Investigation of pile-up behavior for thermal barrier coatings under elevated-temperature indentation

The elevated-temperature indentation has been utilized to measure the elevated-temperature mechanical properties of thermal barrier coatings (TBCs), which have a major influence on their thermomechanical characteristics and failures. In this paper, the pile-up phenomenon of TBCs under elevated-temperature indentation was investigated, and a characterization method for Young's modulus of TBCs was proposed. According to the dimensional analysis and finite-element method, a critical temperature-dependent factor was conducted as the criterion for pile-up behavior. Some experiment results agreed fairly well with the criterion. Then, the pile-up behavior of TBCs at elevated temperature was studied. It was found that the pile-up behavior depended on the temperature-dependent factor and got larger with increasing temperature. Finally, a characterization method was proposed to extract the Young's modulus of TBCs, which was found to be more suitable for elevated-temperature indentation.