  Measuring local chemistry of specific crystallographic features by atom probe
tomography (APT) is facilitated by using transmission Kikuchi diffraction (TKD)
to help position them sufficiently close to the apex of the needle-shaped
specimen. However, possible structural damage associated to the energetic
electrons used to perform TKD is rarely considered and is hence not
well-understood. Here, in two case studies, we evidence damage in APT specimens
from TKD mapping. First, we analyze a solid solution, metastable
\b{eta}-Ti-12Mo alloy, in which the Mo is expected to be homogenously
distributed. Following TKD, APT reveals a planar segregation of Mo amongst
other elements. Second, specimens were prepared near {\Sigma}3 twin boundaries
in a high manganese twinning-induced plasticity steel, and subsequently charged
with deuterium gas. Beyond a similar planar segregation, voids containing a
high concentration of deuterium, i.e. bubbles, are detected in the specimen on
which TKD was performed. Both examples showcase damage from TKD mapping leading
to artefacts in the compositional distribution of solutes. We propose that the
structural damage is created by surface species, including H and C, subjected
to recoil from incoming energetic electrons during mapping, thereby getting
implanted and causing cascades of structural damage in the sample.
