Study on superplastic blow-forming in a rectangular closed-die

The objective of this paper is to explore the plastic deformation behavior of the sheet during blow-forming a superplastic sheet into a rectangular closed-die by the finite element method. A finite element commercial code “DEFORM” is used to carry out the simulations and calculate the pressurization profile and the sheet thickness distribution during the blow-forming process. A pressure control algorithm is proposed to keep the maximum strain rate in the deformation zone of the sheet equal to the target value, which corresponds to the highest m-value of the material being SPFed. The thickness distributions of the formed product using constant pressure control and keeping target strain rate control are compared. Experiments using 8090 Al–Li sheets on superplastic blow-forming in a rectangular closed-die are also carried out. The theoretical predictions of thickness distribution of the product are compared with experimental results.