Rate-depending plastic deformation behaviour in a nickel-base alloy under hydrogen influence

Despite a lot of research activities, the influence of hydrogen on the plastic deformation process is controversially discussed and often underestimated. Therefore, in this work strain rate jump tests were performed, using an electrochemical nanoindentation setup to investigate the deformation processes in a nickel-based alloy 725 under the influence of hydrogen, with the aim of determining thermally activated parameters such as strain rate sensitivity and activation volume. A hydrogen-induced hardness increase of about 8% was detected for all applied strain rates. The measured increase in strain rate sensitivity and the decrease in activation volume could be related to short-range order effects, which can lead to a more localized deformation. Furthermore, the optical evaluation of the remaining imprints showed a clear change in the formation of the plastically deformed zone during hydrogen charging. These insights into the deformation behaviour give further understanding regarding hydrogen-induced localized plasticity. (c) 2021 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Through strain rate jump tests, it was found that the influence of hydrogen can lead to an increase in hardness, an increase in strain rate sensitivity, a decrease in activation volume, and a change in the formation of plastically deformed zone in nickel-based alloy 725, further study contributes to understanding hydrogen-induced localized plasticity.