Modeling and optimization of superplastic forming of Weldalite(TM) 049 sheet products.

摘要

The present research study introduces a process system approach for the superplastic forming process (SPF). The material of the study is the Al-Cu-Li alloy Weldalite{dollar}rmsp{lcub}TM{rcub}{dollar} 049 (W049); the alloy is a member of the Al-Li alloy family, which has been of great interest to the aerospace industry due to its high strength-to-weight ratios.; The study consisted of two phases: experimental and numerical. The experimental investigation was directed towards the development of an understanding of the superplastic flow behavior of W049. This was achieved through superplastic uniaxial constant true strain rate testing. The data generated from these tests was used to generate process maps for W049 which correlate the processing conditions to the formability and the developed microstructure. Pans and cones were formed, as part of the experimental study, to evaluate the effect of post forming heat treatments on the service properties of the alloy and to be used in verifying the numerical model. The results of the investigation showed that the activation energy was a function of the strain rate. Also, the developed microstructure, together with the analyzed process kinetics, indicate that dynamic recrystallization and grain boundary sliding are the dominant mechanisms for superplastic deformation in W049. In the numerical study, the superplastic forming process is modeled using the finite element code ABAQUS. The results showed good agreement with the experimental findings.