AN ORTHOTROPIC FLOW RULE FOR SUPERPLASTIC TI-6AL-4V

During uniaxial testing of rolled Ti-6Al-4V in the superplastic regime , the initially round cross sections of the test specimens became oval . The relationship between this macroscopic anisotropy and the microst ructure was modeled by assuming that the lateral flow during uniaxial tests depends on the alpha phase grain shape in the lateral plane but is independent of the directional grain size parallel to the axis of d eformation. With this assumption, the behavior can be generalized to d etermine the full, multiaxial compliance in terms of the alpha grain s hape. Therefore, with no additional requirements for material testing and only one additional material parameter, uniaxial superplastic cons titutive relations can be extended to estimate anisotropic flow.