A Stochastic mesoscopic model for predicting the globular grain structure and solute redistribution in cast alloys at low superheat

It is well known that casting at low superheat has a strong influence on the solidification morphology and macro- and microstructures of the cast alloy. This paper describes a stochastic mesoscopic solidification model for predicting the grain structure and segregation in cast alloy at low superheat. This model was applied to predict the globular solidification morphology and size as well as solute redistribution of Al in cast Mg AZ31B alloy at superheat of 5°C produced by the Magnetic Suspension Melting (MSM) process, which is an integrated containerless induction melting and casting process. The castings produced at this low superheat have fine globular grain structure, with an average grain size of 80 μm, which is about 3 times smaller than that obtained by conventional casting techniques. The stochastic model was found to reasonably predict the observed grain structure and Al microsegregation. This makes the model a useful tool for controlling the structure of cast magnesium alloys.