相场法模拟NiCu合金非等温凝固枝晶生长

利用相场模型与溶质场、温度场进行耦合计算,以Ni-40.83%Cu合金为例模拟了二元合金枝晶生长过程.系统研究相场模型中相场和温度场耦合强度对枝晶形貌和浓度分布的影响.模拟结果表明:随着耦合强度的增加,相场受温度场的影响加大,界面前沿变得不稳,扰动被放大,主枝上出现了二次枝晶.同时,枝晶尖端的生长速率增大,而枝晶尖端的曲率半径减小,枝晶前沿的溶质富集现象也更严重;另外,计算结果与Ivantsov理论符合较好. 关键词： 相场法 NiCu合金 枝晶生长 Ivantsov理论

Phase-field simulation of Non-Isothermal dendritic growth of NiCu alloy

Phase-field model is used and The dendrite growth of a Ni-40.83%Cu binaryalloy under were simulated by the model coupled with solute field and temperature field.The effects of solidification latent heat on the growth of equiaxed dendrite, distribution of solute field and temperature field in undercooled liquid alloy were analyzed.The results indicate that the dendritic has well-developed secondary arms as undercooling degree increases.Correspondently, the solute Peclet number and the tip speed increases, the tip radius decreases, and the solute segregation in solid-liquid interface increases. The results agree well with Ivantsov theory.