Novel ferrite–austenite duplex lightweight steel with 77% ductility by transformation induced plasticity and twinning induced plasticity mechanisms

Sohn, Seok Su; Choi, Kwonhue; Kwak, Jai Hyun; Kim, Nack J.; Lee, Sunghak

doi:10.1016/j.actamat.2014.06.059

Cited by 146 publications

(70 citation statements)

References 38 publications

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“…8). These results indicate that deformation mechanisms are varied with C and Al contents, grain sizes, and partitioning effects of C and Mn in austenite according to the existence of ferrite, although of the present annealed steels are kinds of medium-Mn steels generally showing TRIP or TWIP mechanisms [10][11][12]39].…”

Section: Discussionmentioning

confidence: 75%

“…10 shows room-temperature tensile properties of the steels, and their chemical compositions, annealing conditions, and constituent phases are summarized in Table 3. The medium-Al lightweight steels containing similar Al content to that of the present steels show relatively low austenite stabilizing effects of C and Mn because of the high content of Al, a powerful ferrite former [11,12,37,39]. Since the stable austenite can be hardly obtained at room temperature, secondary phases such as j-carbides in the ferrite matrix should be used for strengthening.…”

Section: Discussionmentioning

confidence: 86%

“…Comparison of room-temperature tensile properties of the present Fe-0.7C-12Mn-5.5Al ultra-high-strength lightweight steels with recently developed high-strength Fe-Mn-Al-C-based steels[6,11,12,15,19,37,39,49].…”

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confidence: 99%

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Novel ultra-high-strength (ferrite + austenite) duplex lightweight steels achieved by fine dislocation substructures (Taylor lattices), grain refinement, and partial recrystallization

et al. 2015

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Section: Discussionmentioning

confidence: 75%

Section: Discussionmentioning

confidence: 86%

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Novel ultra-high-strength (ferrite + austenite) duplex lightweight steels achieved by fine dislocation substructures (Taylor lattices), grain refinement, and partial recrystallization

et al. 2015

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“…[25] For instance, the formation of martensite in metastable austenitic steels [38] results in an increase in the strain-hardening rate. On the other hand, the planarity of dislocations glide during tensile straining of TWIP steels is associated with near-linear strain hardening.…”

Section: A Microstructure Before Deformationmentioning

confidence: 99%

“…One possible way is the Al addition. [21][22][23][24][25][26] Al-alloyed duplex steels developed for this purpose have been modifications of the Fe-Mn-C alloy system. [27] In spite of the ever-increasing interest in the use of DSSs, Al addition to Fe-Cr-Mn-Ni class of stainless steels has not received as much attention as Al addition to Fe-Mn-C alloys.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Evolution of an Al-Alloyed Duplex Stainless Steel During Tensile Deformation Between 77 K and 473 K (−196 °C and 200 °C)

Rahimi

Ullrich

Rafaja

et al. 2016

Metall Mater Trans A

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Tensile deformation behavior of an Al-alloyed Fe-17Cr-6Mn-4Al-3Ni-0.45C (mass pct) duplex stainless steel containing approximately 20 vol pct ferrite was studied in the temperature range from 77 K to 473 K (À196°C to 200°C). While the elongation exhibited a maximum near room temperature, the yield strength continuously increased at lower tensile test temperatures. According to the microstructural examinations, the twinning-induced plasticity and the dislocation cell formation were the dominant deformation mechanisms in the austenite and ferrite, respectively. Reduction of the tensile ductility at T < 273 K (0°C) was attributed to the ready material decohesion at the ferrite/austenite boundaries. Tensile testing at 473 K (200°C) was associated with the serrated flow which was ascribed to the Portevin-Le Chatelier effect. Due to a rise in the stacking fault energy of austenite, the occurrence of mechanical twinning was impeded at higher tensile test temperatures. Furthermore, the evolution of microstructural constituents at room temperature was studied by interrupted tensile tests. The deformation in the austenite phase started with the formation of Taylor lattices followed by mechanical twinning at higher strains/stresses. In the ferrite phase, on the other hand, the formation of dislocation cells, cell refinement, and microbands formation occurred in sequence during deformation. Microhardness evolution of ferrite and austenite in the interrupted tensile test specimens implied a higher strain-hardening rate for the austenite as it clearly became the harder phase at higher tensile strain levels.

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Tailoring Strength and Ductility of an Fe–Mn–Al–C Low‐Density Duplex Steel by Controlling the Cooling Path after Hot Rolling

Li,

Chen,

Wang

et al. 2023

Adv Eng Mater

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The low‐density duplex steels provide a potential for the industrial application owing to their good strength‐ductility match and reduced density. In the present work, the microstructure of an Fe–8.03Mn–6.10Al–0.4C (wt%) low‐density duplex steel was adjusted by controlling the cooling path after hot rolling, which is a conventional process during the production of steel sheets and strips. A microstructure of ferrite and austenite has been achieved by annealing the air‐cooled samples, and the microstructure of furnace‐cooled annealed samples consists of banded ferrite, austenite, and martensite. This is mainly due to the fact that the austenite is more stable by refining the grain size via embedding the needle‐like α‐ferrite. The existing of martensite and the banded microstructure in furnace‐cooled annealed samples induces the occurrence of cracks during deformation, resulting in an abrupt fracture at a relatively lower strain level. However, for air‐cooled annealed samples, a good ductility of duplex microstructure ensures that the deformation can be sustained up to a much higher strain level, and the transformation induced plasticity effect plays a positive role at the later deformation stage; this contributes to the occurrence of an extra work hardening rate recovery during deformation and thus to a good strength‐ductility match.

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Novel ferrite–austenite duplex lightweight steel with 77% ductility by transformation induced plasticity and twinning induced plasticity mechanisms

Cited by 146 publications

References 38 publications

Novel ultra-high-strength (ferrite + austenite) duplex lightweight steels achieved by fine dislocation substructures (Taylor lattices), grain refinement, and partial recrystallization

Novel ultra-high-strength (ferrite + austenite) duplex lightweight steels achieved by fine dislocation substructures (Taylor lattices), grain refinement, and partial recrystallization

Microstructural Evolution of an Al-Alloyed Duplex Stainless Steel During Tensile Deformation Between 77 K and 473 K (−196 °C and 200 °C)

Tailoring Strength and Ductility of an Fe–Mn–Al–C Low‐Density Duplex Steel by Controlling the Cooling Path after Hot Rolling

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