Discussions on constitutive equations of superplastic 5083 aluminum alloy

A constitutive equation for a fine-grain superplastic material, 5083 Al all oy, is proposed on the basis of combined loading experiments and the classi cal (mathematical, phenomenological) theory of plasticity using the potenti al function. The experiments are performed by applying the combined loads o f axial force and torque to the thin-walled tubular specimen of 5083 Al all oy. A new potential function is proposed by incorporating the second invari ant and third invariant of stress deviator. The proposed constitutive equat ion can predict the mechanical behavior of 5083 Al alloy under the combined loading conditions. (C) 2001 Elsevier Science Ltd. All rights reserved.