Finite element simulation of selective superplastic forming of friction stir processed 7075 Al alloy

For many superplastically formed components, only some regions undergo superplastic deformation. In these cases, instead of choosing expensive starting sheet material with superplastic properties, a low-cost, conventional material can be chosen and friction stir processing (FSP) can be performed in the selected regions to impart superplastic properties locally. This is called “selective superplastic forming” [R.S. Mishra, M.W. Mahoney, US Patent 6,712,916, 2002]. In this study, finite element simulation of superplastic forming of a bowl shape component with inhomogeneous properties has been conducted. We chose commercial 7075 Al alloy as the starting material and FSP was used to generate fine grains in some regions. The pressure schedule, the overall forming time and the final thickness distribution in the formed component were calculated. This simulation demonstrates the design possibilities with this new concept.