Abstract：
The TC/BC interface morphology in APS TBC is one of the important factors leading to crack propagation and coating failure. Long cracks are found near the bulge on the TC/BC interface. In this study, the TBC model with the bulge on the interface is developed to explore the influence of the bulge on the coating failure. Dynamic TGO growth and crack propagation are considered in the model. The effects of the bulge on the stress state and crack propagation in the ceramic layer are examined. Moreover, the effects of the distribution and number of bulges are also investigated. The results show that the bulge on the interface results in the redistribution of local stress. The early cracking of the ceramic layer occurs near the top of the bulge. One bulge near the peak or valley of the interface leads to a coating life reduction of about 75% compared with that without a bulge. The increase in the number of bulges further decreases the coating life, which is independent of the bulge location. The results in this work indicate that a smooth TC/BC interface obtained by some possible surface treatments may be an optional scenario for improving coating life.
摘要：
APSTBC中TC/BC界面形貌是导致裂纹扩展和涂层失效的重要因素之一。在TC/BC界面上的凸起附近发现长裂纹。在这项研究中,建立了具有界面凸起的TBC模型，以探讨凸起对涂层失效的影响。模型中考虑了动态TGO扩展和裂纹扩展。研究了凸起对陶瓷层中应力状态和裂纹扩展的影响。此外，还研究了凸起的分布和数量的影响。结果表明，界面上的凸起导致局部应力的重新分布。陶瓷层的早期开裂发生在凸起的顶部附近。与没有凸起的涂层相比,在界面的峰或谷附近的一个凸起导致涂层寿命减少约75%。凸起数量的增加进一步降低了涂层寿命，这是独立的凸起位置。这项工作的结果表明，通过一些可能的表面处理获得的光滑的TC/BC界面可能是提高涂层寿命的可选方案。
