(1. 南京航空航天大學 材料科學與技術(shù)學院，南京 210016；
2. 哈爾濱工業(yè)大學 現(xiàn)代焊接生產(chǎn)技術(shù)國家重點實驗室，哈爾濱 150001)
摘 要: 通過構(gòu)建元胞自動機與有限差分耦合的CA-FD(cellular automaton-finite difference)模型，實現(xiàn)Ni-Cr二元合金焊接熔池柱狀枝晶生長過程的模擬，研究熔池邊緣柱狀晶的生長過程以及該過程中的溶質(zhì)濃度分布形態(tài)。模擬結(jié)果再現(xiàn)了焊接熔池中二次、三次枝晶的生長，枝晶間的競爭生長以及晶界偏析等微觀現(xiàn)象。基于模擬結(jié)果深入分析了焊接熔池中枝晶生長的特點，同時對溶質(zhì)濃度場進行了定量分析。對模擬結(jié)果的分析表明，焊接熔池中枝晶間競爭生長激烈，枝晶形態(tài)復雜，枝晶偏析和晶界偏析顯著。
關(guān)鍵字: Ni-Cr二元合金；柱狀枝晶；焊接熔池；元胞自動機；數(shù)值模擬
weld pool of Ni-Cr binary alloy
（1. College of Material Science and Technology, Nanjing University of Aeronautics and Astronautics,
Nanjing 210016, China;
2. State Key Laboratory of Advanced Welding Production Technology,
Harbin Institute of Technology, Harbin 150001, China）
Abstract:A cellular automaton-finite difference (CA-FD) model was established and the dendritic grain growh processes in the weld pool of Ni-Cr binary alloy were simulated based on this model. The dendritic grain growth processes in the edge of the weld pool and the solute distribution during the growth processes were studied. The simulated results reproduce the growth of secondary and tertiary dendrite arms, the competative growth and the grain boundary segregation, etc. The characters of the dendrite growth process in the weld pool were analyzed and the solute fields were quantitatively analyzed. It is indicated that the competative growth of columnar dendrite grain in weld pool is acute, the dendrite morphologies are complicated and the macro and micro segregations are obvious.
Key words: Ni-Cr binary alloy; columnar dendrite grain; weld pool; cellular automaton; numerical simulation
