| HAN Zhi-yong,ZHANG Tao,GUO Wan-sen,WANG Zhe,DING Kun-ying.Effects of Service Environment on Failure Modes of Thermal Barrier Coatings on Turbine Guide Blades[J],52(4):261-271 |
| Effects of Service Environment on Failure Modes of Thermal Barrier Coatings on Turbine Guide Blades |
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| DOI：10.16490/j.cnki.issn.1001-3660.2023.04.023 |
| KeyWord:turbine guide blade thermal barrier coating regionalization temperature field failure mode |
| Author | Institution |
| HAN Zhi-yong |
Tianjin Key Laboratory for Civil Aircraft Airworthiness and Maintenance, Civil Aviation University of China, Tianjin , China |
| ZHANG Tao |
Tianjin Key Laboratory for Civil Aircraft Airworthiness and Maintenance, Civil Aviation University of China, Tianjin , China |
| GUO Wan-sen |
Tianjin Key Laboratory for Civil Aircraft Airworthiness and Maintenance, Civil Aviation University of China, Tianjin , China |
| WANG Zhe |
Tianjin Key Laboratory for Civil Aircraft Airworthiness and Maintenance, Civil Aviation University of China, Tianjin , China |
| DING Kun-ying |
Tianjin Key Laboratory for Civil Aircraft Airworthiness and Maintenance, Civil Aviation University of China, Tianjin , China |
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| Abstract: |
| As the service environment of turbine guide vanes becomes more and more severe, more and more attention is paid to the thermal barrier coating failure problem. However, there are still some shortcomings in the structure and performance evolution and failure behavior of the surface thermal barrier coating of turbine guide blades under real operating conditions. It is necessary to further improve the failure mechanism of the surface thermal barrier coating of turbine guide blades, and it is important to study different damage behaviors to establish a regionalized failure mode of the thermal barrier coating. In this paper, UG software was used to model and FLUENT software was used to calculate the three-dimensional conjugate heat transfer of a civil aero-engine turbine guide blade under service environment. Corresponding constant temperature test was conducted by collecting the temperature of flow field in each region. And scanning electron microscope and energy spectrometer were used to investigate the macro-microscopic morphology of the thermal barrier coating. The thermal barrier coating was subject to 0 h, 20 h, 50 h and 100 h of constant temperature oxidation. The macro and micro morphology of thermal barrier coating, the erosion behavior of calcium-magnesium-aluminosilicate (CMAS) and the growth of thermal growth oxide (TGO) as well as the changes of porosity and hardness were measured with scanning electron microscopy and energy spectroscopy. A new regional failure assessment model of thermal barrier coating was established by introducing coating damage coefficients, and the effects of service environment on the regionalized failure mode of the thermal barrier coating of aero-engine turbine guide blades was comprehensively analyzed. The results showed that after 8 500 hours of service, the failure mode of the thermal barrier coating on the surface of the turbine guide blade varied according to the local differences of the service environment. The highest temperature in the leading edge of the blade was 1 501.69 K, where severe low melting point oxide erosion occurred, resulting in the porosity of the ceramic layer dropping to 11.909% and the TGO equivalent thickness grew to 1.870 μm; The lowest temperature in the trailing edge was 980.46 K, where no CMAS erosion was observed and the porosity of the ceramic layer dropped to 13.701% and the TGO equivalent thickness grew to 2.676 μm. The average temperature of leaf basin and leaf back surface was 1 363.47 K and 1 264.14 K, respectively, and mild low melting point oxide erosion occurred, the porosity of ceramic layer decreased to 12.176% and 13.371%, respectively. The TGO equivalent thickness grew to 6.959 μm and 3.742 μm, respectively. The complex operating conditions of the final turbine guide blade led to different structural evolution and failure modes of the coating in each region. The leading edge of the blade coating had increased the oxygen diffusion activation energy to QO=105.6 kJ/mol due to severe CMAS erosion. The sintering damage factor is 1.021 2 and the TGO damage factor is 0.269 1, and the main failure mode is ceramic layer sintering. The sintering damage factor of the blade trailing edge coating is 0.599 8 and the TGO damage factor is 0.385 0, and the failure mode is a joint failure with sintering as the main factor and TGO thickening as the secondary factor. The sintering damage coefficient of leaf basin and leaf back coating is 0.958 6 and 0.677 4 respectively, and the TGO damage coefficient is 1.001 6 and 0.538 4 respectively, the main failure mode is the joint failure of sintering and TGO thickening. According to the above regionalized failure mode of turbine guide blade thermal barrier coating, each area of the blade can be treated with different modes of damage resistance in the future to provide direction for the subsequent life extension of turbine guide blades. |
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