Journal ArticleDOI
The Effect of Hydrogen on the Deformation and Fracture of Polycrystalline Nickel
A. H. Windle,G. C. Smith +1 more
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In this paper, a polycrystalline nickel (grain size 140 μm) containing 9 ppm hydrogen has been mechanically tested over the range − 196 to + 100° C (77 to 373K) and at strain rates from 0·1 to 0·0001 s−1.Abstract:
Polycrystalline nickel (grain size 140 μm) containing 9 ppm hydrogen has been mechanically tested over the range − 196 to + 100° C (77 to 373K) and at strain rates from 0·1 to 0·0001 s−1. The hydrogen causes serrated yielding between − 130 and − 30° C (145 and 245 K), an increase in work-hardening rate between − 160 and + 100° C (115 and 373K), but no increase in yield stress. Hydrogen also weakens the nickel grain boundaries under all testing conditions. The resultant intergranular embrittlement is most marked below − 50° C (225 K) and appears to be enhanced by the occurrence of serrated yielding and grain-boundary shears. It is suggested that a very thin layer of hydride weakens the grain boundaries, but there is no direct evidence to support this.read more
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Journal ArticleDOI
Hydrogen embrittlement of metals
TL;DR: The deleterious effects of hydrogen on the tensile properties of metals are caused by the association and movement of hydrogen with dislocations as discussed by the authors, and hydrogen-dislocation interactions modify plastic deformation processes by stabilizing microcracks, by changing the work hardening rate, and by solid solution hardening.
Journal ArticleDOI
Hydrogen transport by dislocations
TL;DR: In this article, a kinetic model for the transport of hydrogen, as Cottrell atmospheres on dislocation, at a rate appreciably in excess of that for lattice diffusion is presented.
Journal ArticleDOI
Mechanism of Work Hardening in Hadfield Manganese Steel.
Y. N. Dastur,W. C. Leslie +1 more
TL;DR: In this article, a single-phase austenitic condition was studied and the apparent activation energies for the appearance and disappearance of serrations were found to be 104 and 146 kJ/mol, respectively, for static strain aging between 300 and 400 °C.
Journal ArticleDOI
An HVEM study of hydrogen effects on the deformation and fracture of nickel
Ian M. Robertson,H.K. Birnbaum +1 more
TL;DR: In this article, the authors investigated the mechanisms of hydrogen "embrittlement" of nickel by performing in situ straining experiments in a highvoltage electron microscope equipped with an environmental cell.
Journal ArticleDOI
On the effect of hydrogen on plastic instabilities in metals
TL;DR: In this paper, a theoretical investigation is carried out in a specimen under plane-strain tension in an effort to understand how hydrogen-induced softening and lattice dilatation at the microscale can lead to macroscopic i) shear localization (shear banding bifurcation) or ii) necking bivurcation.
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Journal ArticleDOI
The influence of hydrogen on the plastic deformation ductility, and fracture of nickel in tension
T Boniszewski,G.C Smith +1 more
TL;DR: The maximum binding energy of a hydrogen atom and a dislocation in nickel has been found to be about 0.08 eV, and the diffusion of hydrogen to dislocations occurs with an activation energy 8.2-9.3 kcal/mole.
Journal ArticleDOI
Intercrystalline fracture in hydrogen-charged nickel
B.A Wilcox,G.C Smith +1 more
TL;DR: In this article, it is suggested that hydrogen pressure builds up in propagating microcracks and aids the applied stress in the fracturing process, and also that the rate of crack propagation may be a hydrogen diffusion controlled process.
Journal ArticleDOI
The Portevin-Le Chatelier effect in hydrogen charged nickel
B.A Wilcox,G.C Smith +1 more
TL;DR: In this article, the authors investigated the effect of the Portevin-Le Chatelier effect on serrated yielding in hydrogen charged polycrystalline nickel (6.1 cc H 2 100 g Ni ) tested in tension at −80°C.
Journal ArticleDOI
The Effect of Hydrogen on the Plastic Deformation of Nickel Single Crystals
A. H. Windle,G. C. Smith +1 more
TL;DR: In this article, it is suggested that hydrogen can lower the stacking-fault energy of nickel from 240 to 155ergs, but has no effect on the critical resolved shear stress at any temperature.
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