(1. College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China) (2. Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, China) (3. The State Key Laboratory of Nonlinear Mechanics (LNM), Institute of Mechanics, Chinese Academy of Sciences, Beijing 100190, China)
As an advanced coating, micro-/nano-particle ceramic coating is widely used in key components such as aeroengine blades. Its mechanical properties determine the service life and reliability of components to a large extent. The macroscopic mechanical properties of the advanced coatings are closely dependent on their microstructure, that is to say, they have trans-scale mechanical properties. The study of trans-scale mechanical behavior is not only a hot spot, but also of great significance for advanced coating design. In this paper, the microstructure of micro-/nano-particle 8YSZ thermal barrier coating/Ni-based super-alloy system was observed and analyzed firstly. Then, the trans-scale behavior of hardness and elastic modulus was studied by coupling nano-/macro-indentation experiment and trans-scale mechanical theory based on strain gradient and surface/interface effect. It is found that the macroscopic hardness of the surface obeys the Weibull statistical distribution, and the hardness dispersion of the nano-structure coating is small; the hardness of the nanoindentation is high and decreases with the increase of the indentation depth. Moreover, the hardness and modulus decrease with the increase of the distance from the interface.