Microstructure Evolution and Room Temperature Tensile Behavior of GTD222 Superalloy

This paper systematically investigates the evolution of microstructure and tensile properties of the GTD222 superalloy under various heat treatment parameters. The results indicate that the optimal heat treatment for strength-ductility balance is ST-1025°C/1h+AT-802°C/8h, achieving a yield strength (∼900 MPa), an ultimate tensile strength (∼1274 MPa), an elongation (∼34.1%), and a reduction in area (∼45%). Furthermore, an increase in the solution temperature reduces the strength of the alloy while maintaining a consistently ductile fracture mode during room-temperature tensile tests. As the size of the precipitates increases, the dislocation coupling mechanism transitions from weakly coupled to strongly coupled, with the optimal strengthening effect observed at a critical γ′ radius of 13.6 nm where this transition occurs.