Effect of Nb Alloying and Solution Treatment on the Mechanical Properties of Cold-Rolled Fe-Mn-Al-C Low-Density Steel

The automotive industry’s rapid expansion has made the development of lightweight, high-strength automotive steels essential for both energy efficiency and emission reduction. Among these materials, Fe-Mn-Al-C steel has drawn considerable interest due to its favorable combination of low density and...

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Main Authors: Litu Huo, Jianxin Gao, Yungang Li, Pengfei Xu, Xiangyu Wei, Tao Ma
Format: Article
Language:English
Published: MDPI AG 2025-01-01
Series:Metals
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Online Access:https://www.mdpi.com/2075-4701/15/2/102
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author Litu Huo
Jianxin Gao
Yungang Li
Pengfei Xu
Xiangyu Wei
Tao Ma
author_facet Litu Huo
Jianxin Gao
Yungang Li
Pengfei Xu
Xiangyu Wei
Tao Ma
author_sort Litu Huo
collection DOAJ
description The automotive industry’s rapid expansion has made the development of lightweight, high-strength automotive steels essential for both energy efficiency and emission reduction. Among these materials, Fe-Mn-Al-C steel has drawn considerable interest due to its favorable combination of low density and high strength. This research examines the impact of Nb alloying (with Nb content of 0% and 0.5%) and solution treatment on the microstructure and mechanical properties of cold-rolled Fe-28Mn-10Al-C low-density steel. Various methods were employed, including Thermo-Calc thermodynamic simulations, the Olson–Cohen model, X-ray diffraction (XRD), metallographic microscopy, room-temperature tensile testing, and scanning electron microscopy (SEM). The findings demonstrate that Nb alloying significantly refines the austenite grain structure of the Fe-28Mn-10Al-C steel, improving both strength and ductility in comparison to the 0Nb steel. After solution treatment at 1050 °C for 30 min, the cold-rolling-induced defects are effectively removed, leading to a substantial increase in elongation at fracture (38.14–44.45%) and an ultimate tensile strength exceeding 900 MPa. As the solution treatment temperature increases, the austenite grains coarsen, and the number of twins increases, while yield strength and ultimate tensile strength decrease. However, there is a notable enhancement in ductility, with the material exhibiting a ductile fracture mechanism. These results offer valuable insights and a theoretical foundation for further improving the mechanical properties of Fe-Mn-Al-C low-density steels.
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spelling doaj-art-34b5b0f06a6b4cb290910210db821fc22025-08-20T02:03:25ZengMDPI AGMetals2075-47012025-01-0115210210.3390/met15020102Effect of Nb Alloying and Solution Treatment on the Mechanical Properties of Cold-Rolled Fe-Mn-Al-C Low-Density SteelLitu Huo0Jianxin Gao1Yungang Li2Pengfei Xu3Xiangyu Wei4Tao Ma5College of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, ChinaCollege of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, ChinaCollege of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, ChinaCollege of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, ChinaCollege of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, ChinaCollege of Metallurgy and Energy, North China University of Science and Technology, Tangshan 063210, ChinaThe automotive industry’s rapid expansion has made the development of lightweight, high-strength automotive steels essential for both energy efficiency and emission reduction. Among these materials, Fe-Mn-Al-C steel has drawn considerable interest due to its favorable combination of low density and high strength. This research examines the impact of Nb alloying (with Nb content of 0% and 0.5%) and solution treatment on the microstructure and mechanical properties of cold-rolled Fe-28Mn-10Al-C low-density steel. Various methods were employed, including Thermo-Calc thermodynamic simulations, the Olson–Cohen model, X-ray diffraction (XRD), metallographic microscopy, room-temperature tensile testing, and scanning electron microscopy (SEM). The findings demonstrate that Nb alloying significantly refines the austenite grain structure of the Fe-28Mn-10Al-C steel, improving both strength and ductility in comparison to the 0Nb steel. After solution treatment at 1050 °C for 30 min, the cold-rolling-induced defects are effectively removed, leading to a substantial increase in elongation at fracture (38.14–44.45%) and an ultimate tensile strength exceeding 900 MPa. As the solution treatment temperature increases, the austenite grains coarsen, and the number of twins increases, while yield strength and ultimate tensile strength decrease. However, there is a notable enhancement in ductility, with the material exhibiting a ductile fracture mechanism. These results offer valuable insights and a theoretical foundation for further improving the mechanical properties of Fe-Mn-Al-C low-density steels.https://www.mdpi.com/2075-4701/15/2/102Fe-Mn-Al-CNbmicrostructurethermodynamicsSFEmechanical properties
spellingShingle Litu Huo
Jianxin Gao
Yungang Li
Pengfei Xu
Xiangyu Wei
Tao Ma
Effect of Nb Alloying and Solution Treatment on the Mechanical Properties of Cold-Rolled Fe-Mn-Al-C Low-Density Steel
Metals
Fe-Mn-Al-C
Nb
microstructure
thermodynamics
SFE
mechanical properties
title Effect of Nb Alloying and Solution Treatment on the Mechanical Properties of Cold-Rolled Fe-Mn-Al-C Low-Density Steel
title_full Effect of Nb Alloying and Solution Treatment on the Mechanical Properties of Cold-Rolled Fe-Mn-Al-C Low-Density Steel
title_fullStr Effect of Nb Alloying and Solution Treatment on the Mechanical Properties of Cold-Rolled Fe-Mn-Al-C Low-Density Steel
title_full_unstemmed Effect of Nb Alloying and Solution Treatment on the Mechanical Properties of Cold-Rolled Fe-Mn-Al-C Low-Density Steel
title_short Effect of Nb Alloying and Solution Treatment on the Mechanical Properties of Cold-Rolled Fe-Mn-Al-C Low-Density Steel
title_sort effect of nb alloying and solution treatment on the mechanical properties of cold rolled fe mn al c low density steel
topic Fe-Mn-Al-C
Nb
microstructure
thermodynamics
SFE
mechanical properties
url https://www.mdpi.com/2075-4701/15/2/102
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