STTR Friction Stir Processing for Superplastic Forming

Friction Stir Processing (FSP) is an emerging technology that can be used to pre or post-process a range of materials, including aluminum, to locally modify material properties. It is known that FSP can be used to enhance material properties for improved superplastic forming (SPF) behavior of aluminum. This can potentially allow for dramatic cost reductions of SPF and aluminum fabrications, allowing the combination to be viable in applications where previously they were not viable. To-date, many fabricated components have excluded use of aluminum for several reasons, including poor formability, difficulty joining, and significant distortion, increasing cost and complexity in applications where aluminum might be considered. This technology combination can eliminate these problems. The project discussed in this proposal aims to determine feasibility of FSP in combination with SPF in Naval applications. Both commercial and technical feasibility will be determined, with the objective of obtaining knowledge of when and which applications this technology is feasible. The commercial feasibility will involve investigations of potential applications to determine the characteristics that allow for commercial feasibility. An application will then be selected for which technical feasibility will be determined. This will involve a coupon level investigation which will demonstrate technical feasibility for the application. BENEFITS: It is anticipated that there will be a significant number of benefits related to the implementation of friction stir processing in combination with superplastic forming. These would include but not be limited to 1) Allowing aluminum to be used in a cost-effective manner where it has been previously deemed uncompetitive 2) Allowing for weight reduction. 3) Allowing for more complex shapes to be formed in aluminum, subsequently causing a a) Reduction in number of components b) Reduction of amount of joining, specifically welding and riveting c) Reduction in distortion d) Improved quality e) Ability to fabricate shapes not previously manufacturable. f) And ultimately lowering cost. There are numerous potential commercial applications for friction stir processing in combination with superplastic forming. These applications would typically benefit from aluminum's lightweight properties, but aluminum has not been used due to the limitations and cost of implementing aluminum into a fabrication. There are applications throughout the transportation industry and the military. In the Navy, doors, hatches, pallets, carts, and complex superstructure sub-assemblies could be considered. In land transportation, doors, frames, and body panels are applications of interest. In addition, general industry could also have applications. Multi-sided aluminum enclosures would be of specific interest, where these fabrications are currently made of numerous parts and part consolidation could be achieved with this technology.