Nowadays, the automotive industry is focused on developing lightweight steels due to their combination of low density and excellent mechanical properties, such as stiffness and high specific strength. These lightweight materials are attractive to this engineering field because the low-density materials present a transformative effect on the lightweighting of automotive structures [1]. In this work, a fully austenitic Fe-30Mn-9Al-1C steel is studied after different aging treatments. Artificial aging enables formation of kappa-carbides via spinoidal decomposition resulting in increased mechanical strength.

The microstructure of the material is thoroughly analyzed using SEM, EBSD and HRTEM. The effect of kappa-carbides on strength is investigated on macro-scale via tensile testing and on micro-scale via Nanoindentation. The relationship between microstructure and mechanical properties on macro- and microscales is analyzed. It is shown that there is a clear correlation between properties on macro- and microscales.