Surface texture of substrates prepared by femtosecond laser for improving the thermal cycle life of TBCs

Abstract In this study, a substrate was surface textured using a femtosecond laser to prolong the service life of thermal barrier coatings (TBCs). The selected texture showed linear and diamond shapes. The effect of the texture shape on the thermal shock resistance of the TBCs was investigated by subjecting them to thermal shock cycles. The microstructure and composition of the TBCs were investigated using various characterisation methods. The mechanical properties of the TBCs were measured using the microindentation method. Based on the theory of elastoplastic mechanics, a three-dimensional finite element numerical model was established to analyse the effect of the two textures on the stress distribution of the TBCs. The results revealed that the linear-textured TBCs showed improved stress concentration at the coating interface when the coatings expanded or shrank, which resulted in an improvement in their thermal shock resistance. Therefore, the linear-textured TBCs showed excellent oxidation resistance, fracture toughness, and heat resistance as compared to the diamond-textured TBCs.