合金凝固路径的预测
(State Key Laboratory for Solidification Process,
Northwestern Polytechnic University, Xi＇an 710072, China)
摘 要: 使用DTA和LMC定向凝固淬火技术分别确定了Al-Cu-Zn合金富铝角的液相面和固/液界面溶质分凝因数。 基于一维平板模型的枝晶几何形状描述，使用数值模型计算了Al-1.5Cu-3Zn合金凝固过程中的液相浓度和平衡温度。发现在平衡凝固条件下， 液相在α相区内结束凝固， Scheil非平衡凝固条件下的凝固过程在单变量线上结束，样品中初生晶相的含量为97.4％，非平衡共晶含量为2.6％； 同时分析了液相混合条件对凝固路径的影响。
关键字: Al-Cu-Zn合金； 凝固路径； 相图； 数值模型
Al-1.5Cu-3Zn fromexperimental phase
diagram and numerical model
（State Key Laboratory for Solidification Process,
Northwestern Polytechnic University, Xi＇an 710072, China）
Abstract:The liquidus surface and solute partition coefficience in the Al-rich corner of the Al-Cu-Zn alloy were determined by differential thermal analysis (DTA) and LMC directional solidification and quenching technology.A numerical model for the calculation of solidification path was developed on the basis of the platelike dendrite geometry. The equilibrium solute concentration and liquidus temperature were calculated in the Al-1.5Cu-3Zn alloy.The solidification path ended in the α(Al) phase domain in the case of equilibrium solidification, and the path ended in the liquidus valley for the case of the Scheil non-equilibrium solidification. The volume fraction of the primary phase was 97.4% and that of eutectic was 2.6%.The effect of incomplete mixing of the rejected solute on the solidification path was also discussed.
Key words: Al-Cu-Zn alloy; solidification path; phase diagram; numerical
