Abstract Experimental observations display that there exist two types of cracks induced by thermally grown oxide (TGO) in electron beam physical vapor deposition (EB-PVD) thermal barrier coatings (TBCs), which will lead to the coating spallation. Up to now, the failure mechanism induced by TGO is not clear. In this work, a finite element model with real thermally grown oxide morphology for crack propagation in TBCs is established by taking the advantage of commercial finite element package (ABAQUS) and image processing technique (Coreldraw). The coating failure mechanism under thermal mismatch stress is investigated. Present analysis and discussions show that the horizontal crack tends to propagate through the top coat layer toward the interface during the cooling stage, while the interface crack initiates at the points located in the middle region and then propagates in two side directions simultaneously, and mode II fracture plays a dominant role in the whole crack propagation process. Finally, two failure mechanisms of the TC/TGO interface are proposed in this paper.

中文翻译：

---

热应力下具有真实热生长氧化物形态的热障涂层的剥落

摘要 实验观察表明，电子束物理气相沉积（EB-PVD）热障涂层（TBCs）中存在两种由热生长氧化物（TGO）引起的裂纹，导致涂层剥落。到目前为止，TGO 引起的失效机制尚不清楚。在这项工作中，利用商业有限元包 (ABAQUS) 和图像处理技术 (Coreldraw) 建立了具有真实热生长氧化物形态的 TBC 裂纹扩展有限元模型。研究了热失配应力下的涂层失效机理。目前的分析和讨论表明，在冷却阶段，水平裂纹倾向于通过面漆层向界面传播，而界面裂纹从位于中间区域的点开始，然后同时向两侧扩展，II型断裂在整个裂纹扩展过程中起主导作用。最后，本文提出了 TC/TGO 接口的两种失效机制。