(113a) 2D Multi-Particle Finite Element Modelling on the Cold Isostatic Pressing of Al Powder

Anliang Lu, Xizhong An*

School of Metallurgy, Northeastern University, Shenyang 110004, PR China

Abstract

In this article, the cold isostatic pressing (CIP) of Al powders with different initial packing structures was numerically simulated in 2D using multi-particle finite element method (MPFEM) from particulate scale. The effects of external pressure and initial packing structures on the packing densification and performance of the compacts were systematically studied. Various macro/micro properties (such as relative density and distribution, local stress and distribution, and particle deformation behavior etc.) and the densification dynamics/mechanisms were characterized and analyzed. Corresponding comparison with the die compaction was also conducted. The results show that the relative displacement of particles is much less and the particle shape is more regular for CIP of ordered initial packing structure than those for CIP of random initial packing structure, and the distributions of relative density and local stress are more homogeneous in the compact for the former case. Compared with the die compaction, the formability of CIP is much better; also the compact has higher relative density and more uniform density and stress distributions. The normal stresses are transmitted in all directions in the CIP compact because the external force is applied uniformly to the outer surface of the rubber mold from all directions in the whole process, while the stresses are directional along the certain loading path during die compaction.

Keywords: Aluminum powder; Cold isostatic pressing; Multi-particle FEM; Densification mechanism; Particulate scale modeling