A nickel base single crystal （SC） superalloy was directionally solidified using liquid metal cooling （LMC） process at various withdrawal rates. The microstructure was refined as increasing the withdrawal rate from...A nickel base single crystal （SC） superalloy was directionally solidified using liquid metal cooling （LMC） process at various withdrawal rates. The microstructure was refined as increasing the withdrawal rate from 3 to 12 mm/min. However, higher withdrawal rate of 15 mm/min induced the formation of stray grains. Size and volume fraction of the eutectics were found to decrease with the increasing in withdrawal rate. After solution heat treatment at 1250℃, un-dissolved eutectic was observed in specimens. High temperature creep rupture life was observed to be very sensitive to the fraction of these remaining eutectics. Creep rupture tests at 1000℃/235 MPa showed that refined microstructure and low fraction of the remaining eutectic lead to significant improvement of the rupture life.展开更多
利用高温度梯度定向凝固技术——液态金属冷却LMC(liquid metal cooling)技术制备了单晶铸件,采用ProCAST有限元模拟软件包计算了LMC定向凝固工艺下,不同抽拉速度单晶高温合金铸件定向凝固过程的温度场,预测了拉速对单晶生长缺陷的影响...利用高温度梯度定向凝固技术——液态金属冷却LMC(liquid metal cooling)技术制备了单晶铸件,采用ProCAST有限元模拟软件包计算了LMC定向凝固工艺下,不同抽拉速度单晶高温合金铸件定向凝固过程的温度场,预测了拉速对单晶生长缺陷的影响。结果表明,模拟结果与实验结果吻合良好,计算的温度曲线在1100℃以上与实测温度曲线相比误差小于5%;随着抽拉速度的增加,凝固界面下凹,曲率增加,铸件缘板处出现杂晶的倾向增大。展开更多
文摘A nickel base single crystal （SC） superalloy was directionally solidified using liquid metal cooling （LMC） process at various withdrawal rates. The microstructure was refined as increasing the withdrawal rate from 3 to 12 mm/min. However, higher withdrawal rate of 15 mm/min induced the formation of stray grains. Size and volume fraction of the eutectics were found to decrease with the increasing in withdrawal rate. After solution heat treatment at 1250℃, un-dissolved eutectic was observed in specimens. High temperature creep rupture life was observed to be very sensitive to the fraction of these remaining eutectics. Creep rupture tests at 1000℃/235 MPa showed that refined microstructure and low fraction of the remaining eutectic lead to significant improvement of the rupture life.
文摘利用高温度梯度定向凝固技术——液态金属冷却LMC(liquid metal cooling)技术制备了单晶铸件,采用ProCAST有限元模拟软件包计算了LMC定向凝固工艺下,不同抽拉速度单晶高温合金铸件定向凝固过程的温度场,预测了拉速对单晶生长缺陷的影响。结果表明,模拟结果与实验结果吻合良好,计算的温度曲线在1100℃以上与实测温度曲线相比误差小于5%;随着抽拉速度的增加,凝固界面下凹,曲率增加,铸件缘板处出现杂晶的倾向增大。
