Kappa Carbide Precipitation in Duplex Fe-Al-Mn-Ni-C Low-Density Steel

The microstructural evolution of a Fe-Mn-Al-Ni-C low-density steel was studied. lightweight steels are promising material for the transportation industry, due to their good mechanical properties and low density. base microstructure investigated consists ferrite austenite. Thermo-Calc calculations showed formation an ordered BCC (body-centred cubic) B2 phase below 1181 °C kappa carbides 864 °C. produced in vacuum induction furnace, cast into ingots hot forged bars. bars were solution annealed then isothermally at 350, 450, 550, 650, 750, 850 as-cast state, annealed, by optical microscopy scanning electron microscopy. results phase. appeared sample grain boundaries samples. At 550 °C, began form austenite coarsened with increasing temperature.