Microstructural evolution and tensile properties of 70 GPa·% grade strong and ductile hot-rolled 6Mn steel treated by intercritical annealing

The Novel Combination of Strength and Ductility in 0.4C‐7Mn‐3.2Al Medium Manganese Steel by Intercritical Annealing

“…The relationship between the UTS and TE can be expressed by the so‐called banana curves for various AHSS grades. Figure summarizes the UTS and TE data of medium Mn steels in this study and in available literatures with similar Mn content levels . As shown, significantly superior tensile properties could be obtained in this study.…”

“…As shown in Figure b, the WHR is characteristic of the obvious fluctuation in the S 4 stage. Li et al suppose that martensite transformation is the main reason for quick increase and abrupt drop in the d σ /d ε curve. Li et al proposed that excellent strength and plasticity in medium Mn steel might be attributed to the discontinuous TRIP effect involving stress relaxation and transfer during deformation.…”

Microstructure and Mechanical Properties of a Medium-Mn Steel with 1.3 GPa-Strength and 40%-Ductility

“…This could be because the original coarse martensite transformed into austenite during aging, or the original coarse austenite grains were retained during cold rolling, and then coarsened during the long-duration aging treatment. Such austenite grains with a bimodal size distribution, which could transform into martensite or twins during tensile testing, play an important role in determining the steel microstructure evolution and mechanical properties [ 14 ]. In summary, the previous martensite/ferrite banded structure, whose grains can be refined through either recrystallization or transformation into austenite grains during the aging/annealing treatment, plays an inestimable role in the subsequent microstructure evolution.…”

“…The combination of various deformation mechanisms, such as the TRIP effect, TWIP effect, and dislocation strengthening, results in an excellent combination of strength and ductility in medium-Mn steels [ 6 , 14 , 15 ]. The presence of VC and annealing twins ( Figure 6 c) inevitably affects the deformation mechanisms during tensile testing.…”

“…Additionally, it is worth noting that the values of fluctuating peaks in the work hardening rate curves of different aged samples are rather inconsistent. Such a result should be attributed to the great differences in samples, such as in the austenite stability and austenite fraction [6,14]. Additionally, both the austenite fraction and austenite stability are the main factors determining the strain-hardening behavior.…”