Improved ductility of a transformation-induced-plasticity steel by nanoscale austenite lamellae

Shen, Y.F.; Liu, Yandong; X, Sun; Wang, Y. D.; Zuo, Liang; Misra, R.D.K.

doi:10.1016/j.msea.2013.06.062

Cited by 46 publications

(27 citation statements)

References 31 publications

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“…Most of the existing investigations on TRIP steels mainly focus on improving the mechanical properties by adjusting the volume fraction ratio of ferrite to austenite, which can be achieved by controlling chemical compositions and/or heat treatment processes [15,16,17,18]. Only a handful of works have noted that excellent mechanical properties of TRIP steels can be obtained by controlling the morphology of austenite [19,20]. In the current work, we demonstrate that excellent combination of strength and ductility of a medium Mn TRIP steel can be achieved by controlling the volume fraction and the morphology of austenite through hot rolling followed with warm rolling (without the annealing process), replacing the traditional three-stage processes including hot rolling, cold rolling, and annealing.…”

Section: Introductionmentioning

confidence: 99%

Effects of Intercritical Annealing Temperature on Mechanical Properties of Fe-7.9Mn-0.14Si-0.05Al-0.07C Steel

et al. 2014

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A medium Mn steel has been designed to achieve an excellent combination of strength and ductility based on the TRIP (Transformation Induced Plasticity) concept for automotive applications. Following six passes of hot rolling at 850 °C, the Fe-7.9Mn-0.14Si-0.05Al-0.07C (wt.%) steel was warm-rolled at 630 °C for seven passes and subsequently air cooled to room temperature. The sample was subsequently intercritically annealed at various temperatures for 30 min to promote the reverse transformation of martensite into austenite. The obtained results show that the highest volume fraction of austenite is 39% for the sample annealed at 600 °C. This specimen exhibits a yield stress of 910 MPa and a high ultimate tensile stress of 1600 MPa, with an elongation-to-failure of 0.29 at a strain rate of 1 × 10−3/s. The enhanced work-hardening ability of the investigated steel is closely related to martensitic transformation and the interaction of dislocations. Especially, the alternate arrangement of acicular ferrite (soft phase) and ultrafine austenite lamellae (50–200 nm, strong and ductile phase) is the key factor contributing to the excellent combination of strength and ductility. On the other hand, the as-warm-rolled sample also exhibits the excellent combination of strength and ductility, with elongation-to-failure much higher than those annealed at temperatures above 630 °C.

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Section: Introductionmentioning

confidence: 99%

Effects of Intercritical Annealing Temperature on Mechanical Properties of Fe-7.9Mn-0.14Si-0.05Al-0.07C Steel

et al. 2014

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“…The heating and austenitization treatments were carried out in vacuum (5 Â 10 À 8 MPa), and cooling process was achieved using argon gas. The specimens were heated to 1200°C at a heating rate of 10°C/s for 60 s. A preliminary dilatometry study indicated that the austenite-starting temperature (A c1 ) and austenite-finishing temperature (A c3 ) are 712°C and 892°C, with an error of 72°C [10]. The bainite-start temperature (B s ) and bainite-finish (B f ) temperature were 450°C and 380°C and the martensite-start temperature (M s , 370°C) at a cooling rate of 40°C/s [11].…”

Section: Heat Treatmentmentioning

confidence: 99%

“…Samples were scanned at a step size of 0.02°/s in the 2θ range of 40-80°. The volume fraction of retained austenite phase (V γ ) was determined using integrated intensity of (111) γ , (200) γ and (220) γ , and ferrite peaks (110) α and (200) α [10][11][12]. The carbon concentration x c of austenite was obtained by assuming that the lattice parameter is related to the grain's chemical composition [13]:…”

Section: Microstructural Characterizationmentioning

confidence: 99%

Activated dynamic strain aging of a TRIP590 Steel at 300 °C and low strain rate and relationship to structure

Shen¹,

Wang²,

Liu³

et al. 2015

Materials Science and Engineering: A

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“…Retained austenite (RA) in martensitic steels has been studied extensively because of its complex effects on the service of components [1][2][3][4][5][6][7]. The presence of RA in martensitic steels could cause shape distortion and size instability of components owing to further transformation caused by external stress.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and mechanical properties of a low-carbon HDQ&P steel

Yang

et al. 2019

Heat Treatment and Surface Engineering

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The microstructure and mechanical properties of Fe-0.19C-1.46Mn-1.50Si, a low-carbon hotrolling direct quenching and partitioning steel, were investigated, and particular emphasis was placed on the effects of the rolling temperature and the subsequent cooling method. Once rolling occurred above the recrystallization temperature, the grain size of prior austenite could be reduced from ∼88.2 to ∼11.8 μm. The corresponding packet and block sizes of martensite could be reduced from ∼17.6 to ∼4.3 μm and from ∼9.0 to ∼1.8 μm, respectively, after a typical two-step quenching and partitioning (Q&P) treatment following rolling immediately. Once rolling occurred below the recrystallization temperature, deformed prior austenite with a grain length and width of ∼150 and ∼60 μm, respectively, were obtained. Consequently, only the block size would be reduced to ∼1.9 μm. The volume fraction of retained austenite (RA), which was ∼11% in the specimens, was not significantly affected by the rolling temperature. Further, if the typical two-step Q&P treatment was replaced by air cooling after the rolled specimen was quenched to the martensitic start temperature, the volume fraction of RA in the specimen was reduced to ∼7.4%, and the corresponding carbon depletion degree in the martensitic matrix was decreased as well. Tension and impact tests indicated that the cooling method was more critical than the rolling temperature for determining the mechanical properties. The presence of sufficient amounts of RA and carbon depletion in the refined martensitic matrix contribute to the strong strain hardening and energy absorption capabilities of the steel together. As a result, rolling at a temperature that was slightly higher than the recrystallization temperature combined with the typical two-step Q&P treatment could be an optimized process to obtain excellent comprehensive mechanical properties. In particular, the ductile-to-brittle transition temperature (DBTT) could be reduced from −10°C to −30°C.

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Improved ductility of a transformation-induced-plasticity steel by nanoscale austenite lamellae

Cited by 46 publications

References 31 publications

Effects of Intercritical Annealing Temperature on Mechanical Properties of Fe-7.9Mn-0.14Si-0.05Al-0.07C Steel

Effects of Intercritical Annealing Temperature on Mechanical Properties of Fe-7.9Mn-0.14Si-0.05Al-0.07C Steel

Activated dynamic strain aging of a TRIP590 Steel at 300 °C and low strain rate and relationship to structure

Microstructure and mechanical properties of a low-carbon HDQ&P steel

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