A study on failure of double-layer thermal barrier coatings subjected to uniaxial compression tests using acoustic emission analysis and digital image correlation
A study on failure of double-layer thermal barrier coatings subjected to uniaxial compression tests using acoustic emission analysis and digital image correlation
复制标题
使用声发射分析和数字图像相关性研究单轴压缩试验双层热障涂层的失效
DOI：
10.1016/j.prostr.2018.12.252
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
Oechsner M
中科院分区：
文献类型：
--
作者：
Adam M;Kontermann C;Oechsner M
研究了单轴压缩基体载荷下双层热障涂层的失效行为和断裂过程。制造含有低孔隙率和高孔隙率（LP、HP）GZO 的涂层系统，以检查微观结构对失效行为和应变能的影响。 YSZ-HP 单层系统作为参考。所有陶瓷涂层均通过大气等离子喷涂 (APS) 沉积在由 CoNiCrAlY (LCO-22) 涂层、镍基单晶高温合金 (PWA 1483) 制成的圆柱形棒和涡轮叶片形样品上。在压缩测试之前，进行了 1050 °C 的等温预氧化和 100、500 和 1.500 小时的停留时间，以及 50 至 1050 °C 之间最多 500 个循环的循环退火测试，以研究热老化对失效应变能的影响。原位声发射 (AE) 测量提供有关基材压缩载荷下失效过程的定量信息。立体摄像系统监测三维位移和表面断裂过程。对于喷涂涂层，所研究的 GZO/YSZ 系统的失效应变与参考的单层 TBC 相当。 AE 分析表明涂层在早期阶段失效，并且随着停留时间的增加，热老化后基材负载减少。因此，预氧化导致所有研究的涂层系统中的失效应变值降低。数字图像相关性 (DIC) 表明，喷涂后的 GZO/YSZ 涂层的失效行为与参考的 YSZ 系统类似。然而，对于预氧化涂层观察到不同的行为，其中主要发生 GZO 的裂纹和剥落。
The failure behavior and fracture process of double-layer thermal barrier coatings under uniaxial compressive substrate loading has been investigated. Coating systems containing GZO with low and high porosity (LP, HP) were fabricated to examine the influence of microstructure on failure behavior and strain energy. An YSZ-HP single-layer system serves as a reference. All ceramic coatings were deposited via atmospheric plasma spraying (APS) on cylindrical rods and turbine blade-shaped specimens made from CoNiCrAlY (LCO-22) coated, nickel-based, single crystal superalloy (PWA 1483). Prior to compression tests, isothermal pre-oxidation at 1050 °C and dwell-times of 100, 500 and 1.500 hours, as well as cyclic annealing tests between 50 and 1050 °C up to 500 cycles were performed, to study the effects of thermal ageing on strain energy to failure. In-situ acoustic emission (AE) measurements provides quantitative information about the failure processes under compressive substrate loading. A stereo camera system monitors the three-dimensional displacements and the surface fracture processes. For as-sprayed coatings, strain to failure of the investigated GZO/YSZ systems is comparable to the referenced single-layer TBC. AE analysis indicates coating failure at earlier stages and less substrate loads after thermal ageing with increasing dwell-time. Consequently, the pre-oxidation leads to reduced strain to failure values in all investigated coating systems. Digital image correlations (DIC) suggests that the failure behavior of as-sprayed GZO/YSZ coatings is similar to the referenced YSZ system. However, a different behavior was observed for pre-oxidized coatings, where cracking and spallation of GZO occurs predominantly.