本项目拟以先进航空发动机高压涡轮叶片用镍基单晶合金DD6为研究对象，拟从温度、频率、缺陷、氧化等因素对材料超高周疲劳行为影响规律的试验研究入手，对高温条件下材料超高周疲劳裂纹萌生和早期扩展机制以及频率效应进行深入的研究，重点探讨在高温高频疲劳载荷长时作用下铸造孔洞、表面氧化、碳化物等非连续界面附近材料的累积响应机理和退化规律，揭示缺陷调控对材料高温超高周疲劳性能的影响规律，建立基于缺陷和显微组织的疲劳裂纹萌生物理模型、裂纹早期扩展的力学模型和寿命预测模型，为先进航空发动机的长寿命安全服役夯实超高周疲劳方面的理论基础。

In this project, experiments will be conducted to determine the effects of temperature, load frequency, defects and oxidation on very high cycle fatigue (VHCF) behavior of nickel base single crystal DD6 for advanced aeroengine high-pressure turbine blades. The mechanism of crack initiation and early growth for VHCF at elevated temperatures, frequency dependence will be investigated. The cumulative response mechanism and degradation rule of the materials near the discontinuous interface such as casting porosity, surface oxidation and carbides under elevated temperature and high frequency fatigue load for long time are emphatically discussed. In order to reveal the control parameters of VHCF properties, the influence of defects on the high-temperature VHCF property will be emphasized. Finally, models for crack initiation, early growth and life prediction in VHCF regime will be proposed. This study is expected to establish theoretical basis of long life safety service of key components for advanced aeroengine.