Viscosity properties prediction of semi-solid aluminum alloys using finite element analysis based on quenched solidified structure, and experimental validation

For predicting hot tearing during casting process, viscosity properties and constitutive equations in the semi-solid region are required. In this research, viscosity properties of two alloys, which are Al-5mass%Mg alloy with Ti-B grain-refiner and Al-2mass%Cu alloy with Ti-B grain-refiner, are estimated using the image-based modelling method as suggested by Matsushita et al. As to the mechanical properties of the solid phase in semi-solid region, it is found that by using the temperature dependent value rather than the value just below the solidus temperature, the prediction accuracy of the viscosity value in semi-solid region has increased. By comparing the obtained numerical properties with the experimental properties, it is found that the method can predict the viscosity properties of Al-5mass%Mg alloy and Al-2mass%Cu alloy in the semi-solid region at the solid fraction where hot tears are likely to occur.