【摘要】 TC25G合金在长期时效过程中析出Ti₃Al（α₂相）和硅化物。为了评估析出物的作用，设计了3种热处理工艺，并详细对比分析了热处理对合金蠕变行为的影响。结果表明，HT2合金的抗蠕变性能优于HT3合金，说明α₂相具有显著的析出强化效果。此外，当温度低于或等于570℃和应力低于或等于200 MPa时，HT1合金的抗蠕变性能与HT3合金接近，表明蠕变前析出的硅化物减弱α_s相粗化所引起的蠕变变形程度。而在600℃和250 MPa时，HT1合金的抗蠕变性能优于HT3合金，表明HT1合金中动态析出的硅化物充足时，同样也能抵抗合金的蠕变变形。HT1、HT2和HT3合金的应力指数范围为1.7～1.9（550℃）和3.7～4.4（600℃），表明硅化物与α₂相的析出量不影响合金的蠕变机制。蠕变激活能的增加是由大量硅化物与α₂相的析出对相界迁移和位错运动的抑制作用加强所导致。更多还原

【Abstract】 In TC25G alloy,Ti₃Al （α₂ phase） and silicide were precipitated during long-term aging.To access the effect of precipitates,three heat treatment processes were designed.The effects of these heat treatments on the creep behavior of alloy were compared and analyzed.The results show that the creep resistance of HT2 exceeds that of HT3,highlighting a significant precipitation strengthening effect of α₂ phase.Furthermore,at temperatures and stresses lower than or equal to 570°C and 200 MPa,respectively,the creep resistance of HT1 is close to that of HT3,suggesting that silicide precipitated before creep attenuates the strengthening of creep deformation caused by the coarsening of α_s phase.At600°C and 250 MPa,the creep resistance of HT1 is significantly higher than that of HT3,indicating that when the dynamic precipitation of silicide in HT1 is adequate,it also resists the creep deformation of the alloy.The stress exponent for HT1,HT2 and HT3 ranges 1.7-1.9 （550°C） and 3.7-4.4 （600°C）,indicating that the amount of silicide and α₂ phase doesn’t affect the creep mechanism.The increase in creep activation energy is attributed to the enhanced inhibition caused by lots of precipitates on phase boundary migration and dislocations motion.更多还原