  Atom probe tomography (APT) is extensively used to measure the local
chemistry of materials. Site-specific preparation via a focused ion beam (FIB)
is routinely implemented to fabricate needle-shaped specimens with an end
radius in the range of 50 nm. This preparation route is sometimes supplemented
by transmission Kikuchi diffraction (TKD) to facilitate the positioning of a
region of interest sufficiently close to the apex. Irradiating the specimen
with energetic electrons and ions can lead to the generation of vacancies and
even amorphization of the specimen. These extrinsically created vacancies
become crucial for probing the hydrogen or deuterium distribution since they
act as a strong trap. Here, we investigated the feasibility of site-specific
preparation of a two-phase medium-Mn steel containing austenite (fcc) and
ferrite (bcc). Following gaseous charging of APT specimens in deuterium (D2),
clusters enriched by up to 35 at.% D, are imaged after Pt deposition,
conventional Ga-FIB preparation, and TKD conducted separately. These D-rich
clusters are assumed to arise from the agglomeration of vacancies acting as
strong traps. By systematically eliminating these preparation-induced damages,
we finally introduce a workflow allowing for studying intrinsic traps for H/D
inherent to the material.
