Effects of trace elements Hf and Si on oxidation behavior of Co-Ni-Al-W-based superalloys at 900°C

Abstract

Purpose This study aims to control the oxidation resistance of Co-based deformed superalloys by adding trace elements Hf and Si. Design/methodology/approach The effects and mechanism of trace elements Hf and Si on the oxidation behavior of Co-Ni-Al-W-based forged superalloys were investigated by cyclic oxidation at 900°C. Findings The results show that the addition of trace elements Hf and Si does not affect the type of surface oxides of Co-Ni-based superalloys, and the oxidation layers of the alloys are TiO2, spinel, Cr2O3, TaTiO4, Al2O3 and TiN from outside to inside. However, the addition of elements can affect the activity of Cr and Ti elements; decrease the formation of TiO2 and TaTiO4 layers, which are harmful to the oxidation performance; and then improve the oxidation resistance of the alloy. Originality/value The relevant research results can not only optimize the microalloying element content of Co-Ni-Al-W-based superalloys, but also provide a new perspective for the composition optimization design of superalloys.