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ACTA AERONAUTICAET ASTRONAUTICA SINICA ›› 2022, Vol. 43 ›› Issue (6): 526184-526184.doi: 10.7527/S1000-6893.2021.26184

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Effect of preheating temperature on formation of surface cracks in thermal barrier coating system

LI Dingjun1,2, YANG Liuyu1, SUN Fan1, JIANG Peng1, CHEN Yiwen2, WANG Tiejun1   

  1. 1. State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace Engineering, Xi'an Jiaotong University, Xi'an 710049, China;
    2. State Key Laboratory of Long-Life High Temperature Materials, Dongfang Turbine Co., Ltd. of Dongfang Electric Corporation, Deyang 618000, China
  • Received:2021-08-02 Revised:2022-06-22 Online:2022-06-15 Published:2022-07-07
  • Supported by:
    National Science and Technology Major Project(2019-VII-0007-0147)

Abstract: Current development in advanced aero-engine and gas turbine technologies has increased the work temperature of hot components, constantly imposing higher requirements for the thermal insulation and service life of Thermal Barrier Coating system (TBCs). The introduction of periodic surface cracks with certain density into the ceramic coating to improve both thermal insulation and service life of TBCs is a new TBCs technology. However, the formation mechanism of surface cracks in the ceramic layer is still unclear. This study develops a shear-lag model considering thermal stresses in multilayer structures, and derives the analytical solutions of the stress and displacement fields in the ceramic layer before the formation of surface cracks. The evolution law of average stress, average strain energy density, and total strain energy in the plasma sprayed ceramic layer with coating thickness at different preheating temperatures is obtained. It's observed that the average stress and average strain energy density of coating layer remain the same before surface crack formation in deposition, while total strain energy keeps growing with the coating thickness, which means total strain energy is the key parameter associated with surface crack formation. Besides, it's easy to conclude that the higher preheating temperature is, the more easier surface crack formation is when the other deposition parameters are settled. The results illustrate the effect of preheating temperature on the formation of surface cracks in TBCs, providing theoretical guidance for the controllable preparation of advanced TBCs.

Key words: aero-engines, gas turbines, thermal barrier coating system for hot components, surface cracks, shear-lag model, preheating temperature, strain energy

CLC Number: