Abstract
Nanostructured materials are of widespread interest because of the unique properties they offer. We have demonstrated that nanocrystalline 6061 and 5083 aluminum powders, prepared using liquid nitrogen (LN2) ball milling, can be consolidated using the cold spray process. TEM analysis of the cold spray coatings reveals that the cold spray process caused significant grain refinement. Gas atomized 6061 and 5083 aluminum powders were ball milled in liquid nitrogen resulting in a powder microstructure containing 250-400 nm grains. Cold spray coatings prepared using these feed stock materials exhibited homogenous microstructures with grain sizes of 30-50 nm. TEM analysis of the as-received powders, ball milled powders, and coatings are shown. Mechanical property measurements made using nano-indentation techniques show that the hardness of the coatings prepared using the LN2 ball milled 6061 is approximately double the hardness of the coatings prepared using the same powder in its as-received condition.
