Fe–Mn–C–Al Low‐Density Steel for Structural Materials: A Review of Alloying, Heat Treatment, Microstructure, and Mechanical Properties

Aluminum (Al) containing Fe–Mn–C–Al steel exhibits lightweight and outstanding mechanical properties, bringing considerable applications in vehicle, airplane, and mining industries as structural materials and components. The addition of C and Al elements into Fe–Mn iron matrix, following with subsequent heat treatment, plays an important role in microstructure controlling, such as single phase (austenite structure) or duplex phases (mixing with ferritic and austenite) matrix, as well as the short range order and κ‐carbide precipitation. These microstructural evolutions considerably influence the mechanical properties of low‐density steel, especially of the work hardening, tribological, cryogenic, and hydrogen embrittlement performance. The current article introduces the progress of alloying and heat treatment, as well as the subsequent heat treatment effects on microstructural evolution and mechanical properties of Al‐containing low‐density steel. The recent research progress on Al‐containing low‐density steel shall provide a valuable source of ideas for high‐quality, low‐density steel design, and engineering applications.