Critical assessment: Processing, microstructure and mechanical properties of Al-containing ferrite-based low-density steels

Over the past three decades, research on aluminium (Al)-containing low-density steels (LDS) has accelerated due to their ∼8–15% lower density than conventional steels, increasing their demand in lightweight automotive applications, high-temperature applications and cryogenic uses such as storage tanks and spacecraft. This review focuses on Al-containing ferritic low-density steels (FLDS). It begins with a discussion of the formation of the κ-carbide and B2/DO 3 phases, the melting and casting route, followed by an overview of microstructural evolution. Furthermore, the elastic modulus, effects of microalloying elements on mechanical properties, deformation mechanisms and the influences of microstructure and strain-hardening behaviour on tensile properties are critically reviewed. Finally, future research directions for optimising the microstructure–mechanical property relationships in FLDS are discussed.