In-situ study of oxidative damage mechanisms of GH4169 superalloy at 650°C

• PLC effect shown during the stretching of SA alloys at 650 °C. • OA alloys oxidize at 650 °C showing the OAIC effect. • The high-temperature mechanical properties of GH4169 are mainly influenced by grain size, amount of reinforcing phases, PLC and OAIC effects. Under high temperature and high pressure, mechanical property damage of GH4169 due to oxidation is inevitable. In this work, effects of oxidation behavior on the failure process of GH4169 is investigated through high-temperature in-situ tensile experiments. Results show that γ ′ and γ ″ reinforced phases of the alloy disappear and alloy grain size grows after oxidation at 1000°C for 20 h. Meanwhile, the oxidation failure process of the alloy at 650°C is accompanied by Portevin-Le Chatelier (PLC) effect and oxidation-assisted intergranular cracking (OAIC) effect. Under the combined effects of these factors, high-temperature strength of the alloy decreases significantly.