The Numerical Analysis on Superplastic Forming under Plane Strain for 7475 Al-Alloy

Abstract

The numerical analysis on superplastic forming under plane strain was put in operation. This analytical method is able to account for the strain hardening with regard to strain rate of formed material. The strain rates of each element laid out on the formed material are determined by the combination of stress and strain which are provided by the theoretical equations and stress-strain curve on the tensile test under some strain rates. The experiment was carried out with the condition calculated by the analytical method on the corrugated die for 7475 Al-alloy. The deformation process and variation of thickness on the rectangular pan formed by optimum condition was good agreement with the result predicted by the calculation. By using this analytical method, superplastic forming of the rectangular pan which was controlled the thickness variation to 1: 2 on wall and bottom was planed. The thickness of blank sheet was machined locally according to the design by analysis. It was formed to the rectangular pan successfully. and the formed pan had the thickness distribution which was intended on the forming plan.