Analysis of deformation behavior in 3D during equal channel angular extrusion

Abstract

Strain distribution on the cross-sectional area of the workpiece ( X plane) normal to the pressing direction was examined based on the strain contours obtained in full 3D along various diameter directions. The largest inhomogeneous strain distribution developed along vertical direction of the cross-sectional area, while the strain distribution along the transverse direction was relatively uniform. Variation in magnitude and sign of shear and normal stress components during passage of the workpiece through the die was computed. Among the three shear components acting on the shear planes within the die corner region where ECAE deformation is confined to occur, the shear stress along the diagonal direction connecting the sharp and round corners is overwhelmingly dominant over the other shear components. Near pure shear condition is only observed on the plane that is in the middle of the die corner region where two channels are interconnected, being inclined by 45° to the pressing direction. As shear and normal components additionally considered in 3D is much smaller than the other components considered in 2D, stress state in 3D is can be approximated to be that in 2D.