【摘要】 使用OM、SEM和EDS等手段，研究了第三代镍基单晶高温合金DD33不同V型缺口取向([100]、[210]和[110])片状试样从室温到不同上限温度(1000℃、1100℃和1200℃)的热疲劳过程中裂纹的萌生和扩展行为。结果表明，在三种上限温度，DD33合金的热疲劳性能均出现明显的各向异性。在三个上限温度[100]取向试样均表现出最好的热疲劳性能；上限温度为1000℃和1200℃[110]取向试样的热疲劳性能最差，上限温度为1100℃[210]取向试样的热疲劳性能最差。不同取向试样的热疲劳裂纹的萌生和扩展行为，均呈现出一定的晶体学取向规律。热应力、氧化以及滑移系的开动，导致不同取向试样裂纹的扩展速率不同。更多还原

【Abstract】 The crack initiation and propagation behavior of a third-generation single crystal superalloy DD33 with V-notches of different orientations([100], [210] and [110]) during thermal fatigue tests: samples were hold at different high-temperatures(1000oC, 1100oC and 1200oC respectively) for 60 s and then quick quenching into water as one cycle, was investigated by OM, SEM and EDS. The results show that the thermal fatigue properties of DD33 show obvious anisotropy tested at different high-temperatures.The initiation and propagation behavior of thermal fatigue cracks in samples with different notch orientations show the dependence of crystallographic orientation. At 1000oC/1100oC/1200oC, the [100] orientated specimens exhibit the best thermal fatigue performance. The thermal fatigue performance of the [210] oriented sample is the worst at 1100oC, while the thermal fatigue performance of the [110] oriented sample is the worst at 1000oC and 1200oC. The thermal stress, oxidation, and the operation of slip systems result in the difference in crack growth rate of samples with different notch orientations.更多还原