Fabrication of surface nanocrystalline aluminum alloys

In the present study, the authors aimed to fabricate surface nanocrystalline aluminum alloys by severe plastic deformation. The surface of the various kinds of aluminum alloy sheets were stirred and highly strained by wire-brushing at ambient temperature. The process was applied to 99.99wt.%Al, commercial purity aluminum (1050 and 1100), Al-Mg alloy (5083) and Al-4wt.%Cu alloy. In all the wire-brushed aluminum alloys, nearly equiaxed nanocrystals with grain sizes ranging from 60 nm to 200 nm were observed at surface regions. In case of the 1050-H24 aluminum, the depth of the surface nanocrystalline layer is about 15 μm. The wire-brushed sheet of 1100-O 1 mm thick with the surface nanocrystalline structure performed the 0.2% proof stress 1.5 times higher than that of the starting sheet.