| HU Shuai,FENG Yong-jun,LI Wei-han,HU Su-ying,GONG Xue,XIE Zhi-wen.Numerical Simulation of Residual Thermal Stress Distribution and Thermal Stability of LaMgAl11O19 Thermal Barrier Coating during Annealing[J],51(6):275-282 |
| Numerical Simulation of Residual Thermal Stress Distribution and Thermal Stability of LaMgAl11O19 Thermal Barrier Coating during Annealing |
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| DOI：10.16490/j.cnki.issn.1001-3660.2022.06.025 |
| KeyWord:thermal barrier coating annealing residual thermal stress stress gradient thermal stability numerical simulation |
| Author | Institution |
| HU Shuai |
School of Mechanical Engineering and Automation, University of Science and Technology Liaoning, Liaoning Anshan , China |
| FENG Yong-jun |
School of Mechanical Engineering and Automation, University of Science and Technology Liaoning, Liaoning Anshan , China |
| LI Wei-han |
School of Mechanical Engineering and Automation, University of Science and Technology Liaoning, Liaoning Anshan , China |
| HU Su-ying |
School of Mechanical Engineering and Automation, University of Science and Technology Liaoning, Liaoning Anshan , China |
| GONG Xue |
College of Aerospace Engineering, Shenyang Aerospace University, Shenyang , China |
| XIE Zhi-wen |
School of Mechanical Engineering and Automation, University of Science and Technology Liaoning, Liaoning Anshan , China |
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| Abstract: |
| This work aims to explore the distribution of residual thermal stress in LaMgAl11O19 thermal barrier coating during annealing and its effect on the thermal stability of thermal barrier coating. Based on the physical model of LaMgAl11O19/ YSZ double thermal barrier coating prepared by plasma spraying, the numerical simulation model was established by Abaqus. Through the coupled calculation of temperature displacement, the distribution of residual thermal stress in LaMgAl11O19 thermal barrier coating at different annealing temperatures was systematically analyzed. The microstructure of the coating surface and section before and after annealing was observed by SEM experiment. According to the results of numerical simulation and SEM image of the coating, the influence of residual thermal stress on the thermal stability of LaMgAl11O19 thermal barrier coating was analyzed, and the influencing factors of coating crack damage and failure were explored. The numerical simulation results show that the residual thermal stress in LaMgAl11O19 thermal barrier coating is mainly radial stress, which is much larger than the axial stress and shear stress. During annealing, the radial residual thermal stress increases slowly to the maximum in the range of 0~2.4 mm, but decreases sharply in the range of x=2.4 mm to the radial edge. After annealing, the concentrated stress appears at the radial edge of the coating, reaches the maximum tensile stress at the radial distance x=2.6 mm, and decreases rapidly to compressive stress. The radial residual thermal stress gradients are 0.334 GPa, 0.369 GPa, 0.389 GPa and 0.391 GPa at 900 ℃, 1 000 ℃, 1 100 ℃ and 1 200 ℃, respectively. The radial residual thermal stress gradients are 0.104 MPa, 0.148 MPa, 0.203 MPa and 0.260 MPa after annealing, respectively. From the SEM images of the surface and cross section of the annealed coating, it is found that the main damage of the internal crack of LaMgAl11O19 thermal barrier coating is axial crack. During the annealing process, the radial residual thermal stress of LaMgAl11O19 thermal barrier coating has a sudden change of tensile and compressive stress at the radial edge, and the stress gradient increases with the increase of annealing temperature. The results show that there is a large radial residual thermal stress in the annealing process of thermal barrier coating, and the stress value is dominant, which is the main reason for the generation and propagation of axial cracks in thermal barrier coating. |
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