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Evolution Of Surface Morphology Of Thermo-Mechanically Cycled Nicocraly Bond Coats, J. Shi, Anette M. Karlsson, B. Baufeld, M. Bartsch

Mechanical Engineering Faculty Publications

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 …