摘要
针对电子束物理气相沉积(EB-PVD)热障涂层(TBCs)复杂结构的特点,选用Walker黏塑性本构模型实现对其高温力学行为的准确描述.选择具有叶片曲率特征的圆管试样,并借鉴实际发动机载荷特征进行数值分析.重点考虑EB-PVD热障涂层界面的形状以及热生长氧化层(TGO)厚度变化对应力场的影响.计算结果表明,直线型界面对EB-PVD热障涂层结构的应力场改变不大,而余弦界面对EB-PVD热障涂层的应力场改变的幅度可达2倍之多;热生长氧化层的出现导致陶瓷层界面处的应力绝对值增加;无论是循环至最高温度1 050℃还是冷却到100℃时,界面波谷始终受径向压应力,此处不易形成损伤,而波峰处的应力比较大,且其应力状态是损伤容易形成的部位,可以认为是陶瓷层失效与破坏的危险点.
Targeting the characteristics of thermal barrier coatings（TBCs）prepared by electron beam-physical vapor deposition（EB-PVD）of complex structure,the Walker viscoplastic constitutive model was used to realize the accurate description of the high temperature mechanical behavior of TBCs structure.Tube specimens with blade curvature feature were selected for numerical analysis with reference to the actual engine load characteristics.The effect of the interface shape and the thickness of thermal growth oxide（TGO）on stress field of EB-PVD coating were focused on.The calculating results show that the stress field of TBCs structure changes little at the linear interface,while the amplitude of stress field can be changed up to 2times at the cosine interface.The absolute value of stress at top coat increases due to the presence of the TGO.The valley at the interface is always subject to radial compressive stress no matter of circulation to the highest temperature 1 050℃ or cooling to100℃,therefore the valley is not easy to be damaged;while the stress at the peak is rela-tively large,furthermore,the stress state is easy to form part of the damage.As a result,the peak is a point for easy failure and destruction of the ceramic layer.
出处
《航空动力学报》
EI
CAS
CSCD
北大核心
2014年第7期1520-1526,共7页
Journal of Aerospace Power
关键词
热障涂层
热生长氧化层
界面
应力场
电子束物理气相沉积
thermal barrier coatings（TBCs）
thermal growth oxide（TGO）
interface
stress field
electron beam-physical vapor deposition（EB-PVD）
