Mesoscale Simulation and Evaluation of the Mechanical Properties of Ceramic Seal Coatings

Abstract

Microstructure feature extraction and performance simulations of a Yttria-Stabilized Zir-conia (YSZ) abradable coating applied in the high-pressure turbines of aero-engines, with a service temperature over 1000◦ C were conducted. The finite element method (FEM) numerical models of the abradability, bonding strength, and thermal shock resistance of the YSZ coating were established. The effects of porosity and pore diameter on the properties of the coating were obtained through simulations and calculations. The results indicated that the abradability, bonding strength, and thermal shock resistance of the coating were jointly determined by porosity and pore diameter. With the porosity increasing from 5% to 50%, the bonding strength of the coating decreased gradually, but the abradability and thermal shock resistance of the coating were significantly improved, especially when the porosity was above 20%. With the pore diameter increased from 0.5 µm to 1.5 µm, the abradability, bonding strength, and thermal shock resistance of the coating increased initially, and then decreased. An evaluation function using the normalized weighting strategy was proposed to characterize the comprehensive properties of the coating. The results of the evaluation showed the optimal abradability, bonding strength, and thermal shock resistance of the coating were obtained under a combination of 25% porosity and 1 µm pore diameter. This study may provide guidance for design optimization, and an improvement in the microstructure and properties of coatings in future research.