Processing and mechanical properties of nanocrystalline 5083 Al alloy

A commercial aluminum alloy, 5083, was processed using a cryomilling synthesis approach to produce nanocrystalline powders. The powders were subsequently degassed, HIPped, and extruded to produce a thermally stable bulk nanocrystalline material. The grain size at each processing step was measured utilizing both X-ray diffraction and transmission electron microscopy. The mechanical properties of the n-5083 extruded material were determined utilizing ASTM E8-93, Standard Test Methods for Tension Testing of Metallic Materials. The nanocrystalline 5083 was found to have a 30% increase in yield strength and ultimate strength over the strongest commercially available form of 5083 with no corresponding decrease in elongation. Grain boundary sliding is proposed as a possible mechanism for the observed enhanced ductility.