  Hydrogen embrittlement can cause a dramatic deterioration of the mechanical
properties of high-strength metallic materials. Despite decades of experimental
and modelling studies, the exact underlying mechanisms behind hydrogen
embrittlement remain elusive. To unlock understanding of the mechanism and
thereby help mitigate the influence of hydrogen and the associated
embrittlement, it is essential to examine the interactions of hydrogen with
structural defects such as grain boundaries, dislocations and stacking faults.
Atom probe tomography (APT) can, in principle, analyse hydrogen located
specifically at such microstructural features but faces strong challenges when
it comes to charging specimens with hydrogen or deuterium. Here, we describe
three different workflows enabling hydrogen/deuterium charging of site-specific
APT specimens: namely cathodic, plasma and gas charging. We discuss in detail
the caveats of the different approaches in order to help with future research
efforts and facilitate further studies of hydrogen in metals. Our study
demonstrates successful cathodic and gas charging, with the latter being more
promising for the analysis of the high-strength steels at the core of our work.
