Three-dimensional finite element analysis of multi-pass equal-channel angular extrusion of aluminum AA1050 with split dies

Abstract

Equal-channel angular pressing (ECAP) is an effective method to produce bulk nanostructured materials with high strength and toughness. Many experimental researches using a conventional solid die have been done so far, but few attempts on finite element analysis have been undertaken to exploit load predictions of the multi-pass ECAP because of difficulty involved with handling the boundary and processing conditions. In this study, split dies were newly designed to reduce the flash formation and the accuracy of finite element simulations of the multi-pass ECAP was improved by introducing better friction condition and saturated flow stress model considering the effect of routes and number of passes. Experiments with commercially available pure aluminum alloy (AA1050) of a square cross-section were carried out using the split dies newly designed for routes A, BC and C up to three passes. The forming simulation tool, CAMPform3D, was currently used to investigate the effect of routes and number of passes in terms of prediction of the forming load and deformation behavior. It was found out that predicted loads obtained from current numerical simulations were reasonably accurate compared to the measured load data for the three-pass ECAP.