Microstructure-mechanical property evaluation and deformation mechanism in Al added medium Mn steel processed through intercritical rolling and annealing

Deformation‐induced mechanisms, namely, transformation‐induced plasticity (TRIP) and twinning‐induced plasticity (TWIP), are primarily responsible for improved tensile properties in medium‐Mn steels. Additionally, lower density and processing costs make these steels useful in various industries, particularly the automotive industry, which mandates a good understanding of underlying processing–microstructure–property correlations. Therefore, the present study reviews different thermomechanical processes and corresponding microstructural evolutions, followed by mechanical properties. In addition, an assessment of the fatigue behavior of medium‐Mn steels based on duplex or multiphase microstructure and associated mechanisms has been presented. In high‐cycle fatigue (HCF) loading, strain‐induced martensite formation through TRIP at the crack tip is a barrier to dislocation motion. It deviates the crack propagation path to adjacent phases, which results in higher fatigue life. On the other hand, relatively high martensite boundaries initiate microcracks and accelerate crack propagation, resulting in lower life in low‐cycle fatigue (LCF). However, the TWIP mechanism prevents cyclic softening and promotes cyclic saturation, extending fatigue life. The compositions of medium‐Mn steel for enhanced fatigue resistance have been proposed. To that end, it is hypothesized that the TRIP + TWIP mechanisms lead to exceptional LCF performance. Further, microalloyed medium‐Mn steels are expected to exhibit improved LCF and HCF behavior.

“…These techniques cause the formation of multiple phases with various morphologies. Nevertheless, processing parameters such Fe-0.25C-8Mn-4Al-0.6Si [6] Austenitization followed by…”

Section: Processing and Microstructure Evolutionmentioning

confidence: 99%

Section: Processing and Microstructure Evolutionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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A Systematic Review of Medium‐Mn Steels with an Assessment of Fatigue Behavior

Kumar,

Sen,

Bandyopadhyay

2023

“…Several endeavors have been conducted for improving the volume fraction of austenite with a suitable stability by optimizing the IA parameters. [9][10][11][12][13] Temperature rise could occur during the manufacturing and service application of MMS, for example, the painting processes are adopted to improve the corrosion resistance of automobile structural components. The baking temperature after painting is generally as high as %170-200 °C.…”

Section: Introductionmentioning

confidence: 99%

“…Several endeavors have been conducted for improving the volume fraction of austenite with a suitable stability by optimizing the IA parameters. [ 9–13 ]…”

Section: Introductionmentioning

confidence: 99%

Potential Significance of Low Tempering Treatment in Improving the Mechanical Properties of a Cold‐Rolled and Intercritical Annealed Medium Mn Steel

Zhang

Duan

Liu

et al. 2022

Herein, the effect of tempering at 200 °C for 20 min on the mechanical properties of a cold-rolled and intercritical annealed medium Mn steel is investigated in this study. This effect is mainly dependent on the original annealing condition. For the sample annealed at a relatively low temperature (660 °C), the austenite stability of this sample is further improved significantly after tempering. Thus, the transformation-induced plasticity (TRIP) effect is severely inhibited during deformation, which leads to a decrease in the properties of the sample. By contrast, for the sample possessing suitable austenite fraction (%30%) and heterostructure, that is, the sample annealed at 680 °C for 10 min, the simultaneously increased strength and ductility are significantly intrigued by tempering treatment. Electron probe microanalysis and 3D atom probe results reveal that C concentration in austenite is increased due to the C repartition during tempering, which leads to the persistent TRIP effect in a broad strain range during tensile deformation. In addition, the heterogeneous-deformation-induced stress of the heterostructured sample is found to be obviously intensified by tempering treatment. Thus, an excellent strength plastic synergistic effect with a product of ultimate tensile strength and total elongation of approximately 70 GPa% is obtained in the tempered sample.

Effect of Austenite Reversion and Its Stability on the Tensile and Impact Transition Behavior of High‐Strength Naval Steel

Biswal,

Sk,

Barik

et al. 2023

The present investigation correlates the austenite reversion and its stability during intercritical annealing (IA) with the tensile and Charpy impact properties of a low‐C naval grade steel. The as‐received steel is subjected to water quenching after austenitization at 950 °C, followed by IA at 620, 650, and 680 °C for 2 h. DICTRA simulation is used to predict the austenite reversion kinetics during the IA. Incorporation of cementite phase in the simulation correlates well with the experimental dilatometry results on the austenite growth kinetics. DICTRA simulation predicts a continuous rise in the reverted austenite fraction with increasing IA temperature. However, the percentage of reverted austenite, that gets retained after the subsequent quenching, decreases with increasing annealing temperature due to the reduction of austenite stability at elevated IA temperature. In other words, the amount of fresh untempered martensite increases rapidly with increasing IA temperature. Consequently, the sample annealed at an intermediate temperature of 650 °C (IA650) shows the best combination of strength, elongation, and low‐temperature impact properties as compared to the IA620 and IA680 steels due to an optimum balance of mechanically stable austenite and relatively lower untempered martensite fractions.