Stress Generation Mechanism and Distribution Characteristics in Thermal Barrier Coatings

Thermal barrier coatings (TBCs) are widely used on the surface of aero-engine and other hot-end components due to its excellent high temperature resistance, wear resistance and corrosion resistance. As the service carrier of parts surface, thermal barrier coating is prone to surface cracking and interfacial peeling under the action of external thermal corrosion, thermal gradient stress and mechanical load stress, which is the key problem to limit the long-term use of thermal barrier coating. TBCs are made up of substrate, bonding coating and ceramic coating. Due to the different material properties of the substrate and coating, the distribution of interface stress-strain are different. TBCs still have some unresolved problems, for instance, how to realize coordinated deformation and understand the process of stress transfer of coating and substrate under loading. Therefore, the main purpose of this working is to study the stress transfer and distribution inside the TBCs. From the summary of the elastic-plastic stress model and damage stress model of TBCs, the stress distribution laws of coating interface are obtained. In the elastic-plastic stage, interface stress of TBCs is concentrated in one end, and the interface stress between substrate and bonding layer is about four times that of ceramic and bonding layer. With the increasing of load, the coating damage increases sharply. Interface normal stress of shear-lag model is more accorded with the quarter elliptic function, and interface shear stress takes an antisymmetric distribution. Stress distribution laws of TBCs provides theoretical basis for research on crack growth behavior under the function of load. © 2021, Materials Review Magazine. All right reserved.