High temperature oxidation resistance of PM superalloys FGH4095 and FGH4096

Abstract

In order to study the oxidation corrosion protection of key components of carrier aero engine, the high temperature oxidation behavior of the Ni-based powder metallurgy(PM) superalloys FGH4095 and FGH4096 in air at the temperature range of 750-1100 ℃ was investigated. The oxidation kinetics curves were determined by static weighing method. The structure, composition, and morphology of the surface oxide scale as well as its cross section were analyzed by metallographic microscope, scanning electron microscope (SEM), electron probe microanalyzer (EPMA) and X-ray diffractometer (XRD). The results show that two kinds of alloys belong to the grade of full oxidation resistance at 750-900 ℃ and oxidation resistance at 1000-1100 ℃. The actual service temperature of both alloys is below 900 ℃, so they exhibit excellent oxidation resistance in their operating temperature range.At 750-900 ℃, the oxidation resistance of the two alloys is similar without obvious difference. The oxide film is intact without peeling.The oxide films of FGH4095 and FGH4096 are composed of two layers after high temperature oxidation. The internal layer is mainly Al2O3.The outer layer of FGH4095 is composed of Cr2O3, Nb2O5 and TiO2. The outer layer of FGH4096 is composed of only Cr2O3 and TiO2.At 1100 ℃, both alloys are obviously oxidized and a large number of oxide scales crack. Due to the different compositions of the alloys, the oxidation resistance of the two alloys varies greatly at this temperature.In contrast, FGH4095 alloy exhibits better oxidation resistance.

Keywords

• fgh4095
• fgh4096
• pm superalloy
• high temperature oxidation
• oxidation rate
• oxide layer