基体曲率对热障涂层结合强度影响的无损检测研究

 针对复杂型面航空发动机涡轮叶片表面热障涂层(TBCs)的失效问题,采用交流阻抗谱(IS)法和洛氏硬度(RH)压痕法对比研究了制备在平板基体和曲率基体上,热障涂层在热循环过程中微观结构和界面结合强度的演变规律。交流阻抗谱法的结果表明:两种涂层试样的热生长氧化(TGO)层厚度及陶瓷层内裂纹数量均随着热循环时间增加而增长,但曲率试样的微观结构恶化速度更快;洛氏硬度压痕法的结果验证了经热循环后,曲率基体上热障涂层界面结合强度低于平板样品。

Influence of Substrate Curvature on the Bonding Strength of TBCs via Non-destructive Testing Research

In order to understand the failure mechanisms of the thermal barrier coatings(TBCs) applied on the aviation turbine engine blades with complex profiles,two kinds of TBC samples are prepared on plated and curvatured substrates,respectively.The evolutions of the microstructure and interface bonding strength of the TBCs during thermal cycling are investigated via AC impedance spectroscopy(IS) and Rockwell hardness(RH) indentation test.The AC IS results show that the themally grown oxide(TGO) layer thickness and micro-cracks grew with increasing thermal cycling for both samples,while an accelerated degradation is observed for the curvatured one.The RH indentation results confirm that the curvatured sample exhibites a relatively lower interface bonding strength than plated sample.