Materials Science & Engineering A
We investigate morphological surface instabilities on bond coat surfaces of thermal barrier coatings, induced due to thermo-mechanical loading. Experimental results of hollow circular cylindrical specimens, consisting of a directionally solidified superalloy (IN 100 DS) coated with a NiCoCrAlY bond coat, show that the morphological instabilities are strongly dependent on the load conditions. In particular, the morphological instabilities develop during thermal cycling with a thermal gradient over the cylinder wall, whereas the surface remains smooth for thermal cyclic conditions without a gradient. Furthermore, if a cyclic, axial tensile force is applied (synchronized with the thermal cycling), the morphological instabilities become aligned with the axial direction. We discuss a model, quantified by finite element simulations, capturing this behavior and elucidating the thermo-mechanical response.
Shi, J., Karlsson, A. M., Baufeld, B., 2006, "Evolution of Surface Morphology of Thermo-Mechanically Cycled NiCoCrAlY Bond Coats," Materials Science & Engineering A, 434(1-2) pp. 39-52.
NOTICE: this is the author’s version of a work that was accepted for publication in Materials Science & Engineering A. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in Materials Science & Engineering A, 434, 1-2, (10-25-2006); 10.1016/j.msea.2006.07.048