Finite Element Analysis on Influence of TiO₂ Content in Transition Layer on Residual Stress in Plasma Spraying of 2197 Al-Li Alloy/Al₂O₃-TiO₂ Composite Coating

By using finite element method, NiAl binding layer, transition coating with different TiO₂ content and Al₂O₃-5%TiO₂ ceramic layer were simulated on the substrate surface of 2197 Al-Li alloy.The differences in residual stress in the overall model caused by Al₂O₃-10% TiO₂, Al₂O₃-20%TiO₂, Al₂O₃-30%TiO₂ and Al₂O₃-40%TiO₂ transition coating were analyzed and the effect of Al₂O₃-TiO₂ transition layer with different TiO₂ contents on the residual stress of plasma coating was studied.The results show that among them, the TiO₂ content in the transition layer has the greatest influence on the radial residual stress at the interface between the transition layer and the bond layer.With the increase of TiO₂ content in transition layer from 10% to 40%, the maximum radial residual tensile stress increases from 1.74 MPa to 5.33 MPa.TiO₂ content in the transition layer has little effect on the residual stress between the transition layer and the top layer.The maximum radial residual stress appears at the axial position of the ceramic surface.The maximum axial residual stress is concentrated near the edge of the coating bonding interface.In industry, it is recommended to use the transition layer with less TiO₂ content to reduce the residual stress of the spraying coating and improve the strength of the spraying coating.