Speaker
Description
Nanocrystalline (NC) Pd-Au prepared by inert gas condensation exhibits
fractal abnormal grain growth during heat treatment. The resulting
microstructure is characterized by a bimodal grain size distribution
with micrometer-sized grains (FG) embedded in a matrix of NC
grains (NG). To elucidate this unusual manifestation of grain growth,
we analyzed FG and NG bulk regions, as well
as the FG-FG and FG-NG interface regions with APT. The NG region exhibited an O
content that was multiple times higher in comparison with the FG region.
Cluster analysis confirmed the presence of a multitude of O-rich
clusters in the NG, but not in the FG region. Furthermore, the reconstructions
of the boundary regions revealed an unexpected diversity
of host and contamination element distributions at the FG-FG and
FG-NG interfaces.
