中文摘要：

基于经典形核理论,考虑温度和保温时间对沉淀相析出的影响,建立了镍基高温合金中γ′沉淀相析出模型.同时结合GH738合金在等温时效实验条件下获得的γ′相析出特征值数据,验证模拟计算结果的相对正确性.结果表明,沉淀相析出过程经典动态模型可较好预测多元复杂镍基合金体系γ′相以均匀形核为主的析出过程.进一步利用该模型对GH80A,GH738,U720Li和DD407共计4种典型高温合金计算分析了Al和Ti含量及其比值变化对γ′相析出行为的影响.结果表明,对于γ′相平衡态含量,Al的作用程度比Ti大;而在Al＋Ti总量不变的前提下,Ti含量增加将对提高γ′相的析出驱动力,从而减少完全析出时间有较大的贡献;Ti含量的增加也将使得沉淀相在析出初期的数量增加,而尺寸减小.

英文摘要：

Based on the classical nucleation theory,and considering the effects of heat temperature and preservation time on precipitation,the 7＇ precipitation model in nickel-based superalloy was established.In combination with the characteristic value data of 7＇ precipitation which was got by isothermal aging experiment of GH738 alloy,the relative accuracy of simulation result was verified. Results show that the classic dynamic model of the precipitation can better forecast that 7＇ phase of multiple complex nickel-based alloy system mainly precipitate by uniform nucleation.Further,precipitation model was combined with four typical superalloys GH80A,GH738,U720Li and DD407.The effects of the contents of Al,Ti and its ratio change on the precipitation of 7＇ were calculated and analyzed.Results showed that the better role of Al than Ti on equilibrium content.Under the premise of equal amount of Al ＋ Ti,the increasing of Ti had a greater contribution to the driving force of precipitation and complete precipitation time,and increased the volume fraction of the beginning of precipitation,but reduced the size of precipitated phase.