Microstructural and mechanical evolution of duplex Fe-Mn-Al-C steels during microstructural conditioning: Influence of vanadium microalloying

Low-density (LD) steels of the Fe-Mn-Al-C system hold promise for automotive, aerospace, and military applications due to their strength-ductility balance and reduced density. These steels harden through deformation and kappa-carbide precipitation, significantly impacting ductility. This study aims to investigate the microstructural and mechanical properties of duplex Fe-12Mn-8Al-1C LD steels, non- and microalloyed with 0.2 wt% V. Both steels were vacuum-melted, homogenized, and hot-rolled at 1150 degrees C to 5 mm thickness, followed by a solution treatment at 1200 degrees C. Characterization was performed using LOM, SEM, XRD, and HV tests. Results showed grain refinement and a recrystallized microstructure, particularly in the V-microalloyed steel. In addition, SEM analysis showed VC formation and XRD confirmed austenite as the matrix phase, as well as the presence of ferrite and kappa-carbides in both steels. Microhardness values increase from 389 to 437 HV in V-microalloyed steel, mainly due to strain hardening and VC precipitation.