氧化层非均匀增长对热障涂层应力分布的影响

Effects of oxide layer non-uniform growth on thermal barrier coating stress distribution

利用扫描电镜对不同氧化程度的热障涂层(TBCs)进行观察,分析发现热生长氧化层(TGO)各部位并非均匀增长。假设热生长氧化层的形状为正弦曲线,用统计方法处理扫描电镜图片可以得到热生长氧化层的基本几何参数。由此建立单波形二维轴对称有限元模型,计算并分析了非均匀增长模型的应力状况。结果表明:相同温度下,非均匀增长模型的轴向、剪切和Mises应力分量的变化趋势与均匀增长模型的对应趋势一致;但是非均匀增长模型的各个应力分量最大值均小于均匀增长模型的应力分量最大值。

Thermal barrier coatings（TBCs）with different oxidation time were observed using scanning electron microscopy.It was found that the thermally grown oxide layers（TGO）did not grow uniformly.Assuming that the shape of the thermally grown oxide layer was sinusoidal,the basic geometrical parameters of the thermally grown oxide layer could be obtained by statistical processing of scanning electron micrographs.Then the two-dimensional axisymmetric finite element models of single waveform were established and the stress states were calculated and analyzed.Results showed that the trend of the axial,shear and Mises stress components of the non-uniform growth model were consistent with those of the uniform growth model under the same temperature,but the maximum stress components of the inhomogeneous growth model were smaller than those of the homogeneous growth model.