Abstract
Lightweight Fe-Mn-Al-C steels have low density, and high mechanical properties, which makes them a possibility for weight reduction in vehicles for road transport. In steel production, as-cast microstructure is an important parameter for further processing. The as-cast microstructure of five lightweight duplex steels was investigated: Fe-15Mn-10Al-0.8C, Fe-15Mn-10Al-1.7Ni-0.8C, Fe-15Mn-10Al-3.9Ni-0.8C, Fe-15Mn-10Al-5.6Ni-0.8C and Fe-15Mn-10Al-8.6Ni-0.8C. The influence of Ni was analysed through thermodynamic calculations and microstructural characterization. The samples were analysed through an optical and electron microscopy. The base microstructure of the studied steel consists of ferrite and austenite. Further investigation showed that the decomposition of austenite was accompanied by the formation of kappa carbides and the B2 ordered phase. The addition of Ni prevented the formation of a lamellar kappa ferrite morphology, but at 5.6 wt.% Ni, the decomposition of austenite was most severe, resulting in a large amount of kappa carbides and a B2 ordered phase.
Highlights
Reducing CO2 emissions by minimising vehicle mass [3,4,5] is an important aspect for sustainable transport
The samples were etched in 10% Nital and for electron backscattered diffraction measurements the polished samples were polished with oxide polishing suspension (OPS) for 5 min
The same trend is observed in the solidus temperature, which decreases from 1299 ◦ C (FeMnAlC) to 1245 ◦ C (FeMnAl8.6NiC)
Summary
Reducing CO2 emissions by minimising vehicle mass [3,4,5] is an important aspect for sustainable transport. The matrix phase of lightweight steels can be ferritic, austenitic, or duplex (ferritic and austenitic) depending on the chemical composition, mainly Al, C, and Mn [6,9,10,11,12]. The high Al content promotes the formation of a B2 ordered phase and nano-sized kappa carbides (κ). The addition of Ni to the Fe-Mn-Al-C steel system can promote the precipitation of the B2 ordered phase in the γ-austenite matrix (FCC) [16,17,18,19,20,21]. The as-cast microstructure of steels is important for applications in castings as well as for further processing of ingots, billets, slabs, etc. The formation of different phases in the microstructure of Academic Editor: José L. Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
