MC precipitates affected by nitrogen addition in Ti-V-Nb micro-alloyed high manganese steel

Abstract

Precipitation, as a practical strengthening method, can enhance the mechanical properties of Ti-V-Nb alloyed high manganese (HM) steel. However, the presence of initial large-size precipitates, specifically large-size eutectic carbides formed during solidification, cannot be effectively eliminated through subsequent heat treatments, resulting in compromised plasticity and toughness. In this study, the addition of N was found to influence the precipitation of M(Ti-V-Nb)C, leading to a refinement in the size of precipitates and an increase in their volume fractions, while their morphology and crystal structure remained largely unchanged. This improvement reduces the detrimental effects of large-size precipitates on steel properties, resulting in enhanced incremental precipitation strengthening and improved tensile strength, yield strength, elongation, and hardness of nitrogenous high manganese steel (NHM) compared to HM. This research provides valuable insights into controlling precipitation and enhancing the mechanical properties of Ti-V-Nb alloyed high manganese steel through nitrogen introduction.