(中北大學(xué) 材料科學(xué)與工程學(xué)院，太原 030051)
摘 要: 采用耦合熱擾動(dòng)的相場模型，對(duì)Ni-Cu合金枝晶生長中的枝晶形貌和微觀偏析進(jìn)行計(jì)算和分析，并研究過冷度對(duì)其凝固過程中溶質(zhì)分布的影響。結(jié)果表明：隨著過冷度的增加，二次枝晶變的更發(fā)達(dá)，枝晶主干變細(xì)，一次枝晶干軸對(duì)稱中心處的溶質(zhì)濃度升高，一次枝晶干和二次枝晶臂間富集的溶質(zhì)更多。過冷度越大，固液界面前沿溶質(zhì)擴(kuò)散層越薄，枝晶的微觀偏析越嚴(yán)重，即溶質(zhì)微觀偏析程度隨過冷度的增大而增大。
關(guān)鍵字: Ni-Cu合金；相場法；過冷度；枝晶偏析
（College of Materials Science and Engineering, North University of China, Taiyuan 030051, China）
Abstract:Based on KKS model coupling the phase field and concentration field, the dendritic growth process model for Ni-Cu alloy during isothermal solidifications was developed. The solute distribution of nickel-copper alloy during the metal solidification was simulated, the effects of supercooling (ΔT) on the highest solute concentration in front of the dendrite tip and solute segregation ratio were studied emphatically. The results indicate that, the larger the supercooling ΔT is, the higher the concentration maximum value in front of the dendrite tip is, the severer the microsegregation is. The supercooling can trigger the growth of the secondary arms and increase the growth rate of the primary dendrite. As the supercooling increases, the microsegregation increases.
Key words: Ni-Cu alloy; phase-field method; super-cooling degree; microsegregation
