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Effect of shaped film cooling hole manufacturing defects on the high cycle fatigue behavior of a Ni-based single crystal superalloy
  • +4
  • Yue Wang,
  • Rong Jiang,
  • Mo Chen,
  • Xiaoyu Li,
  • Xu-ping Lu,
  • Haiyong Zha,
  • Yingdong Song
Yue Wang
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering
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Rong Jiang
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering

Corresponding Author:rjiang@nuaa.edu.cn

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Mo Chen
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering
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Xiaoyu Li
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering
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Xu-ping Lu
China Gas Turbine Establishment
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Haiyong Zha
China Gas Turbine Establishment
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Yingdong Song
Nanjing University of Aeronautics and Astronautics College of Energy and Power Engineering
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Abstract

The complex geometrical configuration of shaped film cooling holes (FCHs) enhances the cooling efficiency of turbine blades, while the stress concentration at the shaped FCH edge and the manufacturing defects usually leads to high cycle fatigue (HCF) failure under the service conditions. In this study, HCF tests at 900 ℃ were conducted on DD6 single crystal superalloy containing dustpan and dovetail FCHs. The effect of shaped FCHs and manufacturing defects on the HCF strength was investigated, and the related HCF failure mechanism was analyzed using SEM, EDS and EBSD. The results show that manufacturing defects including pores, recast layer and polycrystalline microstructure region exist around the shaped FCH edge. The stress concentration of defective pores promotes the plastic deformation and oxidation at high temperatures, leading to crack initiation. The fatigue strength is 318.89 MPa for the dustpan FCH specimen and is 304.93 MPa for the dovetail FCH specimen, and both of them are lower than that of the traditional cylindrical FCHs due to the existence of the manufacturing defects, indicating the necessity to consider the effect of manufacturing defects in the evaluation of the HCF strength of components with the shaped FCHs.
06 Jan 2025Submitted to Fatigue & Fracture of Engineering Materials & Structures
08 Jan 2025Submission Checks Completed
08 Jan 2025Assigned to Editor
12 Jan 2025Reviewer(s) Assigned