PREDICTION OF DEFORMATION AND HOT TEAR FORMATION USING A VISCOPLASTIC MODEL WITH DAMAGE

摘要

A viscoplastic deformation model considering material damage is used to predict hot tear formation in a permanent mold magnesium alloy casting. The simulation model calculates the solid deformation and ductile damage. The viscoplastic constitutive theory accounts for temperature dependent properties and includes creep and isotropic hardening. Ductile damage theory is used to find mechanically induced voiding, and hot tears are expected in regions of extensive damage. Previously performed experiments are used to validate the simulation predictions. The test casting consists of a long horizontal bar connected to a vertical sprue on one side and an anchoring flange on the other. Hot tears are observed at the junction between the horizontal bar and the vertical sprue. The hot tearing severity is manipulated by adjusting the initial mold temperature. The simulation results are in good agreement with the experimental observations, both in terms of location and severity of the hot tears.