Abstract
A fundamental study of inelastic deformation of freestanding plasma-sprayed thermal barrier coatings (TBCs) has been conducted. Cantilever-type bending tests are carried out to obtain stress-strain curves from freestanding ceramic layers detached from the TBC-coated sample via electrochemical treatment. In order to investigate inelastic deformation in the sample, in-situ scanning electron microscope (SEM) observation is performed by means of a small tensile testing device that can be inserted into the SEM vacuum chamber. The bending test result indicated that the coating deforms with a nonlinear behavior under monotonic loading, in spite of the fact that it is a ceramic material. Spray parameters such as in-flight velocity affected the stress-strain curve significantly. In-situ SEM observation during the bending test revealed that sliding at boundaries between splats plays an important role in inelastic deformation.
