Metallography of the niobium hydrogen system

Schober, T.; Linke, U.; Wenzl, H.

doi:10.1016/0036-9748(74)90299-3

Cited by 17 publications

(8 citation statements)

References 11 publications

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“…I n complete agreement with a recent metallographic study [14], it was found that rooin temperature electrolytic charging led to irregularly shaped P-hydride particles with dendritic features. Charging at 150 "C produced some dendritic hydrogen precipitates, but mainly plates of the P-hydride phase on {loo}.…”

Section: /3-phase Precipitation After Electrolytic Hydrogen Chargingsupporting

confidence: 90%

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The niobium-hydrogen system – an electron microscope study. I. Room temperature results

Schober

1975

Phys. Stat. Sol. (a)

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The room temperature morphology of @and &phase precipitation in the NbH system is investigated under ultrahigh purity conditions (UHV degassed Nb and electrolytic charging). The P-phase (NbHo.7 in the two phase region) precipitated after electrolytic charging at room temperature in the form of large, dendritic particles. Charging at 150 "C mainly results in plates on { 100). The presence of domain boundaries, antiphase boundaries, and twins in such precipitates is demonstrated. Evidence for extensive plastic deformation in P-phase areas is obtained and possible reasons for this are discussed. &phase (f.c.c. NbH,) precipitation occurs in the form of plates on { 210) inside the @-phase. Observations are presented on the Pand &phase morphology for concentrations of up to 200% (= H/Nb).The main reasons for hydrogen embrittlement in highly charged NbH samples are described. Die Morphologie von Pund 6-Phasen-Ausscheidung bei Zimmertemperatur im NbH-System wurde unter Bedingungen hochster Reinheit untersucht (mit UHV entgastem Nb und elektrolytischer Beladung). Die @-Phase (NbHo.7 im Zweiphasengebiet) wird nach elektrolytischer Beladung bei Zimmertemperatur in Form groSer, dendritisoher Teilchen ausgeschieden. Nach Beladung bei 150 OC! werden hauptsiichlich Platten auf < 100) erhalten. Es wird das Auftreten von Domiinengrenzen, Antiphasengrenzen und Zwillingen in solchen Ausscheidungen gezeigt. Gebiete der P-Phase zeigen Spuren starker plastischer Verformung. Mogliche Griinde dafur werden diskutiert. Die Ausscheidung der &Phase (k.f.z. NbH,) erfolgt in Form von Platten auf { 210) innerhalb der P-Phase. Beobachtungen der Morphologie von Pund 8-Phasen werden fur Konzentrationen bis 200% (= H/Nb) beschrieben. Es werden die Hauptgrunde fur die Wasserstoff-Versprodung in hochdotierten NbH-Proben angefiihrt.

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Section: /3-phase Precipitation After Electrolytic Hydrogen Chargingsupporting

confidence: 90%

“…8 b illustrates precipitation on { 100) (details in figure caption). A twosurface trace analysis showed the %phase plates to lie on { 210) planes, which is identical with the habit plane of the &phase as determined in a recent metallographic study [14]. I n Fig.…”

Section: Andphase Precipitationsupporting

confidence: 83%

The niobium-hydrogen system – an electron microscope study. I. Room temperature results

Schober

1975

Phys. Stat. Sol. (a)

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“…The hydrogen atoms occupy the tetrahedral positions leading to a stoichiometry close to NbH x where 0.7 b x b 1.1 [7,10]. This phase is normally designated as niobium hydride and it is extremely brittle.…”

Section: Introductionmentioning

confidence: 99%

“…In this process, the embrittlement of the metal is promoted through hydrogen dissolution in interstitial sites of the bcc structure forming brittle hydrides [1][2][3][4][5][6][7]. Through mechanical milling, the material is reduced to the powdered form.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of thermal decomposition of niobium hydride

Gabriel

Brum

Candioto

et al. 2012

International Journal of Refractory Metals and Hard Materials

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“…When the concentration of the dissolved hydrogen reaches the solubility limit, the hydride precipitates with xp = 0.7 (P-phase). Large incoherent (100) plates are to appear if the phase separation is being slowly performed [7]. At temperature below 200 K the low temperature phase with long-range order of hydrogen interstitials occurs (€-phase).…”

Section: Introductionmentioning

confidence: 99%

Direct Observation of Magnetic Structure in Niobium Single Crystals with Hydride Precipitate Pinning Centres

Golubok

1982

phys. stat. sol. (a)

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The high resolution direct observation of the Nb single crystal magnetic structure due to hydride precipitate pinning centers is presented. The magnetic structure is studied by depositing ferromagnetic particles on a sample surface in magnetic field (H = 0 → 6000 Oe → 250 Oe) perpendicular to the {100} and {110} planes. The Bitter patterns obtained are observed with a scanning electron microscope.

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Metallography of the niobium hydrogen system

Cited by 17 publications

References 11 publications

The niobium-hydrogen system – an electron microscope study. I. Room temperature results

The niobium-hydrogen system – an electron microscope study. I. Room temperature results

Kinetics of thermal decomposition of niobium hydride

Direct Observation of Magnetic Structure in Niobium Single Crystals with Hydride Precipitate Pinning Centres

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