A Study on the Hybrid-ECAP Process to Produce Ultra-Fine Materials

Lee, Ju-Hyun; Lee, Jin-Ho

Journal of the Korea Institute of Military Science and Technology 2008;11(4):83-91.

Ju-Hyun Lee, Jin-Ho Lee

초미세 결정립 조직을 만들기 위한 복합전단가공법에 관한 연구

이주현, 이진호

육군3사관학교 기계공학과

Abstract

The development of the equal channel angular pressing(ECAP) process in metals has recently provided a feasible solution to produce ultra-fine or nano-grained bulk materials with tailored material properties. However, ECAP process is difficult to scale up commercially due to requirements of an excessive load. In this paper, a new Hybrid-ECAP process with torsional die is considered to obtain materials of ultra-fine grain structure under low forming load. An upper bound analysis and numerical simulation (DEFORM 3D, a commercial FEM code) are carried out on the torsional die. By the upper bound analysis, analytical expression for the compression force and rotation speed are obtained. By the FEM analysis, the distribution of strain, stress and deformation are obtained. These results show that the Hybrid-ECAP is a useful process because this process can obtain the homogeneous deformations with relatively low forming load. Additionally, due to decreased forming load, die life can be improve.

Key Words: Hybrid-ECAP, Upper Bound Analysis, Finite Element Analysis, Torsion