Influence of precipitates on the initial oxidation behavior of GH4169 superalloy at 1000 °C

• Investigated the growth mechanism of oxide particles at the early stage of oxidation. • Discussed the structure of the oxide layer of GH4169 superalloy. • Investigated the effect of precipitation phases on the oxidation resistance of GH4169 superalloy. The degradation of mechanical properties in superalloys due to high temperature oxidation is unavoidable. In this paper, the initial oxidation (oxidation time less than 3600 s) mechanism of GH4169 superalloy was studied. The results indicate that the superalloy oxide layer consists of three distinct layers. The outer layer is composed of Cr 2 O 3 and Fe 2 O 3 , the middle layer is a mixture of Nb 2 O 5 and MoO 3 , and the inner layer is enriched with Al 2 O 3 and Ti 2 O 3 . Initial oxidation starts preferentially at grain boundaries (GBs). Additionally, the oxide layer of the double aging (DA) alloy is denser. The effects of γ ′ and γ ″ precipitates on the initial oxidation behavior of GH4169 superalloy were studied. The results show that γ ′ and γ ″ precipitates can improve the oxidation resistance of GH4169 superalloy. It provides a research direction for how to improve the oxidation resistance of GH4169 superalloy.