航空学报 > 2005, Vol. 26 Issue (1): 121-124

在高温蠕变环境中的热障涂层失效行为

高永栓, 陈立强, 宫声凯, 徐惠彬   

  1. 北京航空航天大学 材料科学与工程学院, 北京 100083
  • 收稿日期:2004-01-12 修回日期:2004-05-06 出版日期:2005-02-25 发布日期:2005-02-25

Failure Behavior of Thermal Barrier Coatings in Creep Environment

GAO Yong-shuan, CHEN Li-qiang, GONG Sheng-kai, XU Hui-bin   

  1. Department of Material Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083, China
  • Received:2004-01-12 Revised:2004-05-06 Online:2005-02-25 Published:2005-02-25

摘要: 对电子束物理气相沉积(EB-PVD)制备的由NiCoCrAlY粘结层和YSZ(YttriaStabilizedZirconia)陶瓷层组成的双层结构热障涂层,采用标准高温蠕变试验方法,研究了在高温、恒定外载荷作用下热障涂层中各层的形貌变化及裂纹的萌生、扩展,并探讨了涂层的失效过程和机理。垂直于试样轴向的断面观察表明,涂层在外力作用下氧化200h后层间裂纹非常明显,但几乎不发生在热氧化层(TGO)内,而是发生在陶瓷层与TGO层、TGO与粘结层之间,尤其发生在TGO与陶瓷柱状晶之间的等轴晶处。这种层间裂纹是在拉伸应力作用下,合金基体和粘结层发生径向收缩,而陶瓷层和TGO层的应变容限无法满足径向收缩而产生的。

关键词: 热障涂层, 电子束物理气相沉积, 高温蠕变, 失效机制

Abstract: High temperature creep testing is carried out to investigate the high temperature fatigue behavior of ceramic thermal barrier coatings(TBCs) prepared by electron beam- physical vapor deposition(EB-PVD). It has been observed that the cracks are mainly formed in the interface between TGO(Thermally Grown Oxidation) layer and the ceramic top coating, instead of in the TGO layer just often observed during thermal cyclic testing without loading. Such cracks can be considered to be caused by the creep of metallic substrate along loading direction and the shrink in diameter of sample.

Key words: TBCs, EB-PVD, TGO, creep, failure mechanism

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