Thermal shock failure is the most common type occurring in service. The thermal shock life is overestimated and the failure process of thermal barrier coatings (TBCs) is still not clear due to lack of environmental simulator and the real-time detection methods. In this work, the damage evolution and failure mechanism of EB-PVD TBCs coated on a turbine vane under thermal shock is studied by acoustic emission combined with digital image correlation (DIC) method. Four damage modes are discriminated by spectrum of the acoustic emission signals, which are surface vertical cracks (200–220 kHz), sliding interfacial cracks (300–325 kHz), opening interfacial cracks (400–450 kHz) and substrate deformation (90–110 kHz). The principal strain of TBCs surface varies from compressive strain to tensile strain with increasing the thermal shock cycles. Furthermore, the thermal shock life is 710 cycles, and the exfoliation area is located in the middle of the leading edge. The failure mechanism is the propagation and coalescence of surface and interfacial cracks during the cooling stage due to the huge thermal gradient and stress concentration around the film holes.

热冲击失效是服务中最常见的类型。由于缺少环境模拟器和实时检测方法，热冲击寿命被高估，并且热障涂层（TBC）的失效过程仍然不清楚。通过声发射结合数字图像相关（DIC）方法研究了涡轮叶片上EB-PVD TBCs在热冲击下的损伤演化和破坏机理。根据声发射信号的频谱来区分四种损坏模式，分别是表面垂直裂缝（200–220 kHz），滑动界面裂缝（300–325 kHz），开口界面裂缝（400–450 kHz）和基底变形（90– 110 kHz）。随着热冲击循环的增加，TBCs表面的主应变从压缩应变变化到拉伸应变。此外，热冲击寿命为710个循环，剥落区域位于前缘的中间。失效机理是由于巨大的热梯度和膜孔周围的应力集中，在冷却阶段表面和界面裂纹的扩散和聚结。