Optimizing the Superplastic Forming of Friction Stir Processed 7075 – T651 Aluminum Alloy through Finite Element Analysis

Abstract

The use of heat treatable 7075 aluminum alloys for the components of aerospace and aircraft industries are more common today .Aluminum alloys have many attractive advantages and properties which are more favorable to the fabrication of components and parts with greater flexibility. Superplastic forming (SPF) is a near net-shape forming process which is being used in aircraft industries for around thirty years in the fabrication of aluminium alloys in to aircraft structures and components .The process has many attractive advantages towards conventional forming techniques.Eventhough it has many advantages due to certain disadvantages like low forming rate , high working temperatures and high process cost. This has made the process not to be adopted in mass production scenarios in the industries. In the present study commercially available AA 7075 – T651 aluminum alloy is selected as the starting material and friction stir process is conducted at selective regions to alter the microstructure of the material to make it suitable for SPF. The material is further subjected to superplastic forming in to a bowel shape with inhomogeneous properties .Recent advancements in finite element tools have helped in the analysis of complex superplastic forming operations. those tools can be applied effectively if you want to develop optimized superplastic forming techniques to explore the plastic deformation conduct of the sheet all through blow forming.  A finite element commercial software ANSYS is used to carry out the simulations and calculation of thickness distribution , forming time and pressure cycle has been formulated  The results obtained by finite element code and the values obtained by theoretical analysis are correlated.