Characterization of Nanocrystalline Aluminum Alloy 5083 Powders Produced by Cryogenic Attrition.

摘要

Cryomilling, the mechanical attrition of powders with milling balls at cryogenic environment and temperatures, was used to nanostructure AA5083 through grain size refinement. If the current military vehicle protective structures can be replaced with stronger cryomilled nanostructure AA5083, the vehicles will have significantly lowered weight and be highly fuel efficient. Cryomilling was completed for 8-, 16-, and 24-h periods to refine the grain size of AA5083 powder. Scanning electron microscopy revealed the morphology of the agglomerates. X-ray diffraction (XRD) was used to investigate the degree of grain size refinement and the phase purity. Gas fusion analysis, through the Leco system, was utilized in identifying how much oxygen, hydrogen, and nitrogen are in the cryomilled samples. There were no noticeable differences in agglomerate size and shape among the cryomilled powders with varying milling time. The XRD data showed that there was significant grain size refinement without detectable contamination.