Non-equal Channel Multi-Angular Extrusion (NECMAE): A Design for Severe Plastic Deformation—Proof of Concept

Equal channel angular pressing (ECAP) is currently the most widely used severe plastic deformation (SPD) process. The current work presents a validated finite element modelling for a new SPD process named “non-equal channel multi-angular extrusion (NECMAE)”. NECMAE is combined of two stages; the first stage is a standard ECAP, while the second stage experiences a reduction in cross-sectional area. The effects of different reduction in area—in NECMAE—on material plastic deformation, corner gap, stress distribution and required load were examined. In addition, a mathematical model was developed in order to trace the shear strains imposed on the material at different stages. Cases with higher reduction in area were found to have smaller corner gap, higher and uniform plastic deformation, as well as higher loads. The magnitude of maximum stresses was unaffected by different designs; the shape and size of the highly stressed material varied with die design. The current results were explained in terms of; (1) back pressure; (2) strain hardening; (3) shear angle of the second stage; and (4) shear strain history.