High-temperature oxidation behaviour of a Co-based superalloy fabricated through laser powder bed fusion
Chuan Guo, Yu Li, Ying Li, Gan Li, Xinya Lu, Zhuoyu Li, Xuliang Chen, Xinggang Li, Lin Zhou, Qiang Zhu, Jian Lü
Abstract
This study investigated the oxidation behaviour of a Co-based superalloy fabricated through laser powder bed fusion at 900 ℃. In terms of oxidation products, the results revealed the generation of basic oxides , such as CoO, Al 2 O 3 and TiO 2 , and Co-containing spinels, such as CoAl 2 O 4 and Co 2 TiO 4 . Heat treatment improved oxidation resistance by reducing the parabolic oxidation rate constant from 0.17234 to 0.10032 mg 2 cm −4 h −1 . γ′ precipitates, twin boundaries and less spallation in the heat-treated sample contributed to this improvement, leading to a superior oxidation resistance in this study than in previously reported Co-Al-W-based alloys.