带热障涂层单晶涡轮叶片涡流检测及损伤分析  

Eddy Current Testing and Damage Analysis of Single Crystal Turbine Blade With Thermal Barrier Coatings

作　　者：高志坤 张翔 卜嘉利 李夺 刘士佳 隋福利 GAO Zhikun;ZHANG Xiang;BU Jiali;LI Duo;LIU Shijia;SUI Fuli(AECC Shenyang Aeroengine Research Institute,Shenyang 110015,China)

机构地区：[1]中国航发沈阳发动机研究所,沈阳110015

出　　处：《航空制造技术》2024年第21期28-34,共7页Aeronautical Manufacturing Technology

摘　　要：针对工程上带涂层单晶涡轮叶片叶身微小裂纹缺陷缺少有效检测手段问题,探究并验证涡流检测方法的可行性。搭建一套涡流检测系统,对带热障涂层单晶涡轮叶片的不同深度缺陷进行检测识别,分析阻抗幅值变化规律。利用视频显微镜(DM)、扫描电子显微镜(SEM)、金相显微镜(OM)、能谱仪(EDS)开展检出缺陷叶片外观检查、解剖分析、金相检查、断口分析、成分分析等试验,确定涡流检出缺陷叶片异常信号的性质和产生原因。研制的涡流探头具有较高的灵敏度,能实现复杂曲面带热障涂层高压涡轮叶片试件预制缺陷的准确检测。随着缺陷深度增加,涡流阻抗信号幅值增加,当裂纹穿透叶片基体壁厚时,阻抗信号幅值达到最大。被检IC21高压涡轮叶片裂纹断口呈颗粒形貌,与原始铸造表面类似,未见明显的单晶断裂特征;叶片基体组织γ'相保持良好的立方化,表明叶片使用中未经历超温作用。搭建的涡流检测平台可有效检出带热障涂层单晶涡轮叶片约2.3 mm长、1.0 mm深的裂纹缺陷,研究成果有效填补了热障涂层下方基体微小裂纹缺陷检测方法空白;失效分析证实被检IC21高压涡轮叶片裂纹为原始再结晶缺陷导致的开裂,工艺上未明确要求抛修铸件的锥形凸起,影响了腐蚀检验时对再结晶缺陷的检测识别,这是导致该涡轮叶片开裂的主要原因。针对被检叶片裂纹缺陷,建议对叶片进行适当铸造和检测工艺优化,从而避免原始再结晶缺陷漏检。Aiming at the lack of effective detection methods for micro-crack defects in the blades of coated single crystal superalloy turbines,the feasibility of eddy current detection method was explored and verified.A set of eddy current detection system was established to detect and identify defects at different depths of IC21 single crystal superalloy blades with thermal barrier coating,and the impedance amplitude variation was analyzed.Video microscope(DM),scanning electron microscope(SEM),metallographic microscope(OM),and energy dispersive spectrometer(EDS)were used to carry out the appearance inspection,anatomical analysis,metallographic examination,fracture analysis,and composition analysis of the defective blades to determine the nature and cause of the abnormal signals detected by eddy current.The developed eddy current probe has high sensitivity and can accurately detect prefabricated defects on complex curved surface single crystal superalloy turbine blades with thermal barrier coating.With the increase of defect depth,the amplitude of eddy current impedance signal increases.When the crack penetrates the blade matrix wall thickness,the amplitude of impedance signal reaches the maximum.The crack morphology of the IC21 single crystal superalloy high pressure turbine blade is similar to that of the original casting surface,and no obvious single crystal fracture characteristics were observed.Theγ'phase of the blade matrix maintains a good cubed structure,indicating that the single crystal superalloy turbine blade has not experienced overtemperature during use.The eddy current testing platform can effectively detect about 2.3 mm×1.0 mm crack defects in turbine blades of single crystal superalloy with thermal barrier coating,and the research results effectively fill the gap in the detection method of micro-crack defects in the matrix under the thermal barrier coating.The failure analysis confirmed that the crack of the IC21 single crystal superalloy high pressure turbine blade was caused by the original recrystalli

关 键 词：IC21单晶高温合金 涡轮叶片 热障涂层 涡流检测 再结晶 原始裂纹 

分 类 号：V232.4[航空宇航科学与技术—航空宇航推进理论与工程]