Primary Carbide Refinement in AISI M50 Steel by Dislocation Engineering Via Pre-deformation Treatment

A novel mechanism was proposed to accelerate the refinement of metastable M 2 C in M50 steel by implementing a well-designed pre-deformation treatment. Compared with the samples treated by traditional diffusion, the new mechanism decreased the M 2 C area percentage by nearly 30 pct. Deformation dislocations caused the transition mechanism of M 2 C to transform into a coexisting interfacial and internal nucleation mode. The nucleation sites and alloying element rapid diffusion channels were increased through deformation, which accelerated the transformation and diffusion dissolution of M 2 C. The significant refinement of the primary carbide led to longer fatigue life and greater reliability under fatigue loading.