Characterization of Nanoscale Mn/Fe-Rich Intermetallic B2-NiAl in Ultra-Low Carbon Bainitic Steel with Super-High Strength

An ultra-low carbon bainitic steel is developed through nanoprecipitation of high-density Mn/Fe-rich intermetallic B2-NiAl. A high yield strength of ~ 1.3 GPa and a good total elongation of ~ 13 pct are attained via minimal lattice misfit nanoprecipitation. Atom probe tomography and high-resolution transmission electron microscope were applied to characterize nanoscale precipitates. An increment of 544 MPa in yield strength is achieved after an aging process, predominantly attributed to the order strengthening mechanism.