Microstructure and mechanical properties of an Fe–Mn–Al–C lightweight steel after dynamic plastic deformation processing and subsequent aging

Cen

et al. 2023

steel research int.

The flow stress curves of Fe‐31.7Mn‐11.5Al‐0.9C low‐density steel are obtained by a hot‐compression test with a Gleeble‐3500 thermomechanical simulator. It is shown in the results that the dynamic recovery and dynamic recrystallization (DRX) of δ‐ferrite occur preferentially under the same deformation condition, inducing a “yield point‐like” phenomenon in the true stress–strain curves. The Zener–Hollomon parameter is introduced to fit the characteristic parameters used to establish the flow stress model according to Arrhenius hyperbolic sine relationship and Avrami equation, and the DRX activation energy of austenite is 414.12 KJ mol−1. The hot‐processing maps at different true strains are simulated based on the dynamic material model to determine the suitable hot‐rolling process and the optimal hot‐working process selection of high strain rate and high deformation temperature combination, 1100–950 °C/1–0.2 s−1, is recommended.

Section: Drv Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Thermomechanical Treatment Performance and Flow Stress Model of a Fe–Mn–Al–C Low‐Density Steel

Cen

et al. 2023

steel research int.

“…It has been reported that the formation of L'1 2 type 'Fe(Mn)3AlC phase (κ) can be promoted by holding Fe-Mn-Al-C steel with high Mn and Al content at 450-550 • C for several hours. [17][18][19][20][21][22][23] and the tensile strength can be improved by a precipitation hardening mechanism. [17,18,24,25].…”

Section: Introductionmentioning

confidence: 99%

Effect of κ Carbides on Deformation Behavior of Fe-27Mn-10Al-1C Low Density Steel

Liu

et al. 2022

Crystals

Fe-Mn-Al-C steel, which is a potential lightweight material for automobiles, has a variety of microstructures and good mechanical properties. The effect of κ carbides on the mechanical properties and strain hardening rate of Fe-27Mn-10Al-1C (wt.%) low density steel was studied by short-time heat treatment to control the precipitation behavior of κ carbides. Quenched specimens have an excellent combination of strength and plasticity and continuous high strain hardening rate, which is due to the uniform distribution of κ carbides with an average size of 1.6 nm in an austenite matrix. The fracture mode of the sample changed from ductile fracture to cleavage fracture, which was because the aging treatment promoted the precipitation of B2 phases and κ carbides at grain boundaries. The size and volume fraction of nanoscale κ carbides in austenite grains increase with the increase of aging temperature, and the yield strength increases but the density of slip bands decreases, resulting in the gradual decrease of strain hardening rate.

“…The TRIPLEX steels showed an excellent balance of high strength (700-1100 MPa) and tensile ductility (elongation up to 60%) caused by the shear band induced plasticity behavior during tensile deformation and precipitation strengthening by κ-carbides. Li et al [7] reported an austenitic Fe-26Mn-8Al-0.8C-0.1Nb-0.3Mo (wt%) lightweight steel processed by dynamic plastic deformation (DPD) with strain up to 0.75 followed by aging at 450 °C. The DPD process led to an increase in the yield strength of approximately %190% compared to the as-received sample due Fe-30Mn-10.5Al-1.1C alloys with different Mo and Ni contents are prepared to investigate the phase transformation behavior and mechanical properties of austenitic lightweight steels.…”

Section: Introductionmentioning

confidence: 99%

Synergetic Effects of Complex Additions of Mo and Ni on the Phase Transformation Behavior and Mechanical Properties of Austenitic Lightweight Steels

Moon

Park

Kim

et al. 2022

steel research int.

Fe–30Mn–10.5Al–1.1C alloys with different Mo and Ni contents are prepared to investigate the phase transformation behavior and mechanical properties of austenitic lightweight steels. Solution‐treated samples have microstructures consisting of an austenite matrix and ordered κ‐carbides, and the size of the κ‐carbides decreases with the addition of Mo or Ni. In addition, the ordered body‐centered cubic (BCC) phases of B2 and DO3 also form when 3wt%Mo and 3wt%Ni are complexly added, resulting in a large decrease of the austenite grain size. Nanoindentation experiments show that the intrinsic strength of the austenite matrix changes depending on the precipitation behavior of the κ‐carbide; i.e., the addition of 3wt%Mo or 3wt%Ni decreases the intrinsic strength of the austenite by suppressing κ‐carbide precipitation, while complex additions of 3wt%Mo and 3wt%Ni increase them again. The results of tensile tests show that the alloy containing both 3wt%Mo and 3wt%Ni exhibits the highest yield (1102 MPa) and tensile strength (1155 MPa) with large tensile ductility (33%) due to the effects of grain refinement of the austenite grains and formation of secondary hard phases of DO3 and B2, as well as κ‐carbides. Finally, the changes in the precipitation behavior of the κ‐carbide are investigated via transmission electron microscopy and atom probe tomography analyses.