An upper-bound approach for equal channel angular extrusion with circular cross-section

In the present work, for the first time, an upper-bound approach is used to analyze the equal channel angular extrusion with circular cross-sections. Based on this model the power dissipated on all frictional and velocity discontinuity surfaces are determined and the total power optimized analytically. To compare the theoretical results with experiments, an ECAE die with a circular cross-section, having sharp corner was used to determine experimental extrusion force. The developed model predicts that the size of the plastic deformation zone and the relative extrusion pressure increase with increasing the constant friction factor. In addition the results show that there is a good agreement between the theoretical and experimental load displacement curve.