Fe–Al–Mn–C lightweight structural alloys: a review on the microstructures and mechanical properties

Abstract

Adding a large amount of light elements such as aluminum to steels is not a new concept recalling that several Fe–Al–Mn–C alloys were patented in 1950s for replacement of nickel or chromium in corrosion resistance steels. However, the so-called lightweight steels or low-density steels were revisited recently, which is driven by demands from the industry where steel has served as a major structural material. Strengthening without loss of ductility has been a triumph in steel research, but lowering the density of steel by mixing with light elements will be another prospect that may support the competitiveness against emerging alternatives such as magnesium alloys. In this paper, we review recent studies on lightweight steels, emphasizing the concept of alloy design for microstructures and mechanical properties. The influence of alloying elements on the phase constituents, mechanical properties and the change of density is critically reviewed. Deformation mechanisms of various lightweight steels are discussed as well. This paper provides a reason why the success of lightweight steels is strongly dependent on scientific achievements even though alloy development is closely related to industrial applications. Finally, we summarize some of the main directions for future investigations necessary for vitalizing this field of interest.

Strain hardening in Fe–16Mn–10Al–0.86C–5Ni high specific strength steel

“…yield strength-to-mass density ratio) [4,5,17e27]. These lowdensity steels, mainly based on an FeeAleMneC alloy system containing high contents of Mn (16e28 wt.%), Al (3e12 wt.%) and C (0.7e1.2 wt.%), consist of face-centered cubic (fcc) austenite matrix and body-centered cubic (bcc) ferrite matrix and finely dispersed nanometer-sized k-carbides of (Fe,Mn) 3 AlC type (the so-called TRIPLEX steel) [18,19]. Recently, Kim et al [27] showed a new variation: their Fee16Mne10Ale0.86Ce5Ni high specific strength steel (HSSS) has a hard FeAl-type (B2) intermetallic compound as the strengthening second phase, and the alloying of Ni catalyzes the precipitation of B2 particles in the fcc matrix.…”

Microstructure and mechanical properties of 980MPa grade Fe-Mn-Al-C lightweight steel

“…Concepts of Fe-Al-Mn-C-based lightweight steels are fairly simple, but primary metallurgical issues are complicated [7][8]. This is because the lightweight steels can have ferritic, austenitic, or even multiphase structure, depending on contents of primary alloying elements of C, Mn, or Al, which complicatedly changes deformation mechanisms as well [9][10].…”

Influence of κ-carbide interface structure on the formability of lightweight steels

“…Lightweight steel is desirable in manufacturing of fuel-economy and emission-reduction transportation components [1]. The challenge in fabrication of high Al steel includes clogging in continuous casting and cracking in cold working.…”