Finite element simulation of residual stress of double-ceramic-layer La ₂Zr ₂O ₇/8YSZ thermal barrier coatings using birth and death element technique

In this paper, the residual stress of double-ceramic-layer (DCL) La ₂Zr ₂O ₇/8YSZ thermal barrier coatings (TBCs) fabricated by atmospheric plasma spraying (APS) was calculated by finite element simulation using birth and death element technique. The residual stress was composed of two parts, i.e. the quenching stress and the thermal stress. The simulation results indicated that the surface and the edge of interface are often the positions of stress concentration. The DCL La ₂Zr ₂O ₇/8YSZ has lower residual stress compared with that of the single-ceramic-layer (SCL) 8YSZ TBCs with the same thickness. In addition, the influence of defects on the residual stress has been calculated and discussed using finite element method combined with Computational Micro-Mechanics (CMM). As the DCL TBCs has better thermal insulation effect, sintering resistance ability and lower residual stress compared with that of the SCL 8YSZ at the same time, it was expected to be an ideal candidate material for the application in the future.