Effect of Hole Geometric Structure on the Oxidation Behavior of DD6 Single-Crystal Superalloy

The isothermal oxidation behavior of DD6 single-crystal superalloy with different hole geometric structure at 1050 ℃ was studied using field emission scanning electron microscope, energy dispersive spectroscope, X-ray diffractometer, and ABAQUS finite element method. The results show that at two angles of 45° and 90°, the average oxidation rate varies with the film-hole spacing, both being 0.75 mm>0.95 mm>0.55 mm>0.39 mm. The effect of film-hole spacing on the oxidation mass gain of single-crystal superalloys is more significant than that of hole angle. At the same film-hole spacing, the degree of oxidation at 45° is relatively more severe than that at 90°. Finite element analysis shows that the growth of the oxide layer on the inner wall of the hole is mainly affected by the temperature field, while the growth of the oxide layer on the surface of the hole is mainly affected by the detachment stress. As the film-hole spacing increases, the stress cancellation area gradually decreases, and the detachment stress continues to increase, reaching its peak at 0.75 mm. At this time, the oxide film detachment is most severe, and after the peak point, it shows a downward trend.