Precipitation characteristics of GH4710 alloy and its relationship to plastic damage evolution during hot working process

The characteristics of precipitates and plastic damage in GH4710 alloy, both under original and different hot-forming conditions, were studied based on thermomechanical calculation by the Thermal Calc software and microstructural analysis by optical microscopy and scanning electron microscopy. The relationship between the precipitation characteristic and plastic damage evolution during the hot-forming process was also discussed. It is found that the equilibrium phases of the alloy mainly consist of γ', MC and M₂₃C₆ carbides, and γ/γ' eutectic structure. The MC carbides and eutectic structure act as damage sources during the deforming process, leading to the nucleation and connection of micropores, and then the propagation of macrocracks through the grain boundaries. The γ' phase precipitates preferentially at the MC and eutectic structure region of as-solidified structure, which impedes the nucleation and expanding of micropores by the γ/γ' coherent stress distribution, resulting in a lower plastic damage at sub-solvus deformation temperatures and a higher plastic damage at super-solvus deformation temperatures.