PHASE-FIELD SIMULATION OF LAMELLAR GROWTHS FOR A BINARY EUTECTIC ALLOY

摘要

Using the general multi-phase-field model, the binary eutectic solidification is studied to investigate the detailed microstructures in response to different initial lamellar sets. A binary eutectic alloy with an asymmetric phase diagram is chosen. The simulations show the regular or unstable oscillating lamellar structures dependent on the initial lamellar widths of two solid phases. A lamellar morphology map determined by these initial widths is derived, which gives the condition of forming regular lamella. The investigation of interface velocity indicates fast solidification when forming regular lamella, and the disorder growth manner or a large lamellar spacing will cause a low interface velocity. The simulation results are well agreed with the ones from the Jackson-Hunt model.