Studying on Rare Earth Aluminizing Process of GH4169 Superalloy
The aluminizing process by solid powder on the surface of GH4169 superalloy with different Y2O3 content and different aluminizing temperature was investigated in this paper. The results show that the crystalline phase of aluminized coating is composed of AlNi, FeNi and AlNi3, and the phase of AlNi reaches 78.1%, which indicates that aluminium atom has infiltrated into the alloy surface. Y2O3 can greatly improve compactness of the aluminized coating, increase thickness, surface micro-hardness and high temperature oxidation resistance of the aluminized coating. The thickness of the coating increases with the increase of temperature, but the microstructure of the aluminized samples cannot obviously divided into aluminized layer, transition layer and matrix when the aluminizing temperature is too high (980°C) or too low (920°C), and even the aluminized coating is porous and coarse at 980°C. The high temperature oxidation resistance of all the aluminized samples is improved compared to without aluminized samples. According to the microstructure, thickness, surface micro-hardness and high temperature oxidation resistance of aluminized coating, the optimal aluminizing process is 950°C×7h with 4%Y2O3.
J. M. Luo et al., "Studying on Rare Earth Aluminizing Process of GH4169 Superalloy", Advanced Materials Research, Vols. 314-316, pp. 267-272, 2011