Abstract: A laser shock processed(LSPed) thermal barrier coating model was established by changing the growth rate and morphology of thermally grown oxide (TGO), and the interfacial stress of the LSPed coating was simulated in comparison with those of the non-LSPed coating, so as to analyse the effect of laser modification on the high-temperature thermal cycling of the thermal barrier coating from the view of the stress evolution, and the cohesion units at the TC/TGO interface was introduced to study the effect of laser modification on the interfacial crack of the thermal barrier coating. The results show that for the same TGO morphology, the stress value of LSPed specimens is smaller than that of Non-LSPed specimens on the TGO surface, and the laser modification reduces the risk of fold warping, layer cracking, and shear damage in this region. At the TGO/BC interface, the stress value of LSPed specimens in the pre-oxidation period is larger, but in the late stage of the oxidation period, the stress values of Non-LSPed and LSPed specimens are close to each other, suggesting that the effect of LSP modification on the stress at the TGO/BC interface is relatively small. Under different TGO morphologies, the overall stress of LSPed specimens is smaller than that of Non-LSPed specimens, indicating that LSP modification can effectively reduce the stress value of the coating interface. After 35 thermally cycles, cracks appear at the wave peak position of the TC/TGO interface in the Non-LSPed specimen. As the number of cycles increases, the cracks extend towards the wave valley. However, no cracks appear in the LSPed specimen after 50 thermal cycles.

Key words: laser shock processing, thermal barrier coatings, cohesive element, crack, stress evolution, finite element simulation