Al2O3陶瓷涂层尖端受载下的声发射信号参量分析
Characteristic parameter analysis of acoustic emission signals under tip loading on Al2O3 ceramic coating
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摘要: 为了考察再制造零件涂层结合强度检测仪评价涂层结合强度的可行性,以Al2O3陶瓷涂层为研究对象,在涂层表面进行压入试验,提取并分析了试验过程中声发射信号中的幅度、计数、能量与有效值电压(RMS)特性参数的时间分布曲线,读取了声发射信号突变点的波形,观测了压痕处涂层截面微观形貌。结果表明,声发射信号出现明显突变时,涂层界面确实产生了开裂失效。采用此检测设备可以有效诱导、界定涂层界面的断裂失效,声发射信号可以作为涂层开裂的临界判据,其中幅度的时间分布更能体现出Al2O3陶瓷涂层在压入过程中的裂纹萌生至涂层断裂的扩展过程;能量值对涂层的失效更为敏感,最为适合评价涂层的结合强度。Abstract: In order to investigate the feasibility of the detector on evaluating the bonding strength of surface coatings on the remanufactured components,Al2O3 ceramic coating,as the research objects,were fabricated,and then were tested by superficial indentation testing.The time distribution curves of acoustic emission(AE) primary parameters including amplitude,count,energy and root mean square value(RMS) were extracted and analyzed.The waveforms of inflection point were read.And the sectional morphologies of indentation points were observed by scanning electronic microscope.The results of the experiments indicated that the interfaces occurred surely fracture failure when there was a significant AE signal mutations.This testing equipment could effectively induce and define coatings cracking failure. And AE signals could be an effective criterion to detect the coating failure.There into,the amplitude possessed a better capability to indicate the crack propagation process.The energy was more sensitive of the fracture phenomena and appropriate for evaluating the bonding strength.