抽拉速度对单晶叶片定向凝固过程的影响

Effect of Withdrawal Rate on Solidification Process of Single Crystal Turbine Blade

建立了单晶高温合金涡轮叶片定向凝固过程数值计算的有限元模型,利用Pro CAST软件模拟计算了叶片在定向凝固工艺下不同抽拉速率时叶片凝固过程的固-液界面形状、纵向温度梯度、冷却速率和二次枝晶间距,预测了抽拉速率对杂晶形成的影响。结果表明,随着抽拉速率增大,温度梯度略有降低,二次枝晶间距减小;随着抽拉速率增大,叶片冷却速率增大,而起晶器和选晶器中的冷却速率不受抽拉速率的影响。

The FEM model of solidification process of single crystal superalloy turbine blade had been established, and the shapes of solidus-liquidus interface, temperature gradient, cooling rate and dendritic secondary arm spacing at various withdrawal rates during directional solidification process had been calculated with ProCAST. The impact of withdrawal rate on the formation of stray grains was predicted. The results show that the temperature gradient and the dendritic secondary arm spacing decrease with the increase of withdrawal rate, and the cooling rate of the blade is found to increase with the increase of withdrawal rate, but the cooling rate in the starter block and grain selector are almost the same at various withdrawal rates.