle neutron scattering measurements of deuterium dislocation trapping in Pd have recognized rod-like trapping geometry [16], as well as that dislocations in H(D)-cycled Pd can absorb large amount of hydrogen (deuterium) [17]. Anomalies in the electron transport and magnetic properties in a deformed loaded Pd foil were interpreted in terms of filamentary superconductivity attributed with the condensation of the trapped hydrogen (deuterium) into a metallic-like phase (∼ 10 24 cm −3 ) within the dislocation core [18].…”

Section: Introductionmentioning

confidence: 99%

Warm Dense Matter Generation and DD Synthesis at Vacuum Discharge with Deuterium‐Loaded Pd Anode

Kurilenkov

Тараканов

Gus’kov

et al. 2011

Contrib. Plasma Phys.

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The energetic ions and DD neutrons from microfusion at the interelectrode space of a low energy nanosecond vacuum discharge with deuterium-loaded Pd anode has been demonstrated recently. To understand better the physics of fusion processes the detailed PIC simulation of the discharge experimental conditions have been developed using a fully electrodynamic code KARAT. The dynamics of main charge particle species was reconstructed in time and interelectrode space. The principal role of a virtual cathode (VC) and the corresponding single and double potential well formed in the interelectrode space are recognised. The calculated depth ϕ of the quasistationary potential well (PW) of the VC is about 50-60 kV, and the D + ions being trapped by this well accelerate up to energy values needed to provide collisional DD nuclear synthesis. Both experiment and PIC simulations illustrate very favourable scaling of the fusion power density at decreasing of VC radius ( ∼ ϕ 2 /r 4 V C ) for the chosen inertial electrostatic confinement fusion scheme based on miniature nanosecond vacuum discharge. Meanwhile, the initial stage of discharge is understood still poorly. When voltage is applied, the electron beam extracted from cathode starts to interact with the surface of deuterium-loaded Pd anode. This early stage of discharge manifests sometime the peaks registered by photomultipliers which are similar to neutron ones from time-of-flight measure under the study of collisional DD synthesis at the further stages of discharge. The detailed study of Pd anode surface morphology have been performed and recognized, in particular, the number of various pores and craters of different sizes. We remark that besides of rather usual craters (due to electron beams -anode interaction) some of the craters on the Pd anode surface may correspond to anode ectons (explosive centres) and consider their possible nature. Specifics of warm dense matter (WDM) generated at different stage of discharge is discussed. The data obtained are compared with recent results on initiation of DD reactions by electron beams at deuterium -loaded Pd foils and correspondent data on their surface morphology.

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“…This is due to the strong interactions of dislocations and hydrogen, 12 with a binding energy of 0.2eV. 13 To determine the effect of the dislocation core on hydrogen vibration spectra, we compute the anharmonic H potential energy adjacent to a dislocation core from first-principles, and calculate excitation energies and wavefunctions. The result is a decrease in excitation energy consistent with experiments and distortions in the hydrogen wavefunctions due to strain and symmetry breaking.…”

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confidence: 99%

First-principles calculation of H vibrational excitations at a dislocation core of Pd

Lawler

Trinkle

2010

Phys. Rev. B

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Palladium is an ideal system for understanding the behavior of hydrogen in metals. In Pd, H is located both in octahedral sites and in dislocation cores, which act as nanoscale H traps and form Cottrell atmospheres. Adjacent to a dislocation core, H experiences the largest possible distortion in α-Pd. Ab initio density-functional theory computes the potential energy for a hydrogen in an octahedral site in α-Pd and in a trap site at the core of a partial of an edge dislocation. The Pd partial dislocation core changes the environment for H, distorting the H-Pd bonding which changes the local potential, vibrational spectra, and inelastic form factor for an isolated H atom. The decrease in excitation energy is consistent with experiments, and the calculations predict distortions to the H wavefunction.1 Renewable energy requires new methods for the production, storage and transportation of energy from the point of production. The potential for hydrogen as an energy storage medium 1 has renewed interest in the fundamentals of hydrogen in metals-a topic with a long history. 2 In particular, the ease of catalysis of molecular to atomic hydrogen on the surface of palladium has motivated the study of atomic hydrogen and hydride formation in Pd. Hydrogen's vibrational excitations in metals provide an interesting window into H behavior due to its low mass; and α-Pd is a useful system to consider as a model system that is simple to prepare. 3 There are various means of measuring the vibrational energies, such as conductance spectroscopy, 4 Raman scattering, 5 and inelastic neutron scattering. 6 Neutron scattering measured isotopic effects, 7 linewidths and their dependence on temperature, 8 the optical band and its high-energy features, 9 and concentration dependence of the spectra. 10 Heuser et al. recently measured the hydrogen excitation peak at 4K to be 59meV for the dilute (0.08at.%) H concentration, while at 300K the peak was 68meV. 11 The low concentration suggests hydrogen trapped at edge-dislocation core interstitial sites. This is due to the strong interactions of dislocations and hydrogen, 12 with a binding energy of 0.2eV. 13To determine the effect of the dislocation core on hydrogen vibration spectra, we compute the anharmonic H potential energy adjacent to a dislocation core from first-principles, and calculate excitation energies and wavefunctions. The result is a decrease in excitation energy consistent with experiments and distortions in the hydrogen wavefunctions due to strain and symmetry breaking. ACKNOWLEDGMENTS See the EPAPS homepage for more information. 28 X. Ke and G. J. Kramer, Phys. Rev. B, 66, 184304 (2002).8 TABLE I. Calculated and measured transition energies for H in α-Pd and adjacent to a partial dislocation core. Hydrogen occupies an octahedral site in α-Pd; the transition from the ground state to the triplydegenerate first excited state is larger than the experimentally measured peak. A volumetric expansion of 5% reduces the predicted transition energy by 9meV. The partial dislocation core pr...

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Effect of dislocation trapping on deuterium diffusion in deformed, single-crystal Pd

Cited by 11 publications

References 14 publications

Influence of processing conditions on the microstructure and permeability of BCC V–Ni membranes

Influence of processing conditions on the microstructure and permeability of BCC V–Ni membranes

Warm Dense Matter Generation and DD Synthesis at Vacuum Discharge with Deuterium‐Loaded Pd Anode

First-principles calculation of H vibrational excitations at a dislocation core of Pd

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