Residual stress evolution and failure behaviour of High-Temperature Radar-Infrared compatible stealth coatings under thermal cycles considering interface morphology

Résumé fourni par la source

Stealth performance has become a core capability of modern advanced aircraft, receiving widespread attention and rapid development in recent years. In this study, an ultra-thin high-temperature radar-infrared compatible stealth coating (HRISC) with thermal barrier coating was designed and prepared, and its stealth performance at high temperature and failure behavior under thermal cycling loads were tested. Considering residual stress as the primary driving force for crack nucleation and propagation in the coating, the impact of interface morphology on residual stress distribution of HRISC system during thermal cycling was investigated using the finite element method. Both the dynamic growth of thermally grown oxide (TGO), and the temperature-dependent creep and plasticity characteristics of the coating were considered in the finite element model. The effects of the amplitude and wavelength of TGO and dielectric layer (DL) on the residual stress distribution at the failure interfaces under thermal cyclic loading were analyzed. Results showed that the maximum interfacial stress in the coating system occurred at the bonding layer /TGO interface, with wavelength and number of cycles exerting the most significant influence on the stress distribution. A stress concentration zone appeared near the DL / thermal barrier ceramic layer 1 interface, and the maximum stress in the zone increased with the increase in amplitude and the decrease in wavelength. Cracks would extend from the peak of the DL layer to this zone, which was consistent with the experimental phenomenon. The results of this work can provide guidance for the structural design and failure behavior evaluation of compatible stealth coatings.

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