Abstract
Novel Fe–28Mn–10Al–C–0.5Nb low-density steel was developed and the room temperature tensile behavior in the solid solution state and the microstructure evolution process during plastic deformation were studied, aiming to clarify the dominant deformation mechanisms. The results show that the developed steel was fully austenitic with a low density of 6.63 g/cm3 and fairly high stacking fault energy of 84 MJ/m2. The present fully austenitic Fe–28Mn–10Al–C–0.5Nb low-density steel exhibited an excellent ultimate tensile strength of 1084 MPa and elongation of 37.5%; in addition, the steel exhibited an excellent combination of strength and ductility (i.e., the product of strength and ductility (PSE) could reach as high as 40.65 GPa%). In spite of the high stacking fault energy, deformed microstructures exhibited planar glide characteristics, seemingly due to the glide plane softening effect. The excellent combination of strength and ductility is attributed to plasticity induced by microbands and leads to the continuous strain hardening during deformation at room temperature. Moreover, the addition of Nb does not change the deformation mechanism and strengthening mechanism of Fe–Mn–Al–C low-density steel, and can optimize the mechanical properties of the steel.
Highlights
College of Metallurgy &Energy, North China University of Science and Technology, Tangshan 063210, China; Citation: Ma, T.; Gao, J.; Li, H.; Li, C.; Abstract: Novel Fe–28Mn–10Al–C–0.5Nb low-density steel was developed and the room temperature tensile behavior in the solid solution state and the microstructure evolution process during plastic deformation were studied, aiming to clarify the dominant deformation mechanisms
Several advanced steel materials with a combination of strength and ductility (i.e., tensile strength (TS) × elongation) of 15,000–20,000 MPa% have been applied to automobile sheet steels such as gapless steel, high strength low alloys (HSLA), transformation induced plasticity steel (TRIP), twin-induced plasticity steel (TWIP), etc. [1,2]
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Summary
College of Metallurgy &Energy, North China University of Science and Technology, Tangshan 063210, China; Citation: Ma, T.; Gao, J.; Li, H.; Li, C.; Abstract: Novel Fe–28Mn–10Al–C–0.5Nb low-density steel was developed and the room temperature tensile behavior in the solid solution state and the microstructure evolution process during plastic deformation were studied, aiming to clarify the dominant deformation mechanisms. The results show that the developed steel was fully austenitic with a low density of 6.63 g/cm and fairly high stacking fault energy of 84 MJ/m2. The weight savings of commercially available automotive sheet steels are not effective due to the low alloying of light elements such as Al. Several recent investigations have revealed that Fe–Mn–Al–C steel, prepared by adding Al to high Mn austenitic steel, can be used in automobile manufacturing to realize automobile lightweight [3,4] due to its low density, excellent mechanical properties, formability, and weldability. Compared with TRIP/TWIP steel, Fe–Mn–Al–C steel has lower density and better mechanical properties with considerable Al addition (e.g., 10%) [8,9,10,11,12] These effects mainly result from the stacking fault energy (SFE) increase with the addition of Al in the high. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
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