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| Effect of Thermal Barrier Coatings on High Cycle Fatigue Properties of DD6 Single Crystal Superalloy |
| Received:October 31, 2018 Revised:January 25, 2019 |
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| DOI：10.7643/ issn.1672-9242.2019.01.008 |
| KeyWord:DD6 second generation single crystal superalloy electron beam physical vapor deposition thermal barrier coatings high cycle fatigue property fracture mode |
| Author | Institution |
| TIAN He |
Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material, Beijing Institute of Aeronautical Materials, Beijing , China |
| HE Li-min |
Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material, Beijing Institute of Aeronautical Materials, Beijing , China |
| MU Ren-de |
Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material, Beijing Institute of Aeronautical Materials, Beijing , China |
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| Abstract: |
| Objective To study on the effect of electron beam physical vapor deposition (EB-PVD) thermal barrier coatings (TBCs) on the high cycle fatigue properties of single crystal superalloy and provide a technical basis for application of thermal barrier coatings on turbine blades. Methods YSZ thermal barrier coatings were prepared by vacuum arc plating and EB-PVD and high cycle fatigue tests for the coatings samples were carried out at 900 ℃. The surface and fracture morphologies of the tested samples were observed and analyzed with scanning electron microscope (SEM). Results Under the condition of 900 ℃ and 380 MPa, the fatigue cycles of DD6 single crystal alloy with TBCs were more than 107 times without breaking. On the other hand, the fatigue cycles of DD6 superalloy exceeded 106 times when the load was 420 MPa. By analyses of the fracture morphologies of DD6 single crystal alloy, the coated samples were still destroyed by the common slip and dissociation of DD6 single crystal alloy. Conclusion Although the vertical cracks first appeared in the bond coating of the coated samples in high cycle fatigue property, the phenomenon of oxidative passivation occurs during the propagation of the cracks. After that, the cracks in the DD6 matrix extends from the surface to the interior along the normal slip direction. The fatigue cracks of the coated samples are not directly formed by micro cracks in the coatings, so thermal barrier coatings have little effect on the high cycle fatigue properties of single crystal superalloy. |
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