Desirable Eutectoid Carbides for Ductility Enhancement of Annealed High-Speed Steel

Limited cold formability has been a longstanding challenge for processing high-speed steels. In this study, we probe the relationship between the ductility and eutectoid carbides. The results show that larger-fractioned eutectoid carbides are formed and gradually evolve from granular M6C to rod-shaped M23C6 with increasing annealing duration. Rod-shaped M23C6 carbides have limited shear resistance and are readily sheared by dislocations at large strains, which deteriorates work-hardening abilities and the ductility. Highly dispersive M6C eutectoid carbides are desirable for the ductility enhancement of annealed high-speed steels.