铸造高温合金涡轮叶片热冲击疲劳行为研究

Study on Thermal Shock Fatigue Behavior of Cast Superalloy Turbine Blade

为了研究不同材料涡轮叶片热冲击疲劳性能,采用感应加热热冲击试验装置对三种铸造高温合金涡轮叶片进行了试验研究。利用光学相机、视频显微镜和扫描电子显微镜对叶片表面裂纹形貌、叶片横截面和断口形貌进行观察。结果表明:单晶涡轮叶片热冲击疲劳寿命长于定向晶涡轮叶片热冲击疲劳寿命。定向晶涡轮叶片中添加Re元素延长了热冲击疲劳寿命。热冲击疲劳导致裂纹萌生于叶片中截面考核区并沿叶高方向扩展。裂纹的扩展方式与叶片合金成分及铸造工艺有关。

In order to investigate the thermal shock fatigue property of turbine blades with different materials,thermal shock fatigue behavior of the turbine blades cast by three kinds of superalloys was investigated by the thermal shock fatigue equipment with induction heating.Crack morphologies of blade surface,cross section morphologies and fractographs were observed by optical camera,video microscopy and scanning electron microscope.The results showed that the life of the thermal shock fatigue of single crystal superalloy turbine blade was longer than that of directionally solidified superalloys.The life of the thermal shock fatigue was increased with adding Re content in the directionally solidified superalloy turbine blade.The crack initiated at the appraisal area of the turbine blade′s medium section under thermal shock fatigue and propagates along blade height.The crack propagation mode was associated with alloy compositions and cast process of the blade.