Characterization of Superplastic Behavior of AA2195 by Bulging Test

摘要

Superplasticity is the ability of polycrystalline materials to deform plastically to exhibit very large strains. Using this property in manufacturing process makes many of aerospace components lighter and stiffer, with efficient energy and cost saving. Since in most sheet metal forming operation biaxial as well as uniaxial stress state exists, it is important to understand superplastic behavior as a function of stress state. The main requirement of superplastic deformation includes high strain rate sensitivity, lack of necking, limited range of strain rate, and elevated temperatures. In this study, materials properties of 2195 aluminum-lithium alloy during superplastic deformation were obtained from biaxial bulging test. Aluminum-lithium alloy is a light weight metal that has been used as substitute for conventional aerospace aluminum alloys. At constant gas pressure, the strain rate in which the metal sheet experiences varies and therefore the strain rate sensitivity can be obtained in a single loading. Tensile tests were performed at elevated temperature and materials parameters were compared with the one obtained from biaxial bulging tests.