(1. 哈爾濱工業(yè)大學(xué) 現(xiàn)代焊接生產(chǎn)技術(shù)國家重點(diǎn)實(shí)驗(yàn)室，哈爾濱 150001；2. 南京航空航天大學(xué) 材料科學(xué)與技術(shù)學(xué)院，南京 210016)
摘 要: 基于元胞自動機(jī)方法構(gòu)建了枝晶生長數(shù)值模型，并將其應(yīng)用于Al-Cu二元合金凝固過程的模擬。在該模型中，枝晶尖端生長速度模型基于溶質(zhì)守恒建立。模擬過程中重點(diǎn)考慮不同冷卻速率及形核條件對柱狀樹枝晶形態(tài)與溶質(zhì)偏析的影響。計(jì)算結(jié)果表明，凝固過程中溶質(zhì)易于富集在枝晶臂之間的封閉或半封閉區(qū)域。同時，隨著冷卻速率加大，晶界偏析變得更為顯著。形核密度在一定程度上影響著枝晶形態(tài)，特別是影響著二次和三次枝晶的生長。
關(guān)鍵字: 枝晶生長；數(shù)值模擬；元胞自動機(jī)
（1. State Key Laboratory of Advanced Welding Production Technology, Harbin Institute of Technology, Harbin 150001, China;2. School of Materials Science and Technology, Nanjing University of Aeronautics & Astronautics, Nanjing 210016, China）
Abstract:A dendrite grain growth model that is based on cellular automaton method was developed and applied to simulate the columnar dendrite grain growth during the directional solidification process of Al-Cu binary alloys. And the velocity model was based upon the solute conservation at the solid/liquid interface. The influences of different cooling speeds and different nucleation conditions on the dendrite morphologies and solute segregation were considered. The results indicate that the solute of high concentration liquids is easy to concentrate in the closed or semi-enclosed zones among secondary or tertiary dendrite arms. The grain boundary segregation becomes more severe when the cooling speed is increased. At the same time, the nucleation density affects the dendrite morphologies, especially the growth of secondary and tertiary dendrite arms.
Key words: dendrite growth; numerical simulation; cellular automaton
