Development of fine-grained structure and the mechanical properties of nickel-based Superalloy 718

► Grain refinement of Superalloy 718 can be achieved by good combination of solution treatment, cold forming and recrystallization treatment. ► A niobium-oversaturated matrix in addition to sufficient plastic deformation is essential for subsequent recrystallization. ► Formation of uniformly fine dispersed precipitates caused pinning effect for recrystallized grain to grow. ► A fine-grained structure with grain sizes less than 1 μm can be achieved.