Effect of superimposed uniaxial stress on rumpling of platinum-modified nickel aluminide coatings

Thermal cycling of a platinum modified, nickel aluminide (Ni,Pt)Al coated single crystal superalloy, between 1000 and 1150 °C with 10 min holds at each temperature, and subject to a compressive uniaxial stress is reported. There are two major effects of the superimposed compressive stress not observed in the absence of the stress. One is that the rumpling pattern exhibits an asymmetry with an increase of the bond coat surface roughness perpendicular to the applied loading axis. The other is the formation of cracks in the thermally grown oxide aligned parallel to the stress axis.