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

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.