  Metal powders with hierarchical nanostructures are always designed and
fabricated by dealloying with or without combination of other manufacturing
processes. However, they are mainly nanoporous metal powder and its
derivations, and their monotonous nanostructures restrict their applications,
so metal powders with novel nanostructures should be explored further for
various applications. Herein, high energy mechanical milling and dealloying can
be combined together for fabricating mass-produced metal powders with
controllable nanostructures. As an example, a nanograins-attached and ultrathin
Cu flake powder can be fabricated by high energy mechanical milling of a
Cu-42wt.%Al powder mixture and subsequent dealloying. The dealloyed Cu powder
particles have ultrathin flaky shapes with numerous Cu grains being attached to
their surfaces, and the microstructure of the as-milled Cu-42wt.%Al powder
particles and the dealloyed Cu particles is studied to elucidate the formation
mechanism of the unique morphology of the dealloyed Cu powder.
