Determination of mechanical properties of electron beam-physical vapor deposition-thermal barrier coatings (EB-PVD-TBCs) by means of nanoindentation and impact testing

Abstract EB-PVD-zirconia coatings are well known as thermal barrier coating materials for gas turbine applications. Using these materials, the gas turbine can work at higher temperatures, and thus the turbine efficiency increases. Due to the fact that not only the turbine efficiency, but also its reliability is a very important issue, prediction of the lifetime of thermal barrier coatings by assessment through simulation and modeling becomes very important. Developing a model of an anisotropic EB-PVD coating requires knowledge of the mechanical behavior of the coating material. In the present paper, the mechanical properties of the coatings investigated were determined by means of advanced experimental analytical procedures. Stress–strain curves for the coatings examined were determined by a continuous, finite element method (FEM)-supported simulation of indenter penetration into the coating surface. Moreover, the superficial EB-PVD ZrO 2 coating was examined by means of an impact tester to determine its time-dependant plasticity (apparent creep) under dynamic load. The critical stresses for apparent creep of the coating are defined by means of an FEM-supported algorithm presented in previous publications.