摘要
航空发动机涡轮叶片试车后存在热障涂层剥落现象,通过对涂层剥落叶片及对比件进行宏观及微观观察、显微硬度、化学分析等测试,结合生产工艺全流程的调查分析及验证试验,找到叶片涂层剥落的根本原因。结果表明:叶片热障涂层剥落系物理气相沉积过程中设备抽气速率下降,造成炉内真空度下降,从而导致陶瓷层柱状晶组织与正常组织存在明显差异,且陶瓷层与金属粘接层存在一定厚度的TGO层,使得结合力下降。试验发现,通过改变真空度的高低,可得到两种不同的柱状晶组织;真空度高时,柱状晶呈羽毛状或麦穗状生长,硬度值高;真空度低时,柱状晶根部疏松,呈层状分布,硬度值低。这表明真空度对陶瓷层的组织和性能有一定的影响。
It is found that the thermal barrier coating has peeled off the blade after test running.Macro and micro observation,micro-hardness,chemical analysis were carried out to analyze the failure blade and contrast parts.At the same time,the whole production process was investigated carefully and doing the proof test.Finally,the root cause of the fracture coating was founded.The results show that the peeling of thermal barrier coating on the blade was caused by the following reasons.The pumping rate of the equipment decreased,resulting in a decrease in the vacuum degree in the furnace.Therefore,a significant difference between the columnar crystal structure of the ceramic layer and the normal structure was created,and there was a TGO layer with certain thickness formed between the ceramic layer and the metal bonding layer.Aforementioned factors led to the declined affinity.Through changing the vacuum degree in the furnace,it can produce two kinds of columnar crystal.When the vacuum degree is high,the columnar crystal is the featheriness or ear of wheat shape and the micro-hardness is high.Whereas,the columnar crystal shows the“lamellar”and the foot is loosen,micro-hardness is low.The vacuum degree has impacted on the thermal barrier coating of microstructure and property.
作者
李卫军
魏磊
刘国良
LI Wei-jun;WEI Lei;LIU Guo-liang(AECC Aviation Power Co.,Ltd.,Xi’an 710021,China)
出处
《失效分析与预防》
2022年第1期41-45,共5页
Failure Analysis and Prevention
关键词
热障涂层
物理气相沉积
柱状晶
真空度
微观形貌
thermal barrier coating
physical vapor deposition
columnar crystal
vacuum
micro-structure
