Effect of Y₂O₃ Content on High Temperature Oxidation Resistance of Ni-20Cr-5Al Alloy

The 0-5wt% Y2O3 powders were added to the mixed powders of nickel, chromium and aluminum at a certain ratio as a dispersion phase, and then the Ni-20Cr-5Al-xY2O3 (mass/%) oxide dispersion strengthened Ni-based superalloys were prepared by the powder metallurgy technology. The isothermal oxidation tests of the alloys were carried out at 1 150 ℃ for 100 h and the effects of Y2O3 content on the high temperature oxidation resistance of the alloys were studied. The results show that the experimental alloys all had an excellent oxidation resistance after oxidation for a long time with the Y2O3 content of 0-5wt%.The addition of Y2O3 can promote the formation of Cr2O3 in the surface oxidation films of the experimental alloys, but also reduced the density and adhesion of the oxide films with the addition of 1wt%-5wt%, resulting in the decrease of the high temperature oxidation resistance of the alloys.