A Study on Solutions for Avoiding Liquid Segregation Phenomena in Thixoforming Process: Part I. Constitutive Modeling and Finite Element Method Simulations for Die Design

摘要

The most important factor in the thixoforming analysis with die design is the relationship formulation between the stress and the strain considering the grain size and the deformation of the solid particles with a globular microstructure. In this present work, thus, a new stress-strain relationship formulation described as a function of the separation coefficient is proposed to consider the deformation of solid particles. Constitutive models are implemented by applying Darcy's law for the liquid region and a porous media theory in the case of the solid region. A die designed to fabricate a net shape scroll component using semisolid aluminum alloys was performed using the finite element method (FEM). In the case of the solid fraction f_s = 55 pct, the distributions of strain rate are calculated to assess the deformation behavior of semisolid materials (SSMs) by using the compression test data base of SSMs. By using these results, the effect of the overflow position in die design parameters on the liquid segregation in thixoforming process has been theoretically investigated.