Comparative Analysis of Actual Processing Conditions in ECAE between FEM and Both Analytical and Experimental Results

Abstract

Equal Channel Angular Extrusion (ECAE) process is a severe plastic deformation (SPD) process whose principal purpose is to impart high values of deformation to the processed material, which leads to a grain size reduction and hence to an improvement in its mechanical properties.

Although the strain achieved is important in the process, the required force and the extrusion pressure are equally important design factors. Like other metal-forming processes, a compromise solution between the strain achieved and the force required has to be applied.

In this study, both the finite element method (FEM) and analytical methods based on the upper bound method (UBM) were used for modelling and comparing the forces required in the ECAE process when strain-hardening materials are considered. In addition, experimental results were carried out in order to validate the FEM modelling.

Several FEM simulations, with different geometric parameters, were run, and by using design of experiments (DOE) tools, a mathematical model was obtained. By using this model, the processing extrusion pressure can be predicted. In order to compare the actual behaviour of processed materials with FEM and analytical results, a 5083-AA was chosen as processed material. Nevertheless, the methodology developed could be applied to different materials with strain hardening.

Keywords:

• Equal channel angular extrusion (ECAE)
• Finite element method (FEM)
• Severe plastic deformation (SPD)
• Upper bound method (UBM)

ACKNOWLEDGMENT

The authors acknowledge the support given by the Ministerio de Ciencia e Inovación (Spain) (Research Project MAT2006-14341-C02-02).