Materials Transactions, Vol.50 No.01 (2009) pp.19-26
© 2009 The Japan Institute of Metals

SPH Analysis of ECAP Process by Using Grain Refinement Model

Ken-ichi Saitoh and Yuuki Ohnishi

Plastic working of metals using severe plastic deformation (SPD) recently attracts interest of researchers, because it is a method that will improve the toughness as well as the strength just by applying enormously large strain on the material. In this study, deformation, stress and strain of aluminum in ECAP (equal channel angular pressing) are analyzed computationally by using smoothed particle hydrodynamics (SPH) method which is one of particle methods. In addition to elastic-plastic constitutive relation, a newly developed theoretical framework in which grain refinement process is involved is proposed here. We try to implement the framework into the SPH computation. The main idea to conduct grain refinement in the material is that applied energy by plastic working causes continuous change in the total area of grain boundaries and averaged diameter in the material becomes smaller and smaller. The reasonable change can be observed by using such simple but theoretical framework. The present paper is focused on implication, formulation and possibility of the grain refinement model.

(Received 2008/7/22; Accepted 2008/9/9; Published 2008/10/22)

Keywords: severe plastic deformation, numerical analysis, smoothed particle hydrodynamics, grain refinement, equal-channel angular pressing (ECAP), plastic work, aluminum

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