Finite Element Modeling of Superplastic Forming in the Presence of Back Pressure

Abstract

It is established that some superplastic materials undergo significant cavitation during deformation. Cavitation not only limits the superplastic ductility of the material, but also reduces the service properties and the fatigue performance of the formed parts. Experimental results have shown that an effective method to eliminate cavitation is the application of hydrostatic pressure during deformation. In this work, finite element simulations are carried out to study the effects of hydrostatic pressure on damage evolution during SPF. The analysis is conducted for the superplastic copper based alloy Coronze-638 at 550 °C. The results clearly demonstrate the effectiveness of the superimposition of hydrostatic pressure in reducing the amount of cavities generated during SPF and improving the integrity of the formed part.