Finite Element Analysis Of Failure Mechanism Of EB-PVD Thermal Barrier Coatings Based On Single Particle Erosion

Thermal barrier coatings(TBCs)are widely used in aero engines due to their excellent performance on heat resistance,oxidation resistance,corrosion resistance and wear resistance.However,the engine will inevitably be subjected to the erosion of hard particles from the outside or inside the combustion chamber during the service time.This effect will cause the coatings to peel off ahead of time and affect the overall performance of the engine.The erosion effect has a greater influence on the coatings prepared by the electron beam physical vapor deposition(EB-PVD).Therefore,the erosion of the EB-PVD thermal barrier coatings is mainly studied in this paper.Because there are many factors that affect the coatings erosion failure,it is difficult to carry out in experiment.In order to simplify the problem,the erosion model of EB-PVD thermal barrier coatings under single particle erosion was established by finite element method.The effects of different influencing parameters on coatings erosion failure were simulated.Finally,the erosion damage mechanism diagrams of the thermal barrier coatings are established and the optimization of the thermal barrier coating is proposed.The main research contents of this article are as follows:Firstly,the ABAQUS finite element model was established based on the structural features of EB-PVD TBCs.The material model was selected based on its real structural features.Hence,the columnar crystals were represented by the GTN model and the gaps of the columnar crystals were represented by the low-density foam model.One of the typical characteristics of the EB-PVD TBCs at high temperature erosion is the kink band.The results of the analysis of the shear bands show that there is approximately a linear relationship between the energy of the erosion particle with its angle,so does its length.Secondly,the erosion failure mechanism diagrams were established according to the experience criteria.Erosion particle parameters(such as erosion speed,angle,etc.)and coating columnar crystal parameters(such as columnar crystal width and columnar crystal material parameters)were considered.And the failure mechanism maps under different influencing parameters were established respectively.It shows that the faster the particle impacts,the bigger the particle radius has,the larger the angle of the incidence has,the coatings are easier to form crack.The relevant parameters of the TBCs itself also have an effect on the erosion failure of the coating.Correspondingly,the smaller width the columnar crystal and the inter-columnar crystal are,the more likely the cracks are formed.Also,the smaller Young modulus and yield.strength the columnar crystal has,the easier the coatings to crack.The analysis of the stress field of the coating summarizes the cracking forms of the coating under different conditions.The effect of these material parameters on the erosion resistance of the coating were analyzed and compared.All of these will give corresponding suggestions and basis for process optimization of TBCs.Thirdly,the reliability of each parameter on the erosion failure of the TBCs was evaluated by Monte Carlo method.The influence of these parameters on the erosion failure was evaluated by the sensitivity analysis method.It was found that the erosion particles had a greater influence on the erosion failure of the coating than the coatings’parameters However,continuous optimization of the TBCs’ property process is still necessary.