Numerical simulation of macrosegregation of indium phase in rapidly solidified Al-In hypermonotectic sheets

Numerical simulation and experimental methods have been adopted to study the macrosegregation of indium phase in rapidly solidified Al-In hypermonotectic sheets. Based on the particle separation method, a numerical model reflecting the actual solidification process has been developed to simulate the precipitating, coarsening, and moving process of secondary phase droplets under conditions of variable temperature, thermophysical properties, and supersaturation. In this model, the droplets are divided into various size classes according to their radius and a stochastic collection equation is used to deal with collisions, so the length of computation is reduced sharply, which makes application of the particle separation method possible. Simulation and experimental results show that indium particle distribution is uniform when the specimen thickness is less than ∼4 mm. With increasing specimen thickness above 4 mm, indium particle distribution becomes more and more inhomogeneous. Good agreement between calculated and experimental results verifies that the model established in the present work has adequate predictive ability.