ANALYTICAL THEORY OF SUPERPLASTIC EXTRUSION

The forward extrusion through cone-shaped die, which is the basis for establishing the extrusion theory, can be simply considered to be two- dimensional in a spherical coordinates system in its treatment. This p aper, for the first time, derives the analytical formulae and constrai nt equations for strain, strain-rate and stress of superplastic extrus ions through cone-shaped die by simulating displacement function. In t he present work, typical superplastic alloy Zn-5wt%Al was chosen as th e example, so the results are of universal significance. The method ca n even be generalized to non-typical superplastic materials.