Liquid oxygen (LOX)/kerosene rocket engines are the main power system of heavy launch vehicles around the globe, and the turbine materials are usually exposed to elevated temperatures, high pressure, and oxygen-enriched environment in gas generators. Metal combustion may occur under these working conditions. GH4061 is a newly developed Ni-based superalloy that is used in turbine materials because of its excellent mechanical properties. However, its combustion resistance property has rarely been studied. Recently, several studies on metal combustion have been conducted, but they mainly focus on exploring the rules of metal combustion. Furthermore, the domestically promoted ignitioncombustion (PIC) experiment equipment only supports the test under 2 MPa pressure, which has significantly limited the study of metal combustion at higher pressure. Therefore, the analysis of the metal combustion mechanism remains incomplete. In this study, the 3.5-25 MPa high pressure and oxygenenriched combustion experiments of GH4061 alloy were performed on the basis of independentlydeveloped PIC equipment with a maximum pressure of 25 MPa. A high-speed camera was used to observe and record the combustion process. The postcombustion microstructure was characterized using SEM and EDS, and the combustion product was identified using XRD. The length and rate of burning increase as the oxygen pressure increases. The critical burning pressure of GH4061 under 99.5% oxygen (when igniting at 25 degrees C) is about 5 MPa, according to ASTM-G124. After testing, the transition zone, melting zone, ignition interface, and oxide zone in the samples were characterized. The burning process is due to elements with a higher heat of combustion. During combustion, lower-density molten oxides float up to the melting zone. After testing, small O/Al/Ti-rich particles and large complex oxide particles with dendritic morphology were observed in the melting zone. The effect of oxygen pressure was analyzed using thermodynamics.
