Fabrication of High-Strength Nanostructured Bulk Aluminum Alloys

There is a need for better lightweight metal alloys for Department of Defense transportation vehicles. Such material will have extremely high strength and toughness, and could be used for improved armor and other vehicular structural components. We propose to fabricate three advanced extremely high strength aluminum alloys to address the need. To do this we will fabricate aluminum-manganese (Al-Mn), Al-zirconium (Al-Zr), and Al-Mn-Zr alloy powders by ball milling elemental powders to give grain sizes below 20 nm in the alloy. The alloy powders will then be consolidated by warm extrusion or spark plasma sintering or a combination of both, to bulk material with a grain size below 20 nm. The resulting materials are expected to have hardness above 3 GPa, a tensile ductility above 10 % elongation, and thermal stability to 330C. The alloy fabrication and processing parameters are expected to allow for scale-up to prototype size components with favorable economics for commercial manufacture.