The N08120 nickel-based superalloy is a high-performance material with extensive application potential in aerospace, petrochemistry, photovoltaic energy, and other fields, owing to its exceptional high-temperature mechanical properties and corrosion resistance. However, the evolution of microstructure and properties in the Ni-Cr-Fe-based N08120 alloy during hot rolling requires further investigation. Particularly, the recrystallization behavior, texture evolution, and strengthening mechanisms under high temperatures and varying deformation amounts remain obscure.
In this research, rolling experiments were conducted at 780 ℃ with different deformation amounts (40%–80%) to examine the evolution of grain morphology, precipitate behavior, texture transformation, and dislocation structures in the N08120 alloy during hot deformation, along with the corresponding changes in the mechanical properties.
The main conclusions are as follows:
1) With increasing deformation, the initial precipitates undergo progressive fragmentation and refinement. After 40% deformation, finely dispersed carbides are precipitated at the grain boundaries and within the grain interiors. These carbides subsequently experience coarsening during further deformation, effectively impeding the dislocation motion and thereby enhancing the material strength.
2) The crystallographic texture evolves from Rotated Goss {110}<110> to Rotated Cube {110}<112>, eventually stabilizing as the Copper {112}<111> texture.
3) Below 40% deformation, rapid dislocation multiplication results in significant work hardening. Beyond this threshold, the dislocation density growth rate is moderated considerably, where dynamic recovery emerges as the dominant softening mechanism, while the dynamic recrystallization remains confined to regions adjacent to original grain boundaries.
4) After 40% deformation, the material exhibits a substantial enhancement in yield strength and microhardness, though with a corresponding reduction in elongation. Further deformation beyond this level leads to stabilized mechanical properties. Overall, the condition of 40% deformation achieves a favorable strength-ductility synergy.