LAUSR

ABSTRACT The microstructural evolution and deformation behaviour of Fe-(13, 16, 18)Mn-8Al-0.8C (wt-%) low-density steels were investigated in the present work. During aging treatment, the increase in the volume fraction of κ’-carbides significantly improved the yield strength. The formation of κ/α lamellae increased the strain hardening rate. However, large fractions of intergranular κ-carbides deteriorated the ductility of the materials. Mn element stabilised austenite, restricted the precipitation of intergranular κ-carbides and delayed the formation of intragranular κ’-carbides, leading to the uniform distribution of the strain. Increasing Mn content also postponed the peak aging. A good balance of strength and ductility can be achieved by short-time aging treatment in the low-Mn steels or long-time aging treatment in the high-Mn steels.