Research And Numerical Simulation Of Thermal Mechanical Behavior Of Thermal Barrier Coating Micromorphology

Thermal barrier coatings have been widely applied in aerospace,gas and chemical industry because of their excellent performance.Thermal barrier coating is a surface coating formed by Spray low thermal conductivity material on hot end of turbine by a certain preparation process.Thermal barrier coatings have high heat insulation and high temperature resistance,which improves the working temperature of the hot end of turbine.The service environment of the thermal barrier coating is very complicated and the thermal barrier coating is not only affected by the external high temperature and high pressure,but also has large thermal stress in the interior of the coating because the material has different thermal physical properties.At present,in order to get higher gas efficiency and larger engine thrust ratio,it is necessary to improve the working temperature of the thermal barrier coatings.The original coating materials and preparation technology are difficult to improve the working temperature of the thermal barrier coating.The exploration of new materials and improvement of preparation technology has become the focus of current research.The preparation process determines the microstructure of the coating.It is necessary to study the Influence of thermal barrier coating microstructure on its thermal and mechanics behavior,so as to direct the improvement of the coating preparation process.By analyzing the micromorphology of thermal barrier coatings with better thermal insulation and mechanical properties,we can provide references for improving the preparation process of coatings.The thermal barrier properties and mechanical properties of the thermal barrier coatings are related to the microstructure of the coating: The existence of the pores in the coating affects the thermal insulation properties of the coating and the stress distribution in the coating;The change of interface morphology affects the bonding strength of different phases in the coating,and then affects the failure and service life of the coating.In this paper,through theoretical analysis and finite element simulation,A random pore model is established to analyze the effect of pores in the coating on the thermal insulation performance of the coating and to explore the relationship between the interface morphology and the stress distribution at the interface.Simulation results found:1.Under the condition of uniform pore radius,the simulation results show that within a certain range,the larger the porosity is,the better the heat insulation performance of the coating is;Under the condition of uniform porosity,the results show that in a certain degree,the larger the pore radius is,the better the heat insulation performance of the coating is.2.In the case of the same porosity and the same pore radius,within a certain range,The farther the pores are from the surface of the ceramic layer in a certain range,the better the thermal insulation performance of the coating;the change in the distance between the pores and the interface will not affect the thermal insulation of the coating.3.Comparing the pores of different morphologies,the results show that the pores have different obstructing effects on the heat flow.In a certain degree,the thin and elongated pore is beneficial to the improvement of the thermal insulation performance of the coating.4.Compared with the sinusoidal interface and the continuous convex interface model,the stress concentration at the convex interface of the unilateral convex interface model with a certain interval is weakened.5.In a certain degree,the shorter the distance between the pores and the interface,the more severe the influence on the stress distribution at the interface of the coating.The greater the porosity,the greater the influence on the stress at the interface of the coating.The change of the distance between the interface of the pore and the coating has no effect on the thermal insulation performance of the coating,and the pore has a greater influence on the stress distribution of the interface.Therefore,when preparing the coating,the pore should be kept away from the coating interface.