A 3D coupled hydro-mechanical granular model for simulating the constitutive behavior of metallic alloys during solidi cation

Abstract

A 3D coupled hydro-mechanical granular model has been developed and val- idated to directly predict, for the rst time, hot tear formation and stress- strain behavior in metallic alloys during solidi cation. This granular model consists of four separate 3D modules: (i) The Solidi cation Module (SM) is used for generating the solid-liquid geometry at a given solid fraction; (ii) The Fluid Flow Module (FFM) is used to calculate the solidi cation shrink- age and deformation-induced pressure drop within the intergranular liquid; (iii) The Semi-solid Deformation Module (SDM) simulates the rheological behavior of the granular structure; and (iv) The failure module (FM) simu- lates crack initiation and propagation. Since solid deformation, intergranular

ow, and crack initiation are deeply linked together, the FFM, SDM, and FM are coupled processes. This has been achieved through development of a new three-phase interactive technique that couples the interaction between intergranular liquid, solid grains and growing voids. The results show that the pressure-drop, and consequently hot tear formation, depends also on the compressibility of the mushy zone skeleton, in addition to the well-known contributors (lack of liquid feeding and semi-solid deformation).