ISSN: 1003-6326
CN: 43-1239/TG

Vol. 26    No. 4    April 2016

Oxidation behavior of RE-modified nickel-based superalloy between 950 °C and 1150 °C in air
Long-fei LIU, Shu-sen WU, Yang CHEN, Shu-lin Lü
(State Key Laboratory of Materials Processing and Die and Mould Technology,
Huazhong University of Science and Technology, Wuhan 430074, China
Abstract: A new Ni-based superalloy Ni48Cr28W5Co3Mn1Si1.6 was developed and the influence of a trace amount of rare earth (RE) metal addition on the oxidation resistance of this alloy was investigated. Isothermal oxidation behavior was investigated at 950-1150 °C in air, and then analyzed using scanning electronic microscopy and X-ray diffraction. The results showed that oxidation mass gain kinetics of the samples with and without RE elements follow the parabolic law. The effect of 0.20% RE on oxidation resistance is relatively small, and the oxidation rate constant of the alloy modified with 0.20% RE addition decreases by 5.9%-9.0%. Oxidation at 950-1150 °C for 100 h results in the formation of MnCr2O4, Cr2O3 and SiO2. A continuous and protective MnCr2O4 spinel layer forms as outer layer. The continuous middle oxide layer is confirmed to be Cr2O3, and the innermost layer consists of discontinuous SiO2.
Key words: Ni-based superalloy; rare earth element; high temperature oxidation; multi-layered oxides
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
Managed by Central South University (CSU)