Effect of pre-existed austenite on austenite reversion and mechanical behavior of an Fe-0.2C-8Mn-2Al medium Mn steel

Ding, Ran; Dai, Zongbiao; Huang, Mingxin; Yang, Zhigang; Zhang, Chi; Chen, Hao

doi:10.1016/j.actamat.2018.01.009

Cited by 165 publications

(79 citation statements)

References 51 publications

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“…Finally, we compare our results on the transformation asymmetry with experiments. Experimentally, austenite reversion from martensite can be obtained by annealing [2,46,47], which makes austenite thermodynamically more favourable than martensite. This drives the reverse transformation.…”

Section: Discussionmentioning

confidence: 99%

Contribution of austenite-martensite transformation to deformability of advanced high strength steels: From atomistic mechanisms to microstructural response

et al. 2018

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Steels combining austenite (fcc) with lath martensite (bcc) in nanolaminate microstructures are tough, resistant to hydrogen-embrittlement, and inexpensive, making them attractive for many technological applications. Austenite provides plastic deformation while martensite provides strength, but the nanoscale processes that control plasticity in the austenite layers are not fully established. Recent atomistic simulations and crystallographic theory reveal a unified understanding of the structure and motion of the fcc austenite-bcc (lath) martensite interface in steels, with transformation strains up to ∼ 90% in Fe-C alloys. In this paper, the atomistic behavior is connected to the ductility of nanolaminate microstructures. First, the mechanical response of the atomistic fcc/bcc interface under shear loading is analyzed. The interface motion follows a Schmid-type law for resolved shear stresses in the transformation direction. Furthermore, the forward fcc-to-bcc transformation is spontaneous while the reverse bcc-to-fcc transformation requires high stress. The asymmetry correlates well with the Peierls stresses for fcc and bcc screw dislocations, respectively. Second, the atomistic results guide the formulation of a two-scale continuum model for the phase transformation. The multi-scale strategy adopted here accounts for the relevant nano-scale mechanisms and enables modeling the mechanical response of real martensite microstructures, up to the scale of tens of micrometers-which would be untractable with direct atomistic simulations. Multi-scale simulations show that forward transformation contributes significantly to the apparent plasticity in lath martensite. This reinforces recent work highlighting the importance of such nanoscale austenite films for achiev-*

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Section: Discussionmentioning

confidence: 99%

Contribution of austenite-martensite transformation to deformability of advanced high strength steels: From atomistic mechanisms to microstructural response

et al. 2018

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“…This steel exhibits excellent strength-ductility balance derived from the TRIP effect due to retained austenite in which Mn and C are concentrated during intercritical annealing (IA). [1][2][3][4][5][6][7][8][9] To obtain excellent mechanical properties of medium Mn steel by ensuring that the TRIP effect is continued to the high-strain region, it is essential to increase the volume fraction of retained austenite, as well as improve its stability against deformation. To achieve this, a sufficient degree of partitioning of Mn from ferrite to reversed austenite is necessary.…”

Section: Introductionmentioning

confidence: 99%

Control of Core-shell Type Second Phase Formed via Interrupted Quenching and Intercritical Annealing in a Medium Manganese Steel

et al. 2020

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“…However, it is limited to study the microstructure evolution during deformation under conventional quasi-static deformation. By using quasi-situ electron backscatter diffraction (EBSD) measurements [ 10 , 11 , 12 ] to study the evolution of the retained austenite (RA) fraction with deformation, we can clearly characterize the morphology and volume fraction evolution of RA grains with typical orientation. In the present work, 1180 MPa-grade Q&P steel was used as the investigated material.…”

Section: Introductionmentioning

confidence: 99%

Quasi-Situ Characterization of Retained Austenite Orientation in Quenching and Partitioning Steel via Uniaxial Tensile Tests

et al. 2020

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As a representative of the third generation of advanced high strength steel, the quenching and partitioning steel has excellent potential in automobile manufacturing. The characterization and analysis of the mechanical properties and microstructure of the quenching and partitioning steel during deformation is an effective way to explore the microstructure evolution and transformation-induced plasticity effects of complex phase steels. The relationship between the microstructure morphology and mechanical properties of a 1180 MPa-grade quenching and partitioning steel was investigated through interrupted uniaxial tensile tests plus quasi-situ electron backscatter diffraction measurements. A mixture of ferrite, martensite, and retained austenite was observed in the microstructure. It was found that the volume fraction of global retained austenite decreased linearly with the increase of displacement (0 mm–1.05 mm). The evolution of the retained austenite with typical crystal direction ranges with deformation was characterized. Results show that the orientation (111) and (311) account for the highest proportion of retained austenite grains in the undeformed sample and the mechanical stability of the (311) retained austenite grains is the best. Moreover, the retained austenite grains rotated significantly in the early stage of the specimen deformation process (around yielding), and the work hardening of the specimen was weak at this stage, simultaneously.

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Effect of pre-existed austenite on austenite reversion and mechanical behavior of an Fe-0.2C-8Mn-2Al medium Mn steel

Cited by 165 publications

References 51 publications

Contribution of austenite-martensite transformation to deformability of advanced high strength steels: From atomistic mechanisms to microstructural response

Contribution of austenite-martensite transformation to deformability of advanced high strength steels: From atomistic mechanisms to microstructural response

Control of Core-shell Type Second Phase Formed via Interrupted Quenching and Intercritical Annealing in a Medium Manganese Steel

Quasi-Situ Characterization of Retained Austenite Orientation in Quenching and Partitioning Steel via Uniaxial Tensile Tests

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