Nanoprecipitate-hardened 1.5 GPa steels with unexpected high ductility

We present mechanical and microstructure results on precipitation-hardened ductile high-strength martensitic and austenitic–martensitic steels (up to 1.5 GPa strength) with good ductility. The alloys have a low-carbon content (0.01 wt.% C), 9–12 wt.% Mn, and minor additions of Ni, Ti and Mo (1–2 wt.%). Hardening is based on transformation-induced plasticity and the formation of intermetallic nanoprecipitates in the martensite during heat treatment (aging). The approach leads to an unexpected simultaneous increase in both strength and total elongation.