Finite element simulation of severe plastic deformation processes

摘要

Severe plastic deformation (SPD) is a method of converting coarse grained metals into ultrafine grained metals, which possess improved mechanical and physical properties. However, none of the many proposed SPD processes have, as yet, gained a commercial acceptance. The finite element method (FEM) is an invaluable tool, which can help to understand the mechanics of material flow in order to optimize existing SPD processes and develop new SPD processes. The paper reviews the literature on FEM simulation of the most popular SPD process of equal channel angular pressing (ECAP) and presents a number of case studies based on FEM analyses of some other SPD processes. The paper evaluates the use of high pressure torsion with bulk billets, explains differences between forward extrusion and cyclic extrusion compression, and shows how FEM can assists the design of non-classical ECAP processes. In addition to FEM results for batch processes, some FEM results for a new incremental ECAP (I-ECAP) process are presented. Since I-ECAP is capable of processing very long, possibly infinite, billets, it belongs to the group of continuous SPD processes.