Numerical Simulation And Experimental Investigation Of Deformation Mechanism In Equal Channel Angular Pressing/Extrusion Process

The inherent microstructure of materials has a great influence on their macrostructure characteristics. According to Hall-Petch relationship, it is known that the strength and the hardness of the materials usually increase with the decrease of the average dimension of crystalline grains. Therefore, seeking the material refinement processing technology has an important industrial prospect. The equal channel angular pressing (ECAP) was originally developed by Segal to achieve bulk Ultra fine-grained (UFG) metals in later 1970s. The processes are known to create grains well under 1μm in diameter using aluminum alloys. The processes have the capability to produce bulk Ultra-Fine Grains (UFG) materials without loose holes. The processes effectively avoids the harmful effects for remained holes in the materials, and the bulk UFG materials have many novel properties different from the common materials [4-8]. Those materials can be used as super high strength materials, intelligent metal materials and super plastic materials.The grain refinement of the ECAP process is dependent on the accumulated effective strain in the workpiece. It has important theoretical values and industrial prospects to obtain the refining mechanism and production process of the bulk UFG materials. ECAP process is investigated by using numerical simulations and experimental studies in this paper. Using commercial metal forming finite element code CASFORM/PC and DEFORM-3D, ECAP process is analyzed numerically in this paper. The die geometry and process parameters of the ECAP have large influence on the extrusion process. The deformation mechanism and proper process parameters of ECAP are obtained through analysis of die geometry and process parameters. The single-pass ECAP process is a non-uniform severe plastic deformation process. The authors in this paper give a node mapping method, in which the finite element simulation of the multi-pass equal channel angular pressing processes can be realized. The deformation distribution rules of the multi-pass ECAP processes for different processing routes are...