Ti-25Al-10Nb-3V-1Mo合金的高周疲劳性能及断裂特征

High Cycle Fatigue Properties and Fracture Features of Ti- 2 5Al- 1 0 Nb- 3V- 1 Mo Alloy

实验测定了 Ti- 2 5 Al- 10 Nb- 3V - 1Mo合金 6 5 0℃下高周疲劳 S- N曲线及热暴露后合金的疲劳性能。结果表明 ,Ti- 2 5 Al- 10 Nb- 3V- 1Mo合金具有较高的疲劳强度 ,可以满足转子零件的要求。对比光滑和缺口试样的高周疲劳性能 ,可以看出该合金缺口敏感程度高 ,且随着应力水平的增加而增大。应用 SEM对疲劳变形后的断口进行了观察 ,详细分析了疲劳裂纹的起源与扩展 ,以及裂纹扩展时的微观应力状态。

The high cycle fatigue S- N curves of Ti- 2 5Al- 10 Nb- 3V- 1Mo alloy at650℃ are determined.Some samples are also tested following preexposure at650℃ and70 0℃ respec- tively.The results show that Ti- 2 5Al- 10 Nb - 3V- 1Mo alloy has good fatigue strength which can reach the need of rotor components.The comparison of high cycle properties between smooth and notched specimens indicats that the notched sensitivity of this alloy is high and the sensitivity is getting higher with the stress increasing.In this study,fatigue fracture features are observed in SEM.The fatigue crack initiation and propergation,as well as the micro- stress state are all dis- cussed and analysed in details.