(西北工業(yè)大學(xué) 凝固技術(shù)國家重點實驗室，西安 710072)
摘 要: 借助于多相場模型， 利用移動盒算法模擬了小Peclet數(shù)下二元共晶模型合金的定向凝固過程。 同時研究了共晶生長層片間距調(diào)整機制。 模擬結(jié)果表明： 當(dāng)初始層片間距小于最小過冷層片間距時， 層片調(diào)整通過兩相的競爭生長與層片湮沒進行； 相反， 當(dāng)初始層片間距大于最小過冷理論時， 層尖的形核分叉生長使層片生長趨于穩(wěn)定； 再現(xiàn)了共晶1λ振蕩不穩(wěn)定性生長， 通過分析局部動力學(xué)得出1λ振蕩不穩(wěn)定性生長原因為溶質(zhì)再分配與共晶兩相的體積調(diào)整。
關(guān)鍵字: 多相場法； 定向凝固； 二元共晶
ZHAO Da-wen, FAN Jian-feng
（ State Key Laboratory of Solidification Processing, Northwestern Polytechnical University,
Xi'an 710072, China）
Abstract: The unidirectional solidification process of a binary eutectic model alloy at low Peclet number was simulated by multi-phase field method together with moving box algorithm. The selection mechanism of lamellar spacing was also studied. The simulation results show that, when the initial lamellar spacing is smaller than that under the minimal undercooling theory, to restabilize the lamellae growth, the annihilation of lamellae occurs; on the contrary, new phase at the top of lamellae nucleates. Moreover, the eutectic period-preserving oscillatory instability (1λ oscillatory) is recurred, which results from the solute redistribution and the volume adjustment of two eutectic phases.
Key words: multi-phase field method; unidirectional solidification; binary eutectic
