Increase in dislocation density in cold-deformed Pd using H as a temporary alloying addition

Long-term hydrogen storage in Mg and ZK60 after Severe Plastic Deformation

“…The major part of these lattice defects associate with the Zn atoms and/or the precipitates and thus form atomic arrangements remaining stable even at elevated working temperatures. In all, a very high concentration of potential trapping sites for hydrogen atoms is available in the material in the form of defects generated by SPD [16,22,23], dissolved Zn atoms and precipitates (Zr atoms which are not associated with the MgZn 2 precipitates but are dissolved in the Mg lattice may have a similar effect as the dissolved Zn).…”

“…There, they will be readily trapped at SPD defects [16,22] stabilized by Zn atoms and acting as nucleation sites for the formation of the MgH 2 phase. As a rule, the grain size will be orders of magnitude larger than the average distance between neighboring nucleation sites.…”

“…Similar to ZK60, however, lattice defects such as vacancy agglomerates, dislocations and grain boundaries formed during SPD treatment will act as the principal nucleation sites [16,22]. Yet, unlike ZK60, these defects are not stabilized by impurity atoms so that, due to the comparably high working temperature during the cycling experiment, the number of defects is expected to rapidly diminish.…”

Materials and Corrosion Trends in Offshore and Subsea Oil and Gas Production

“…6, show that the required load for pop-in, i.e., homogeneous dislocation nucleation, is reduced in the presence of H. Additionally, the amount of the reduction in the pop-in load scales with the amount of hydrogen which is controlled by the applied electrochemical polarization. Per the defactant theory, [108][109][110][111] the decrease in the load required for dislocation nucleation can be related to the reduction in the dislocation line energy by H. 96,112,113 Hydrogen effects on crack propagation: microcantilever bending tests FIB cut micro-samples, loaded inside a nanoindenter equipped with special tips have traditionally been used to study size-effects in metals and alloys. [114][115][116][117][118] The possibility of in situ electrochemical H charging inside a nanoindenter provides a unique opportunity to perform such microscale experiments on Hcharged samples, Fig.…”

Hydrogen-induced defects and multiplication of dislocations in Palladium

“…In particular Fukai and Ō kuma [3] observed extraordinary high vacancy concentration in a Pd annealed at a high hydrogen pressure of 5 GPa. Cheng et al [4] found that the dislocation density in a cold rolled Pd-H is remarkably enhanced compared to a pure Pd subjected to the same deformation. The enhancement of the defect density in Pd containing hydrogen can be understood in the terms of reduction of the defect formation energies by segregating hydrogen proposed by Kirchheim [5].…”