Compositional effects on the high-temperature oxidation lifetime of MCrAlY type coating alloys

摘要

The lifetimes due to chemical failure during high-temperature oxidation of Co and Ni-rich MCrAlY type coating alloys were investigated. They were found to depend critically on the oxidation rate and Al diffusivity in alloy. Re and Al additions increased the life by providing higher 3-phase contents and by lowering the Al diffusivity and oxidation rates. The effects of Re were more pronounced in the Co-rich than the Ni-rich alloys. The observed difference was a result of different alloy phases, with a microstructure of gamma, beta, and sigma in the Co-rich alloys and gamma, beta, and alpha in the Ni-rich alloys. (C) 2015 Elsevier Ltd. All rights reserved.