Modelling and tracing the super plastic deformation process of 7075aluminium alloy sheet: use of finite element technique

Super plastic forming (SPF) is a manufacturing process whereby certain materials under the correct conditions exhibit a large deformation without failure. In this field the existing analytical theory is far from perfect and the results deduced from it do not describe the real condition very well. Therefore numerical and modelling procedures are essential. In this study, a systematic approach was developed to control the variation in thickness of the product by carrying out forming analysis at constant strain rate. In this approach, experimentally determined material properties data at 525 °C temperature and at different cross-head speeds were used to model and analyse processes at constant strain rates. This was preceded by writing software using a parametric design language (PDL) to direct the flow of the analysis. Uniaxial tension and deep drawing processes for 7075 Al. alloy sheet were modelled and analysed. The results showed the effectiveness of this approach in describing the super plastic forming process at predefined process conditions and in tracing and controlling the variation in product thickness. Furthermore, it is established that in using this systematic approach, it is possible to allocate the proper process condition parallel with the complexity of the product.