Processing of semi-solid materials using a shear-thickening Bingham fluid model

Abstract

Recently the importance of processing metals and metal matrix composites in semi-solid state is growing rapidly. Performing the shape making operations in the semi-solid state provides a better opportunity to control the microstructure of the final product. In this paper we are presenting a numerical approach to simulate the compression molding of semi-solid materials. A phenomenological constitutive relation based on the Bingham fluid model and the Power-law model is proposed. The model has four adjustable parameters. These parameters are evaluated by comparing with the experimental results. Results are presented for Sn-15%Pb alloy system. The model is then used to describe the unsteady flow of semi-solid materials in compression molding. The Generalized Eulerian-Lagrangian (GEL) formulation is used to locate the free surface while maintaining the solid boundaries. Yielded and unyielded portions of the charge are identified.