Globularization of Primary Phase of Al–7Si–0.3Mg Alloy During Cooling Slope Processing and Isothermal Holding

Abstract

This study is aimed towards process design for semi-solid slurry generation of Al–7Si–0.3Mg alloy using cooling slope as a slurry maker, and subsequent isothermal holding to promote globularization of slurry microstructure. The study primarily reports globularization mechanism of cooling slope processed semi-solid slurry of the alloy, and efforts are directed to establish process control by investigating the effect of coarsening during isothermal holding on the shape, size and distribution of primary Al grains. As an outcome of this study, we propose a modified Lifshitz–Slyozov Wagner equation to quantify the effect of coarsening mechanisms prevailing during isothermal holding of the said alloy slurry. The evolution of primary phase morphology due to addition of grain refiner has also been studied and ideal processing condition is identified for the end goal of component development through rheo pressure die casting route.