(中国科学院 金属研究所，沈阳 110016)
摘 要: 研究了高应力水平下加载波形对Ti-60高温钛合金疲劳损伤行为的影响。结果发现：对于在峰值应力处保载2 min的加载波形，试样的疲劳寿命明显低于无保载的加载波形的试样的寿命；在保载疲劳条件下，单位循环周次内材料的疲劳变形明显增大。SEM观察表明，在保载波形下，疲劳源出现在样品内部，而无保载的加载波形下疲劳裂纹源于样品次表面。TEM观察表明，在两种疲劳加载条件下，都有( 011)滑移系启动。
关键字: 高温钛合金；Ti-60合金；加载波形；保载；疲劳损伤
（Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China）
Abstract:The effect of loading waveform on fatigue damage behavior of Ti-60 alloys at high stress level was studied. The results show that, under the loading waveform with 2 min dwell at the peak stress, the fatigue life is shorter than that without dwell. The fatigue strain in a unit cycle under the dwell fatigue condition is obviously larger than that under the no-dwell fatigue condition. It is observed by SEM that, under the dwell fatigue condition, the fatigue crack originates from the interior of specimens, while under the no-dwell fatigue condition, the fatigue crack originates from the subsurface of specimens. TEM observation indicates that, under the two loading waveforms, ( 011) slip system is activated.
Key words: high-temperature titanium alloy; Ti-60 alloy; loading waveforms; dwell; fatigue damage
