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 paper,for the first time,derives the analytical formulae and constraint equations for strain,strain-rate and stress of superplastic extrusions through cone-shaped die by simulating displacement function.In the present work,typical superplastic alloy Zn-5wt%Al was chosen as the example,so the results are of universal significance.The method can even be generalized to non-typical superplastic materials.