航空发动机与燃气轮机是关乎国防安全、能源安全与工业竞争力的战略高技术装备，热障涂层是事关其服役安全和寿命的关键核心技术之一。近年来，随着先进航空发动机与燃气轮机技术的发展，燃烧室、涡轮叶片等热端部件的服役温度不断提高，对热障涂层的隔热性能和服役寿命提出了越来越高的要求，传统等离子喷涂热障涂层已无法满足。在热障涂层中引入一定密度的周期分布表面裂纹，可以同时提升涂层的隔热性能和服役寿命，是一种极具经济性和可行性的先进热障涂层技术。然而，目前这种涂层中表面裂纹形成的力学机制研究尚不充分。本文以等离子喷涂热障涂层表面裂纹的形成过程为对象，发展了考虑热应力的多层结构剪切滞后模型，推导了表面裂纹形成前陶瓷层内应力场与位移场的解析解，获得了不同预热温度下陶瓷层内平均应力、平均应变能密度及总应变能随涂层厚度的演变规律，阐明了预热温度对表面裂纹形成的影响，为实现高热障和高应变容限热障涂层的可控制备提供了理论指导。
Aircraft engine and gas engine are the major strategic equipments related to the national energy security, defense security and industrial competitiveness, and thermal barrier coating system (TBCs) on hot components is one of the key technologies related to its safety and life. In recent years, with the development of advanced aircraft engine and gas turbine technologies, the work temperature of hot components such as combustion chamber and blades is increasing, putting forward higher and higher requirements for the thermal insulation and service life of TBCs, which can’t be satisfied by the tradition air plasma sprayed (APS) coatings. It is a new TBCs technology with great economy and feasibility by introduction periodic surface cracks with certain density into ceramic coating to improve both the thermal insulation and service life of TBCs. However, the formation mechanism of surface cracks in ceramic layer is still unrevealed. In this work, a shear-lag model considering thermal stresses in multilayer structure is developed, and the analytical solutions of the stress and displacement fields in ceramic layer before the formation of surface cracks are derived. The evolution of average stress, average strain energy density and total strain energy in plasma sprayed ceramic layer with coating thickness under different preheating temperatures are obtained. The results illustrate the effect of preheating temperature on the formation of surface cracks in TBCs, which providing theoretical guidance for the controllable preparation of advanced TBCs.
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