Effects of Cold Deformation and Heat Treatment on the Structure and Properties of GH4169

In this study, the microstructure and mechanical properties of GH4169 alloy subjected to cold deformation and aging were investigated. The results indicate that the tensile strength and yield strength of GH4169 alloy increase after cold deformation and further elevate after aging. The ultimate tensile strength reaches 1598 MPa, and the yield strength reaches 1396 Mpa. This is primarily attributed to the continuous multiplication of dislocations after cold deformation, with the emergence of numerous dislocation pile-ups and entangled dislocations leading to an increasing resistance to dislocation movement, thereby enhancing the alloy’s strength. After aging, a significant amount of spherical γ′ and lamellar γ″ phases precipitate at grain boundaries and within grains, hindering dislocation movement and providing secondary phase strengthening, further increasing the strength. Additionally, the fracture mode of the alloy transitions from transgranular fracture before aging to intergranular fracture after aging. This transition is attributed to the pinning effect of the precipitated δ phase at grain boundaries.