Three-dimensional MPFEM modelling on isostatic pressing and solid phase sintering of tungsten powders

摘要

Particulate scale three-dimensional CIP and solid phase sintering of tungsten powder in powder metallurgy process was numerically reproduced using MPFEM method. The effects of initial packing structures on the densification behavior of the tungsten powders during CIP and sintering were systematically investigated. Various macroscopic and microscopic properties including relative density, overall/local stress distributions, deformation status, pore filling behavior as well as densification mechanisms were characterized and analyzed. The results indicate that the initial packing structure before CIP plays an important role in determining the properties of both green compact and sintered part after compaction and sintering. Detailed analyses of individual particles revealed that the particles with larger deformation tend to generate greater stress concentration during CIP and sintering; meanwhile, the stress distribution in different location of each particle also demonstrated that a close relationship exists between the stress concentration/release process of individual particles and their initial packing structure before CIP. (C) 2019 Elsevier B.V. All rights reserved.