3D MULTI-PHASE FIELD SIMULATION ON BINARY EUTECTIC ISOTHERMAL SOLIDIFICATION

摘要

As an important structural material, eutectic structure is of great theoretical significance to study the mechanism of eutectic formation and to optimize casting processing. Since 3d simulation can demonstrate the eutectic morphology directly, it is necessary to study 3d eutectic growth systematically with numerical simulation to obtain a detailed law of 3d eutectic growth. In this paper, a 3d multi-phase field model is developed from Nestler et al.'s 2d multi-phase field model to study the binary eutectic growth and morphology evolution with the ideal symmetrical diagram. Performing the calculation by altering initial lamellar spacing to reappear the mechanism of spacing selection veritably, it's found that the mechanism of lamellar spacing selection in 3d is similar to that in 2d but the former is more complex. Moreover, by altering the volume fraction of the eutectic minor phase, the simulation of rod-like to lamellar eutectic transition is also performed. Simulated results indicate that the less the minor phase volume fraction, the more rod-like structures prefer over lamellar structures when the minor phase volume fraction is not more than approximately 0.3.