Characterization of semi-solid slurry using a novel “Rheo-Characterizer” apparatus

The rheological properties of A357 semi-solid slurries, produced under different conditions using the SEED process, were analyzed with a novel “Rheo-Characterizer” apparatus. The TiB2 grain refiner was also added to evaluate the impact on the microstructure and the cutting force. The α-Al particles and grain size were measured under different processing conditions. The effect of the solid fraction on the resulting cutting force curve was also investigated by altering the cutting temperature. The results show that the “Rheo-Characterizer” is capable of differentiating between the microstructural morphologies and the solid fraction present in the slug. A simple theoretical model was proposed to better understand the relationship between the microstructure and the cutting behaviour of the semi-solid slurry. The model, together with an analysis of the deformation phenomena observed on the wire and the slug, roughly predicts the principal characteristics of the experimental cutting curves.