The role of texturing and recrystallization during grain boundary engineering of Ni-based superalloy RR1000

The application of grain boundary engineering (GBE) techniques to enhance the physical and mechanical properties of Ni-based superalloys could potentially increase the efficiency of turbine engines. Compared to traditional GBE processes that require multiple iterations of room temperature deformation followed by annealing, novel techniques for GBE based on the optimization of the thermal–mechanical processing parameters exhibit more potential for producing complex-shaped Ni-based superalloys components. To date, the formation and microstructural evolution of Σ3 boundaries during thermal–mechanical processing have yet to be fully understood. In this investigation, the effects of deformation texture and strain were systematically investigated in an advanced Ni-based superalloy, RR1000. Using various strains and annealing temperatures, the effects of recrystallization and texturing were quantified. Although texturing was often associated with recrystallization that caused the length fraction of Σ3 boundaries to decrease, the formation of Goss type texture during deformation was found to promote the formation of Σ3 boundaries upon annealing when compared to deformation texturing 〈111〉 parallel to the rolling direction.