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采用相场法模拟了Ni-Cu二元合金非等温凝固过程溶质梯度对枝晶生长的影响。结果表明:非等温凝固时,潜热的释放使固相区的温度比液相中的高,在二次枝晶生长较为密集的中心区域温度最高,固相区温度升高会使得金属重熔,发生重熔现象,晶体的生长速度和凝固区域的温度随之出现波动。溶质梯度对溶质分布影响较大,溶质梯度增加,固相率提高,溶质分配系数k增大,固相区溶质富集,形成了过饱和的固相,溶质截流效应明显。
Phase-field method was used to simulate the effect of solute gradient on dendrite growth during non-isothermal solidification of Ni-Cu binary alloy. The results show that when the non-isothermal solidification occurs, the release of latent heat makes the temperature of the solid-phase region higher than that of the liquid phase, and the temperature is highest in the central region where the secondary dendrite grows more densely. Remelting occurs, the crystal growth rate and the temperature of the solidification zone thereupon fluctuations. The solute gradient has a great influence on the solute distribution, the solute gradient increases, the solid fraction increases, the solute partition coefficient k increases, and the solute in the solid phase accumulates to form a supersaturated solid phase.