• Mn doping improves hardness, stiffness, and alleviates corrosion susceptibility. • Pre-straining induces the TRIP effect, enhancing strength but reducing ductility. • TRIP-induced martensite triggers micro-galvanic cells, promoting pitting corrosion. • Pre-straining raises corrosion current density and decreases polarization resistance. • The TRIP effect improves steel strength but elevates localized corrosion risk. This study explores modulation of TRIP effects on localized corrosion behavior of medium-manganese steel, through a combination of computational simulations and multi-scale characterization methods. Results demonstrate Mn doping enhances stiffness and toughness in both BCC-Fe and FCC-Fe phases while reducing surface energy, thereby lowering corrosion susceptibility. Pre-straining triggers the TRIP effects through phase transformation of metastable retained austenite to deformation-induced martensite, which enhances yield strength and hardness while increasing dislocation density and stress concentration. Hence, micro-galvanic cells are formed between deformation-induced martensite and ferrite/retained austenite phases, which promotes pitting corrosion. Additionally, pre-straining elevates corrosion current density while decreasing polarization resistance, confirming the degradation of corrosion resistance. While the TRIP effects enhance mechanical performance, it increases localized corrosion risks due to microstructural heterogeneity, stress concentration and corrosion product film instability. These findings emphasize the need to balance mechanical properties and corrosion resistance in medium-manganese steels for marine engineering applications.
Cheng et al. (Wed,) studied this question.