Quantitative analysis of the influence of strain hardening on equal channel angular pressing process

Equal channel angular pressing is a promising severe plastic deformation method. The objective is to achieve high and homogeneous deformation in the workpiece. However, corner gap formed during the process has a pronounced effect on strain homogeneity and should be taken into account for proper die design. Although there exits several publications reporting the effect of strain hardening behavior of the workpiece on corner gap formation, the literature lacks a quantitative study on the subject. In this study, the effects of strain hardening characteristics of the material, strain hardening coefficient (K) and exponent (n) of Hollomon's law, on corner gap formation and strain homogeneity in equal channel angular pressing process were investigated quantitatively by finite element method. The results were compared with the upper bound analysis for the verification of the finite element findings. A series of numerical simulations showed that the process performance can be improved by modifying the die corner curvature accordingly, without running time consuming simulations. (C) 2010 Elsevier B.V. All rights reserved.