Abstract
This work describes recent progress in cold spray deposition of nanocrystalline metals and alloy. Gas-atomized powders (Ni and Aluminum alloys powder) were mechanically milled under liquid nitrogen to achieve a nanocrystalline grain size of the order of 10-30 nm. The powders were subsequently sprayed using a nozzle designed with a validated numerical model for cold spray technology. The resulting coatings were evaluated using scanning electron microscopy (SEM), transmission electron microscopy (TEM), micro- and nanoindentation. TEM analysis shows that the nanocrystalline grain structure of the cryomilled feedstock powder was retained after the cold spray process. A significant increase in hardness was observed for all the cryomilled material when comparing with the conventional gas-atomized powder. The ability to use cold spray to produce nanocrystalline large deposits with low porosity (<1%) was also demonstrated in this work. Abstract only; no full-text paper available.
