SANS measurements of deuterium-dislocation trapping in deformed single crystal Pd

Heuser, Brent J.; King, John S.

doi:10.1016/s0925-8388(97)00211-9

Cited by 33 publications

(35 citation statements)

References 13 publications

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“…The resolution of the weak net SANS signals associated with trapped solutes requires the reduction or elimination of significant background contributions. In particular, the strong Porod scattering from internal interfaces [6] observed at low wave-vector transfer values (Q<0.03 Å -1 ) by Maxelon et al [5] is absent in our previous single crystal Pd SANS data [3,4] and in the measurements presented below. Strong low-Q Porod scattering from polycrystalline Pd was in fact observed prior to Maxelon et al and attributed to the presence of MnO inclusions imaged with transmission electron microscopy [7].…”

Section: Methodsmentioning

confidence: 48%

“…The Pd single crystal sample used here was taken from the same ingot described previously by Heuser and King [4]; complete details regarding the supplier and growth method of this ingot are contained in Reference 4. The resolution of the weak net SANS signals associated with trapped solutes requires the reduction or elimination of significant background contributions.…”

Section: Methodsmentioning

confidence: 99%

“…The deformed single crystal Pd sample used here had a [110] face normal (corresponding to the growth direction of the original ingot [4]), was 0.310 cm thick, had a diameter of approximately 1 cm, and a mass of 4.4681 g. This sample was first cold work to ~40% thickness reduction by cross rolling at room temperature. The sample was then further deformed by cycling across the hydride miscibility gap twice at room temperature, a process known to generate dislocation defects [3,4].…”

Section: Methodsmentioning

confidence: 99%

“…The sample was then further deformed by cycling across the hydride miscibility gap twice at room temperature, a process known to generate dislocation defects [3,4]. Representative transmission electron microscopy (TEM) images of Pd after cold working and cold working plus hydride cycling are shown in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

“…This work presented a fully-developed analytical cross section model, used single crystal Pd sample material and a hydride cycling procedure that were unique to the published literature at the time. A subsequent publication by Heuser and King [4] presented additional SANS measurements in which differences between cold worked and hydride cycled single crystal Pd were better resolved and analyzed. In the previous work by Heuser et al and by Heuser and King, as well as the current work, the solute-edge dislocation trapping interaction is assumed to be responsible for the SANS response.…”

Section: Introductionmentioning

confidence: 99%

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Small-angle neutron scattering measurements of hydrogen and deuterium trapping at dislocations in deformed single-crystalline Pd at low temperature

Heuser

2011

Phys. Rev. B

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Section: Methodsmentioning

confidence: 48%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Small-angle neutron scattering measurements of hydrogen and deuterium trapping at dislocations in deformed single-crystalline Pd at low temperature

Heuser

2011

Phys. Rev. B

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Hydrogen in Nano‐sized Metals

Pundt¹

2004

Adv Eng Mater

148

101

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Nano-sized metal systems have received growing attention during the last decade which is not only motivated by the technological interest in low-dimensional systems providing the size reduction of electronic devices, but also by fundamental interest since physical properties tend to show interesting changes when the size of the system is reduced. So called finite-size effects become relevant as soon as the system-size is in the order of the correlation length of the system. Surface-as well as interface-effects influence strongly the system behaviour when their relative fraction compared to the volume increases. Furthermore, often substrate contributions influence the system properties. All these contributions become more relevant when the system size goes down to the nanometer-range. This range is, especially with regard to applications, a major field of interest: low-dimensional patterning of electronic devices still can increase the information density or might reduce the size of the product of interest. On the other hand, surface related processes, for example catalysts demand for nano-sized materials providing a large amount of active surface area. Physical properties of these systems, for example phase boundaries and lattice structures, tend to be quite different from those of the large size ªbulkº system. Therefore, the understanding of general rules or trends occurring at minimisation of metal-systems is an important problem that still needs to be solved.Nano-sized metal systems are mostly found in the shape of thin films, rods or clusters. Also stacking of nano-sized systems in so-called multi-layers causes interesting sample morphologies with a high density of interface volume (see Fig. 1).The physical properties of such nano-sized systems can be studied by choosing systems with a highly mobile alloying partner: the metal-hydrogen systems. The big advantage of such a system is that alloying is possible just by increasing the partial hydrogen-gas pressure (or chemical potential). According to Sieverts the concentration c H (given by the number of H-atoms per metal-atoms H/M) inside a metal is connected with the gas-pressure p H2 expressed by the solubility S 0 , c H =S 0 Öp H2 . [1] This equation holds for the low-concentration-range for all metals at the most up to the concentration where a hydride is formed. This concentration is called the solubility limit. The solubility S 0 varies significantly, for example for bulk Yttrium (Y) or Niobium (Nb) it is up to 10 11 or 10 3 , respectively, down to small values of 10 ±1 for bulk Palladium (Pd) or 10 ±20 for Tungsten (W). This implies huge differences in the hydrogen concentration for different metals at the same hydrogen gas pressure (chemical potential). However, the solubility for the nano-sized system can be different compared to bulk.Because of its small size and its ability to tunnel between neighbouring interstitial lattice sites, hydrogen is highly mobile. Diffusion constants such as 3´10 ±7 cm 2 /s for Pd (at 300 K) are usual, resulting in diffusio...

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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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SANS measurements of deuterium-dislocation trapping in deformed single crystal Pd

Cited by 33 publications

References 13 publications

Small-angle neutron scattering measurements of hydrogen and deuterium trapping at dislocations in deformed single-crystalline Pd at low temperature

Small-angle neutron scattering measurements of hydrogen and deuterium trapping at dislocations in deformed single-crystalline Pd at low temperature

Hydrogen in Nano‐sized Metals

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

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