Temperature Dependence of Oxidation Properties for 5^th Generation Ni-Base Single-Crystal Superalloys

Abstract

  The oxidation properties of the 5^th generation Ni-base Superalloys, TMS-173 and TMS-196 were investigated comparing with 2^nd generation superalloy, PWA-1484. Isothermal oxidation examination was performed at the temperatures from 1023 K to 1373 K in air for up to 3.6×10⁶ s, and the oxides formed on the specimen surface during oxidation tests were identified by using XRD analysis and SEM cross section observation.
  TMS-173 formed thick NiO layer on the surface caused by the outward diffusion of Ni at 1023 K and showed poor oxidation resistance at 1173 K and 1373 K due to the spinel formation. TMS-196 and the 2^nd generation superalloy PWA-1484 show protective Al₂O₃ layer formation and excellent oxidation resistance at all temperatures examined in this study. This favorable result was caused by their high Cr content.